JP2013119884A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of reducing wear of a seal ring.SOLUTION: The sealing device 100 fixed in an annular groove 210 formed on a shaft 200 to seal an annular gap between the shaft 200 and a housing 300, includes: a seal ring 10 formed of a rubbery elastic body to be fixed in the annular groove 210; a resin backup ring 20 disposed to closely contact to the side face on the low-pressure side of the annular groove 210; and a rubber ring 30 disposed between the seal ring 10 and the backup ring 20, set so that its inner peripheral side has a fastening margin to the shaft 200 and its outer peripheral side has a fastening margin to the housing 300, and having a hardness higher than that of the seal ring 10 and lower than that of the backup ring 20.

Description

  The present invention relates to a sealing device including a backup ring.

  2. Description of the Related Art Conventionally, as a high-pressure sealing device that seals an annular gap, a sealing device made of a rubber-like elastic body such as an O-ring and a resin backup ring is known. A sealing device according to such a conventional example will be described with reference to FIGS. 7A and 7B are schematic cross-sectional views showing a use state of a sealing device according to a conventional example. FIG. 7A shows a state when no load is applied, and FIG. 7B shows a state when the pressure is high. FIG. 8 is a schematic cross-sectional view showing a state of deterioration over time in a sealing device according to a conventional example.

  The sealing device 500 is mounted in an annular groove 210 provided in the shaft 200 and is provided to seal an annular gap between the shaft 200 and the housing 300 (shaft hole thereof). The sealing device 500 includes a rubber-like elastic seal ring (O-ring) 510 and a resin-made backup ring 520 for preventing the seal ring 510 from protruding into a minute gap outside the annular groove 210. Is done.

  In the sealing device 500 configured as described above, the seal ring 510 is compressed by being pushed to the low pressure side (L) when the pressure is high (see FIG. 7B), and by its own elastic restoring force when there is no load. It will be in the state extended in the direction of an axis (refer to the figure (a)). As a result, when the pressure is high, the seal ring 510 is in close contact with the entire surface of the backup ring 520 on the high pressure side (H), and when the pressure is low, the seal ring 510 is hardly in contact with the backup ring 520. .

  Here, for example, in a fuel piping system in a direct injection engine, when the sealing device 500 is attached at a location where an injector, a high pressure pump or a sensor is attached, the pressure on the high pressure side (H) pulsates. This causes a phenomenon in which the outer peripheral portion 511 and the inner peripheral portion 512 of the low pressure side (L) in the sealing device 500 are worn (see FIG. 8). It is considered that this is because the state of the seal ring 510 is different between no load and high pressure as described above, and the seal ring 510 is repeatedly deformed by pulsation. That is, due to the repeated deformation, friction is generated on the outer peripheral side and the inner peripheral side on the low pressure side of the seal ring 510 by continuously repeating the state in which the seal ring 510 is in contact with and separated from the backup ring 520. It is thought that such a situation has occurred. The backup ring 520 is harder than the rubber seal ring 510 and has a larger surface roughness, so it is considered that the seal ring 510 is likely to be worn.

  As described above, by providing the backup ring 520 on the low pressure side (L) of the seal ring 510, it is possible to suppress the protrusion of the seal ring 510, but the seal ring 510 is worn out in an environment where pulsation occurs. It has occurred. As a result, the sealing performance is adversely affected.

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

  An object of the present invention is to provide a sealing device that can reduce wear of a seal ring.

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

That is, the sealing device of the present invention is
In a sealing device that is mounted in an annular groove provided in one of the two members and seals the annular gap between the two members,
A rubber-like elastic seal ring mounted in the annular groove;
A resin-made backup ring provided in close contact with the low-pressure side surface of the annular groove;
Provided between the seal ring and the backup ring, both the inner peripheral side and the outer peripheral side are set to have a tightening margin with respect to the two members, and the hardness is larger than the seal ring, And a rubber ring with low hardness,
It is characterized by providing.

