JP6910263B2 - Sealed structure - Google Patents

Description

The present invention relates to a sealing structure for sealing a gap between a housing and a shaft rotatably arranged relative to the housing.

Patent Document 1 discloses a sealing device for sealing a gap between a housing and a shaft arranged so as to be relatively rotatable about the housing. This type of sealing device is used in various hydraulic equipment, hydraulic equipment, and pneumatic equipment to seal a fluid. These devices include, for example, engines, motors, generators, pumps, compressors, power steering of automobiles.

Japanese Patent No. 4051865

This type of sealing device may be used to seal fluids of extremely high pressure. Also, this type of sealing device may be used in equipment where the speed of rotation of the shaft with respect to the housing is very high.

Therefore, the present invention provides a sealing structure having high durability even when a high pressure is applied to the fluid to be sealed in a usage environment in which the rotation speed of the shaft with respect to the housing is very high.

The sealing structure according to an aspect of the present invention is arranged in a fluid space in which a fluid is arranged, a housing having a shaft hole leading to the fluid space, and the fluid space and the shaft hole of the housing. A shaft having a cylindrical portion that rotates relative to the housing and a peripheral groove formed in the shaft or the housing are fitted to close the gap between the shaft and the housing. A resin seal ring that suppresses leakage of the fluid from the fluid space of the housing, a mounting portion that is attached to the shaft hole without a gap, and a shaft that is arranged radially inside the mounting portion and slides. It has a sliding sealing portion that movably contacts and an elastic portion made of an elastomer that presses the sliding sealing portion inward in the radial direction toward the shaft, and is closer to the atmosphere than the seal ring. An annular sealing device that is arranged and closes the gap between the shaft and the housing and is formed in the housing and leads to the shaft hole at a position between the sealing ring and the sealing device. It is provided with a drain hole for discharging the fluid that has passed through the seal ring from the fluid space.

In this embodiment, the resin seal ring arranged on the fluid space side of the housing closes the gap between the shaft and the housing to suppress the leakage of the fluid from the fluid space. Since the sealing ring that receives the pressure of the fluid is interposed between the fluid space and the sealing device, the sealing device arranged on the atmosphere side of the sealing ring is not directly exposed to the high pressure of the fluid to be sealed. That is, under the pressure relaxed by the seal ring, the sealer closes the gap between the shaft and the housing. Therefore, in a usage environment where the rotation speed of the shaft with respect to the housing is very high, even if a high pressure is applied to the fluid to be sealed, the sealing device and thus the sealing structure have high durability and can be used for a long period of time. can. The drain hole is formed at a position between the seal ring and the sealing device, and discharges the sealed fluid that has passed through the sealing ring from the fluid space from the shaft hole, and does not give an excessive load to the sealing device. This also enhances the durability of the sealing device and thus the sealing structure.

Preferably, the seal ring is formed from an elongated curved rod having two ends, the two ends being slidably contacted with each other in the circumferential direction of the seal ring to provide the seal. Each of the contact portions allows expansion of the ring in the circumferential direction, and even if the contact portions slide with each other, the seal ring is continuous in the circumferential direction as long as the contact portions are in contact with each other.

In this case, since the seal ring is formed from a long curved rod having two ends, the seal ring is fitted on the shaft or in the circumferential groove formed in the housing. Easy to place around. Further, even if the contact portions of the two ends slide with each other, as long as the contact portions are in contact with each other, the seal ring maintains a continuous endless ring shape in the circumferential direction, so that the seal ring is in the circumferential direction. Even if it is expanded to, the sealing performance of the seal ring is not impaired.

Preferably, the sliding sealing portion of the sealing device is formed with a spiral groove that returns 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 sealed fluid passes through the sealing device, the sealed fluid is returned from the atmospheric side to the fluid space side by the spiral groove, so that the sealing performance of the sealed structure is improved.

It is sectional drawing which shows the sealed structure which concerns on 1st Embodiment of this invention. It is a front view which shows the seal ring of the sealing structure of FIG. It is a perspective view which shows both ends of the rod which constitutes the seal ring of FIG. It is a front view which shows the seal ring which concerns on the modification. It is a perspective view which shows both ends of the rod which constitutes the seal ring of FIG. It is a developed view of the seal lip of the sealing device of the sealing structure of FIG. It is sectional drawing which shows the sealed structure which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the sealed structure which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the sealed structure which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the sealed structure which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the sealed structure which concerns on 6th Embodiment of this invention. It is sectional drawing which shows the sealed 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 accompanying drawings. The sealing structure according to the present invention is used for sealing a fluid in various hydraulic equipment, hydraulic equipment, and pneumatic equipment. These devices include, for example, engines, motors, generators, pumps, compressors, power steering of automobiles.