  According to the present invention, the rubber ring is set so that both the inner peripheral side and the outer peripheral side have a tightening margin with respect to the two members, so that the seal ring can be prevented from protruding at a high pressure. Moreover, since the backup ring is provided on the low pressure side of the rubber ring, the rubber ring can be prevented from protruding. Even if the seal ring is repeatedly deformed due to pressure fluctuation on the high pressure side and friction occurs between the seal ring and the rubber ring, the seal ring is Therefore, wear of the seal ring can be suppressed as compared with the case where friction occurs. Further, since the rubber ring has a higher hardness than the seal ring, it is possible to suppress wear of the rubber ring itself.

  The surface of the rubber ring to which the seal ring is in close contact may be formed in a shape that conforms to the shape of the close contact surface of the seal ring.

  Thereby, since the deformation | transformation of the site | part of the contact | adherence surface with respect to the rubber ring in a seal ring can be suppressed, abrasion of a seal ring can be suppressed further.

  As described above, even when the sealing device is disposed in an environment where the pressure pulsates on the high pressure side, wear of the seal ring can be reduced.

  As described above, according to the present invention, wear of the seal ring can be reduced.

1 is a partially broken cross-sectional view of a sealing device according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view showing a use state (state when no load is applied) of the sealing device according to Embodiment 1 of the present invention. FIG. 3 is a schematic cross-sectional view showing a use state (state at high pressure) of the sealing device according to the first embodiment of the present invention. FIG. 4 is a partially cutaway sectional view of a sealing device according to Embodiment 2 of the present invention. FIG. 5 is a schematic cross-sectional view showing a use state (state without load) of the sealing device according to Embodiment 2 of the present invention. FIG. 6 is a schematic cross-sectional view showing a usage state (a state at high pressure) of the sealing device according to the second embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing a use state of a sealing device according to a conventional example. FIG. 8 is a schematic cross-sectional view showing a state at the time of deterioration in a sealing device according to a conventional example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

Example 1
With reference to FIGS. 1-3, the sealing apparatus 100 which concerns on Example 1 of this invention is demonstrated. Note that the sealing device 100 according to the present embodiment exerts its effect particularly at a location where an injector, a high-pressure pump or a sensor is attached, for example, in a fuel piping system in a direct injection engine. That is, the sealing device 100 according to the present embodiment exhibits its effect particularly when the pressure on the high pressure side (H) pulsates. However, the sealing device 100 according to the present embodiment can be applied to various parts that seal the annular gap between the two members. Hereinafter, the case where it uses as a sealing device for the piping parts of an injector is explained as an example.

<Sealing device>
In particular, the configuration of the sealing device 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. The sealing device 100 includes a rubber-like elastic seal ring 10, a resin backup ring 20, and a rubber ring 30 provided between the seal ring 10 and the backup ring 20. By the sealing device 100 configured in this manner, an annular shape between a shaft (here, an injector) 200 and a housing (here, a pipe) 300 (a shaft hole (here, a pipe inner peripheral surface)) as two members. Seal the gap. The sealing device 100 is attached to an annular groove 210 provided on the outer periphery of the shaft 200, and seals a gap between the outer peripheral surface (groove bottom surface) of the annular groove 210 and the inner peripheral surface of the housing 300.

  The seal ring 10 according to the present embodiment is a so-called O-ring and is made of a rubber material having a Shore A hardness of 70 degrees or more and 80 degrees or less. The seal ring 10 is configured such that the inner peripheral side has a fastening allowance with respect to the shaft 200 and the outer peripheral side has a fastening allowance with respect to the housing 300. That is, the seal ring 10 has an inner diameter smaller than the outer diameter of the outer peripheral surface of the annular groove 210 in the shaft 200 and an outer diameter larger than the inner diameter of the inner peripheral surface of the housing 300 when no external force is applied. It is comprised so that it may become.

In addition, the backup ring 20 according to the present embodiment is provided so as to be in close contact with the low pressure side (L) side surface of the annular groove 210. As a material used for the backup ring 20, a soft resin such as PTFE, or a hard resin such as nylon, PPS (polyphenylene sulfide), POM (polyacetal), PA (polyamide), PEEK (polyether ether ketone), or the like is used. Can do. The backup ring 20 is provided with a cut portion (abutment) at one place in the circumferential direction from the viewpoint of wearability, although not particularly shown. In addition, the back-up ring 20 is not set with a tightening margin on the inner peripheral side or the outer peripheral side. In other words, the backup ring 20 has an inner diameter that is substantially the same as or slightly larger than the outer diameter of the outer peripheral surface of the annular groove 210 in the shaft 200 when no external force is applied, and the outer diameter is the inner peripheral surface of the housing 300. It is configured to be approximately the same as or slightly smaller than the inner diameter of the. This does not interfere with the wearing state. When the pressure is high, the backup ring 20 expands in the radial direction along with the axial compression, so that the inner peripheral surface of the backup ring 20 is in close contact with the outer peripheral surface of the annular groove 210, and the outer peripheral surface is inside the housing 300. Since it is in close contact with the peripheral surface, it fully functions as a backup ring.