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

The sealing structure 1 includes a housing 4, a shaft 2, a sealing 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 arranged, and a shaft hole 4A that leads to the fluid space A. The shaft hole 4A has 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 with the small diameter portion 4B and on the atmospheric space B side.

The shaft 2 is arranged in the fluid space A and the shaft hole 4A of the housing 4, 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 housing 4 may rotate around the central shaft Ax with the shaft 2 fixed. In this embodiment, the shaft 2 is a cylinder, but at least the portion arranged in the shaft hole 4A may be a cylinder.

A peripheral groove 2A is formed on the outer peripheral surface of the shaft 2. The peripheral groove 2A is formed at a position overlapping the small diameter portion 4B of the shaft hole 4A. A resin seal ring 6 is fitted in the peripheral 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, and traps the fluid to be sealed in the fluid space A of the housing 4. The outer portion of the seal ring 6 projects radially outward from the peripheral 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 arranged closer to the atmosphere than the sealing 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 has an annular shape with the central axis Ax as the axis of symmetry, but in FIG. 1, only the upper portion of the sealing device 10 is shown.

The sealing device 10 has a double structure and has an elastic body, that is, an elastic ring 12 formed of an elastomer, and a rigid body that adheres to the elastic ring 12 and reinforces the elastic ring 12, for example, a metal reinforcing ring 14. .. 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 has an outer annular body 15, an inner annular body 16, and a flange 17. The outer annular body 15 is a mounting portion that is mounted without a gap in the large diameter portion 4C of the shaft hole 4A. The mounting method is not limited, but may be, for example, a tight fit. The outer annular body 15 has a portion of an elastic ring 12 and a portion of a reinforcing ring 14. The portion of the reinforcing ring 14 of the outer annular body 15 applies a force outward in the radial direction to the portion of the elastic ring 12, and firmly presses the portion of the elastic ring 12 of the outer annular body 15 against the large diameter portion 4C of the shaft hole 4A. do.

The inner annular body 16 is arranged coaxially with the outer annular body 15 on the radial inner side of 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 from an elastic body.

The inner annular body 16 has a seal lip (sliding sealing portion) 18. The seal lip 18 is arranged inside the outer annular body 15 in the radial direction, and the outer peripheral surface of the shaft 2 is slidably contacted with the seal lip 18. The seal lip 18 suppresses leakage of the sealed fluid from the fluid space A side to the atmospheric 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 atmospheric space B side). FIG. 1 shows a state in which the tip edge between the inclined surface 18A and the inclined surface 18B is in contact with the outer peripheral surface of the shaft 2 and is deformed.

The elastic ring 12 presses the seal lip 18, which is a sliding sealing portion formed on the elastic ring 12, inward in the radial direction toward the shaft 2. A garter spring 20 that compresses the inner annular body 16 inward in the radial direction is wound around the inner annular body 16. The garter spring 20 applies a force that presses the seal lip 18 against the outer peripheral surface of the shaft 2 to the seal lip 18.

A drain hole 8 is formed in the housing 4. The drain hole 8 leads to 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 discharges the fluid that has entered the large diameter portion 4C from the fluid space A through the seal ring 6. The fluid is discharged through the drain hole 8 by the pressure in the large diameter portion 4C. The number of drain holes 8 may be one or a plurality. The shape and dimensions of the drain hole 8 are not limited.

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

Since the seal ring 6 is composed of a long curved rod having two ends 6A, the seal ring 6 is fitted into the peripheral groove 2A formed on the outer peripheral surface of the shaft 2. It is easy to arrange around the shaft 2.

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

4 and 5 show a modified seal ring 7 that can be used in the embodiment. The seal ring 7 is formed of the same material as the seal ring 6 and is fitted into the peripheral groove 2A in the same manner as the seal ring 6. The two ends 7A and 7B of the seal ring 7 each have two contact portions that allow the seal ring 7 to expand in the circumferential direction (and thus in the radial direction).