  The rubber ring 30 according to the present embodiment is a so-called square ring, which is a high-hardness and high-strength rubber material having a Shore A hardness of 80 degrees or more and 95 degrees or less, and has a hardness higher than that of the seal ring 10. , Having a smaller hardness than that of the backup ring 20, preferably made of a single material. Note that it is desirable to select a rubber material that has resistance to the fluid to be sealed. The rubber ring 30 is not provided with a cut portion (abutment). Further, the rubber ring 30 is configured such that the inner peripheral side has a fastening allowance with respect to the shaft 200 and the outer peripheral side has a fastening allowance with respect to the housing 300. That is, the rubber ring 30 has an inner diameter smaller than the outer diameter of the outer peripheral surface of the annular groove 210 in the shaft 200 in a state where no external force is applied, and the outer diameter is smaller than the inner diameter of the inner peripheral surface of the housing 300. It is configured to be large.

<Use condition of sealing device>
In particular, the usage state of the sealing device 100 according to the present embodiment will be described with reference to FIGS.

  In the sealing device 100 configured as described above, the seal ring 10 is pressed and compressed to the low pressure side (L) when the pressure is high (see FIG. 3), and axially by its own elastic restoring force when there is no load. (See FIG. 2). As a result, the seal ring 10 is in close contact with the entire surface of the high-pressure side (H) of the rubber ring 30 at high pressure, and the seal ring 10 is hardly in contact with the rubber ring 30 at low pressure. It becomes.

  Therefore, when the pressure on the high pressure side (H) pulsates, the state shown in FIG. 2 and the state shown in FIG. 3 are repeated and the seal ring 10 is repeatedly deformed. Therefore, the seal ring 10 is a state in which friction is generated on the outer peripheral side and the inner peripheral side on the low pressure side of the seal ring 10 by continuously repeating the state in which the seal ring 10 is in contact with the rubber ring 30 and the state in which the seal ring 10 is separated. Is considered to occur.

<Excellent point of sealing device according to this embodiment>
The rubber ring 30 according to the present embodiment is configured such that the inner peripheral side has a fastening allowance with respect to the shaft 200 and the outer peripheral side has a fastening allowance with respect to the housing 300. Therefore, the seal ring 10 at high pressure is used. Can be prevented from protruding. Further, since the backup ring 20 is provided on the low pressure side of the rubber ring 30, the protrusion of the rubber ring 30 can be suppressed.

  The seal ring 10 is repeatedly deformed by pressure fluctuation on the high pressure side (in this embodiment, the pulsation in which the pressure periodically fluctuates), and friction appears between the seal ring 10 and the rubber ring 30. Even if such a state occurs, wear of the seal ring 10 can be suppressed as compared with the case where friction occurs between the resin-made backup ring 20 having high hardness. Further, since the rubber ring 30 has a hardness higher than that of the seal ring 10, the wear of the rubber ring 30 itself can be suppressed.

  As described above, even when the sealing device 100 is disposed in an environment in which pressure pulsates on the high pressure side (H), wear of the seal ring 10 can be reduced. Therefore, stable sealing performance can be realized over a long period of time.

When the seal ring 10 is made of a general rubber material, the Shore A hardness is 70 degrees or more and 80 degrees or less as described above. In this case, it is desirable for the rubber ring 30 to set the Shore A hardness to 80 degrees or more and 95 degrees or less as described above. This is because if the hardness of the rubber ring 30 is set to be smaller than this range, the wear of the rubber ring 30 itself is increased, and if it is set to be larger than this range, the effect of suppressing the wear of the seal ring 10 is reduced. Because it will do.