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

When the two ends 7A and 7B are butted against each other, the radial inner surface (lower surface in FIG. 5) of the protruding contact portion 7E of the end portion 7A becomes the radial outer surface of the sliding guide portion 7H of the end portion 7B (the lower surface in FIG. 5). In FIG. 5, the upper surface is slidably contacted, and the radial outer surface (upper surface in FIG. 5) of the sliding guide portion 7F of the end portion 7A is the radial inner surface of the protruding contact portion 7G of the end portion 7B. It makes slidable contact with (lower surface in FIG. 5). In this way, the sliding guide portion 7H guides the sliding of the protruding contact portion 7E, and the sliding guide portion 7F guides the sliding of the protruding contact portion 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 above the sliding guide portion 7H. The side surface 7G1 of the protruding contact portion 7G of the end portion 7B contacts the side surface 7E1 of the protruding contact portion 7E of the end portion 7A and / or the side surface 7F1 above the sliding guide portion 7F.

Since the seal ring 7 is composed of a long curved rod having two end portions 7A, the seal ring 7 is fitted into the peripheral groove 2A formed on the outer peripheral surface of the shaft 2. It is easy to arrange around the shaft 2.

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

If the seal ring expands in the circumferential direction (and thus in the radial direction) and the endless ring shape that is continuous in the circumferential direction of the seal ring is maintained, use a seal ring that has an end of another structure. You may.

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

FIG. 6 is a developed view of the seal 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 on the atmospheric space B side of the seal lip 18. The grooves 19A and 19B are recessed relative to the inclined surface 18B. That is, the grooves 19A and 19B may be carved into the inclined surface 18B, or ribs may be formed on the inclined surface 18B and the portions recessed relative to the ribs may be used as the grooves 19A and 19B.

The grooves 19A and 19B play a role of returning the fluid from the atmospheric 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 atmospheric space B side to the fluid space A side. The groove 19A conforms to the normal rotation direction, and returns the fluid from the atmospheric space B side to the fluid space A side during the relative normal rotation of the shaft 2 and the housing 4. On the other hand, the groove 19B conforms to the reverse rotation direction opposite to the normal rotation direction, and returns the fluid from the atmospheric space B side to the fluid space A side when the shaft 2 and the housing 4 rotate in the reverse direction.

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

In this embodiment, the grooves 19A and 19B that match both rotation directions are formed in the sealing device 10, but only the grooves that match one rotation direction may be formed in the sealing device 10. Further, the grooves 19A and 19B may be omitted.

In this embodiment, the resin seal ring 6 arranged on the fluid space A side of the housing 4 closes the gap between the shaft 2 and the housing 4 to prevent the sealed fluid from leaking from the fluid space A. Suppress. Since the sealing ring 6 that receives the pressure of the sealed fluid is interposed between the fluid space A and the sealing device 10, the sealing device 10 arranged on the atmosphere side of the sealing ring 6 remains at the high pressure of the sealed fluid. Not exposed. That is, under the pressure relaxed 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 usage environment where the rotation speed of the shaft 2 with respect to the housing 4 is very high, the sealing structure 1 has high durability and can be used for a long period of time even when a high pressure is applied to the fluid to be sealed. .. This effect is also achieved in other embodiments described below.

Further, in this embodiment, since the seal ring 6 for suppressing 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 so, the sealing device 10 arranged closer to the atmosphere than the sealing ring 6 is not directly exposed to the high temperature of the fluid to be sealed. That is, under the temperature relaxed 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 usage environment where the rotation speed of the shaft 2 with respect to the housing 4 is very high, the sealing structure 1 has high durability and can be used for a long period of time even if the fluid to be sealed has a high temperature. can. This effect is also achieved 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 a lower cost than the sealing device according to the second to fourth embodiments described later. However, since the sealing device 10 arranged on the atmosphere side of the sealing ring 6 is not directly exposed to the high pressure of the fluid to be sealed, even the sealing device 10 having a simple structure and can be manufactured at low cost is a sealing ring. It has higher durability and can be used for a long period of time as compared with the case without 6.

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 sealed fluid passing through the seal ring 6 from the fluid space A is passed through the seal ring 6 to have a large diameter of the shaft hole 4A. It is discharged from the part 4C and does not give an excessive load to the sealing device 10. This also enhances the durability of the sealing device 10, and thus the sealing structure 1. This effect is also achieved in other embodiments described below.

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

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

Other features are the same as in the first embodiment. Further, the above-mentioned deformation of the seal ring 6 and the deformation of the spiral groove with respect to the first embodiment can be applied to this embodiment as well.