  Further, since the rubber ring 30 is not provided with a cut portion, the pressure distribution on the rubber ring 30 in the seal ring 10 becomes uniform, and generation of uneven wear can be suppressed. In the case of a resin ring, it is generally necessary to provide a cut portion from the viewpoint of wearability. In this case, when the seal ring is in close contact with the resin ring, the pressure distribution is disturbed in the vicinity of the cut portion, resulting in uneven wear.

(Example 2)
4 to 6 show a second embodiment of the present invention. In this embodiment, a modification of the shape of the rubber ring in the sealing device according to the first embodiment will be described. Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  Also in the sealing device 100 according to the present embodiment, as in the case of the first embodiment, the rubber-like elastic seal ring 10, the resin backup ring 20, and the seal ring 10 and the backup ring 20 are provided. The rubber ring 40 is provided between them. Since the seal ring 10 and the backup ring 20 have the same configuration as in the first embodiment, description thereof is omitted.

  And the rubber ring 40 which concerns on a present Example is the structure by which the annular groove | channel 41 was formed in the side surface of the high voltage | pressure side (H) in a square ring. The rubber ring 40 is a high-hardness and high-strength rubber material having a Shore A hardness of 80 degrees or more and 95 degrees or less, as in the case of Example 1, and has a hardness higher than that of the seal ring 10, The back ring 20 has a smaller hardness, preferably a single material. The rubber ring 40 is not provided with a cut portion (abutment). Further, the rubber ring 40 is configured such that the inner peripheral side has a fastening allowance with respect to the shaft 200 and the outer peripheral side has a fastening allowance with respect to the housing 300. That is, the rubber ring 40 has an inner diameter smaller than the outer diameter of the outer peripheral surface of the annular groove 210 in the shaft 200 in a state where no external force is applied, and the outer diameter is smaller than the inner diameter of the inner peripheral surface of the housing 300. It is configured to be large.

  Here, the groove 41 formed in the rubber ring 40 is formed in a shape that conforms to the shape of the low pressure side (L) portion of the seal ring 10 at the time of mounting and no load. That is, the groove 41 has an arc shape in cross section. As a result, the surface of the rubber ring 40 to which the seal ring 10 is in close contact is configured to conform to the shape of the contact surface of the seal ring 10 (when mounted and unloaded).

  With the above configuration, the low-pressure side portion of the seal ring 10 can be fitted into the groove 41 of the rubber ring 40, and even when there is no load, the seal ring 10 and the rubber ring 40 are almost between them. No gap is formed. Therefore, even if the seal ring 10 is repeatedly deformed due to the pulsation on the high pressure side (H), the low pressure side (rubber ring 40 side) portion of the seal ring 10 is hardly deformed.

  Thus, in the sealing device 100 according to the present embodiment, since the deformation of the portion of the contact surface of the seal ring 10 with respect to the rubber ring 30 can be suppressed, the wear of the seal ring 10 compared to the case of the first embodiment. Can be further suppressed.

(Other)
In the above embodiment, the case where the annular groove 210 is provided on the shaft 200 side and the sealing device 100 is mounted on the annular groove 210 has been described as an example. However, the annular groove is provided on the housing 300 side, and the annular groove is provided. It is also possible to adopt a configuration in which a sealing device is attached to the.

DESCRIPTION OF SYMBOLS 10 Seal ring 20 Backup ring 30,40 Rubber ring 41 Groove 100 Sealing device 200 Shaft 210 Annular groove 300 Housing

Claims (3)

In a sealing device that is mounted in an annular groove provided in one of the two members and seals the annular gap between the two members,
A rubber-like elastic seal ring mounted in the annular groove;
A resin-made backup ring provided in close contact with the low-pressure side surface of the annular groove;
Provided between the seal ring and the backup ring, both the inner peripheral side and the outer peripheral side are set to have a tightening margin with respect to the two members, and the hardness is larger than the seal ring, And a rubber ring with low hardness,
A sealing device comprising:   2. The sealing device according to claim 1, wherein a surface of the rubber ring to which the seal ring comes into close contact is configured to conform to a shape of the contact surface of the seal ring.   The sealing device according to claim 1, wherein the sealing device is disposed in an environment in which pressure pulsates on a high pressure side.

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