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

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

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

The sealing device 30 has an outer annular body 15, an inner annular body 16, and a flange 17. The outer annular body 15 is a mounting portion that is mounted without a gap in the large diameter portion 4C of the shaft hole 4A. The mounting method is not limited, but may be, for example, a tight fit. The outer annular body 15 has a portion of an elastic ring 12 and a portion of a reinforcing ring 34. The portion of the reinforcing ring 34 of the outer annular body 15 applies a force outward in the radial direction to the portion of the elastic ring 12, and firmly presses the portion of the elastic ring 12 of the outer annular body 15 against the large diameter portion 4C of the shaft hole 4A. do.

The inner annular body 16 is arranged coaxially with the outer annular body 15 on the radial inner side of 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 annular body 16 has a portion of the elastic ring 12, a portion of the reinforcing ring 32, and a portion of the end portion 36 of the reinforcing ring 34. The portion of the elastic ring 12 of the inner annular body 16 has a seal lip (sliding sealing portion) 18 and a dust strip 22.

Other features are the same as in the first embodiment. Further, the above-mentioned deformation of the seal ring 6 and the deformation of the spiral groove with respect to the first embodiment can be applied to this embodiment as well.

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

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

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

The sealing device 40 has an outer annular body 15, an inner annular body 16, and a flange 17. The outer annular body 15 is a mounting portion that is mounted without a gap in the large diameter portion 4C of the shaft hole 4A. The mounting method is not limited, but may be, for example, a tight fit. The outer annular body 15 has a portion of an elastic ring 12 and a portion of a reinforcing ring 14. The portion of the reinforcing ring 14 of the outer annular body 15 applies a force outward in the radial direction to the portion of the elastic ring 12, and firmly presses the portion of the elastic ring 12 of the outer annular body 15 against the large diameter portion 4C of the shaft hole 4A. do.

The inner annular body 16 is arranged coaxially with the outer annular body 15 on the radial inner side of 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 radial inner end portion of the reinforcing ring 14. The portion of the elastic ring 12 of the inner ring 16 has a dust strip 22. A part of the sliding sealing member 42 is embedded in the elastic ring 12 of the inner annular body 16.

The sliding sealing member 42 is made of a hard resin material having high heat resistance and a low coefficient of friction, such as PEEK, PPS, and PTFE. The outer peripheral surface of the shaft 2 is slidably contacted with 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, inward in the radial direction toward the shaft 2.

Preferably, a spiral groove similar to the grooves 19A and 19B (see FIG. 6) of the first embodiment is formed on the inner peripheral surface of the sliding sealing member 42. A groove suitable for both rotation directions may be formed in the sliding sealing member 42, or only a groove suitable for one rotation direction may be formed in the sliding sealing 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, by extension, the sealing structure 1 may be further enhanced.

Other features are the same as in the first embodiment. Further, the above-mentioned modification of the seal ring 6 with respect to the first embodiment can be applied to this embodiment as well.

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

Fifth Embodiment FIG. 10 shows a sealed structure 1 according to a fifth embodiment of the present invention. In this embodiment, the sealing structure 1 includes an elastic ring 9 that is fitted into the peripheral 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, for example, an elastomer, which has higher elasticity than the material of the seal ring 6. As the elastic ring 9, an O-ring or a ring having a circular cross-sectional shape when uncompressed 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 section, a D ring having a D-shaped cross section, and a ring having a triangular cross section can be used.

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

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

Other features are the same as in the first embodiment. Further, the above-mentioned deformation of the seal ring 6 and the deformation of the spiral groove with respect to the first embodiment can be applied to this embodiment as well. Further, the elastic ring 9 may be used in the sealing structure having the sealing device according to any one of the second to fourth embodiments or another sealing device.

Sixth Embodiment FIG. 11 shows a sealed structure 1 according to a sixth embodiment of the present invention. In this embodiment, unlike the configuration of the first embodiment, a peripheral 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 the resin seal ring 56 is fitted into the peripheral groove 4D. It has been. The peripheral 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 4B of the shaft hole 4A, and traps the fluid to be sealed in the fluid space A of the housing 4. The inner portion of the seal ring 6 projects radially inward from the peripheral groove 4D, 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 and 7 described above with respect to the first embodiment, and may be of the same type as the seal ring 6. A seal ring 56 similar to the seal ring 7 may be used, but in this case, contrary to FIGS. 4 and 5, the protruding contact portions 7E and 7G are arranged on the inside and the sliding guide portion is arranged on the outside. It is preferable that 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 is directed to the outer peripheral surface of the shaft 2. Keep in touch.

Other features are the same as in the first embodiment. Further, the above-mentioned deformation of the spiral groove with respect to the first embodiment can be applied to this embodiment as well. Furthermore, the peripheral groove 4D and the seal ring 56 may be used in the sealing structure having the sealing device or other sealing device according to any one of the second to fourth embodiments.

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

The elastic ring 59 is an endless ring formed of an elastic body, for example, an elastomer, which has higher elasticity than the material of the seal ring 56. As the elastic ring 59, an O-ring or a ring having a circular cross-sectional shape when uncompressed 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 section, a D ring having a D-shaped cross section, and a ring having a triangular cross section can be used.

The elastic body ring 59 is arranged outside the seal ring 56, and is sandwiched between the bottom surface of the peripheral groove 4D of the shaft hole 4A and the outer peripheral surface of the elastic body seal ring 56. The inner portion of the seal ring 56 projects radially outward from the peripheral groove 4D, and the inner peripheral surface of the seal ring 56 contacts the outer peripheral surface of the shaft 2. The elastic ring 59 arranged on the outside of the seal ring 56 presses the seal ring 56 inward in the radial direction. Further, leakage of the sealed fluid between the outer peripheral surface of the seal ring 56 and the bottom surface of the peripheral groove 4D is prevented or reduced by the elastic ring 59. Therefore, according to this embodiment, leakage of the sealed fluid between the inner peripheral surface of the seal ring 56 and the outer peripheral surface of the shaft 2 is further reduced.

The elastic ring 59 is constrained by a hard seal ring 56 inside the peripheral groove 4D. Therefore, even if the high pressure of the fluid space A is applied, there is little possibility that the elastic ring 59 moves from the inside to the outside of the peripheral groove 4D.

Other features are the same as in the sixth embodiment. Further, 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 can be applied to this embodiment as well. Furthermore, the peripheral groove 4D, the seal ring 56, and the elastic body ring 59 may be used in the sealing structure having the sealing device or other sealing device according to any one of the second to fourth embodiments.

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 Shaft hole 4D Circumferential groove 6, 7, 56 Seal ring 6A, 6B, 7A, 7B End 6C, 6D Contact 7E, 7G Protruding contact 8 Drain hole 10 Sealing device 12 Elastic ring (elastic part)
14 Reinforcing ring 15 Outer ring body (mounting part)
16 Inner ring 17 Flange 18 Seal lip (sliding seal)
19A, 19B Spiral groove 30 Sealing device 32,34 Reinforcing ring 40 Sealing device 42 Sliding sealing member (sliding sealing part)

Claims (3)

A housing having a fluid space in which a fluid is arranged and a shaft hole leading to the fluid space,
A shaft that is located in the fluid space and the shaft hole of the housing and has a cylindrical portion that rotates relative to the housing.
Made of resin, which is fitted in a peripheral groove formed in the shaft or the housing, closes a gap between the shaft and the housing, and suppresses leakage of the fluid from the fluid space of the housing. With a seal ring
A mounting portion mounted in the shaft hole without a gap, a sliding sealing portion arranged inside the mounting portion in the radial direction and in contact with the shaft so as to be slidable, and the sliding sealing portion on the shaft. An annular sealing device having an elastic portion made of an elastomer that presses inward in the radial direction, is arranged on the atmosphere side of the sealing ring, and closes a gap between the shaft and the housing. ,
It is provided with a drain hole formed in the housing, which leads to the shaft hole at a position between the seal ring and the sealing device, and discharges the fluid which has passed through the seal ring from the fluid space .
The shaft hole of the housing has a small diameter portion having a circular cross section on the fluid space side and a large diameter portion having a circular cross section coaxial with the small diameter portion and having a circular cross section on the atmospheric side, and is located at a position corresponding to the small diameter portion. A sealing structure characterized in that the seal ring is fitted into the peripheral groove of the shaft or the peripheral groove of the housing surrounding the small diameter portion. The seal ring is formed from a single long curved rod with two ends.
The two ends each have contact portions that are slidably contacted with each other in the circumferential direction of the seal ring to allow expansion of the seal ring in the circumferential direction, and the contact portions slide with each other. However, the sealing structure according to claim 1, wherein the sealing rings are continuous in the circumferential direction as long as the contact portions are in contact with each other. The claim is characterized in that the sliding sealing 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. Item 2. The sealed structure according to Item 1 or 2.

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