JP2012180910A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device that suppresses reduction in sealing performance to be caused by changes in temperature.SOLUTION: The sealing device includes a seal ring 1 and a seal ring 2. The seal ring 1 is made of resin, mounted on an annular groove 40 formed on a shaft 4, and tightly adhering to a side face 41 of the annular groove 40 and a circumferential face of a shaft hole 30. The seal ring includes a separated part S1 at a position on the perimeter thereof and a circumferential groove 10 extending in a circumferential direction on a circumferential face adhering to the circumferential face of the shaft hole 30. The second seal ring 2 is made of resin, is mounted on the circumferential groove 10, and tightly adhering to a side face 10a of the circumferential groove 10 and the circumferential face of the shaft hole 30. The second seal ring 2 includes a separated part S2 at a position on the perimeter thereof. The ends of the separated part S2 face to each other with a gap formed between terminal side faces 10b, 10c of the circumferential groove 10 to absorb changes in perimeter length to be caused by changes in temperature.

Description

  The present invention relates to a sealing device.

  Conventionally, a resin seal ring is known as a sealing device for sealing an annular gap between a shaft hole of a housing and a shaft inserted through the shaft hole (see, for example, Patent Document 1).

  A seal ring according to a conventional example will be described with reference to FIG. FIG. 6 is a schematic diagram for explaining a seal ring according to a conventional example, (A) is a schematic perspective view showing a configuration of a separating portion, (B) is a schematic cross-sectional view (without pressure) of the seal ring, (C) is a schematic sectional view of the seal ring (when blow-through occurs), respectively.

  As shown in FIG. 6 (A), the seal ring 100 is formed into a shape that is cut at one place on the circumference in order to facilitate attachment to the annular groove 301. The seal ring 100 is attached to the annular groove 301 by deforming the cut portion (separation portion) 101 so as to expand. The seal ring 100 receives pressure acting from the region to be sealed, is pressed against the side surface 302 of the annular groove 301, expands in diameter, and is brought into close contact with the shaft hole 201 to exhibit sealing performance.

  As shown in FIG. 6B, the seal ring 100 is in a state in which a gap is formed between the shaft hole 201 and the outer peripheral surface when there is no pressure action or when the pressure is extremely low. The seal ring 100 is brought into close contact with the shaft hole 201 and forms a sealed state by the pressure P acting and expanding and deforming. Therefore, the end portions (separation end portions) of the seal ring 100 formed by providing the cut portions 101 are in a state of facing each other with a space therebetween when pressurized. The seal ring 100 is expanded or contracted so as to widen or fill the gap between the end portions, thereby absorbing a dimensional error with respect to the mounting partner, an eccentricity of the shaft, and the like. The contact state between the hole 201 and the groove side surface 302 of the annular groove 301 of the shaft 300 can be maintained.

  By the way, the seal ring 100 made of a resin material has a property that the circumference changes due to the expansion / contraction of the resin material due to the temperature change of the use environment. Therefore, when the temperature of the seal ring 100 is increased under high temperature conditions, the circumference may be extended and the ends may be in contact with each other. If it continues to be used in this state, a permanent strain (plastic deformation state) is generated by generating a circumferential compressive force in the vicinity of the cut portion 101. When such creep deformation occurs, the circumferential length of the seal ring 100 when the room temperature or low temperature condition is reached is shortened.

  The seal ring 100 having a short circumference and deformed with time deteriorates the responsiveness in the initial stage of pressurization, that is, the time until the diameter of the seal ring 100 expands and comes into contact with the shaft hole 201 (until the sealing function is exhibited). Becomes longer. This reduction in responsiveness causes a large amount of leakage of the fluid to be sealed at the initial stage of pressurization called so-called blow-through leakage, and also leads to a decrease in control accuracy of the fluid to be sealed. Further, since the gap between the cut portions 101 is enlarged due to the deformation, the amount of leakage after the seal ring 100 comes into contact with the shaft hole 201 also increases.

  As described above, the sealing ring made of resin may deteriorate in sealing performance due to a temperature change, and as a result, there is a concern that various adverse effects may be exerted on the wearing counterpart device.

Japanese Patent No. 3362099

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a sealing device capable of suppressing a decrease in sealing performance due to a temperature change.

In order to achieve the above object, a sealing device according to the present invention comprises:
A sealing device for sealing an annular gap between a shaft hole provided in a housing and a shaft inserted through the shaft hole,
A resin seal ring that is mounted in an annular groove provided in one of the shaft and the shaft hole, and is in close contact with the side surface of the annular groove and the other peripheral surface of the shaft or the shaft hole. A first seal ring including a circumferential groove extending in the circumferential direction on a circumferential surface closely contacting the other circumferential surface, and having a separation portion at one place on the circumference;
A resin sealing ring having a separation portion at one place on the circumference, being attached to the circumferential groove, and being in close contact with a side surface of the circumferential groove and the other circumferential surface, the separation end portion being A second seal ring opposed to the end side surface of the circumferential groove with a gap capable of absorbing a change in circumference due to a temperature change;
It is characterized by providing.

  According to such a configuration, even when the circumference of the second seal ring is extended under use in a high temperature environment, the end portion does not hit the terminal side surface of the circumferential groove, and the creep deformation as described above is not caused. Does not occur. Therefore, even when the sealing performance of the first seal ring is reduced due to the influence of temperature change, that is, the creep deformation as described above, the sealing performance of the entire sealing device is maintained by the second sealing ring maintaining the sealing performance. Can be suppressed.

  According to the present invention, it is possible to suppress a decrease in sealing performance due to a temperature change.

The typical sectional view of the sealing device concerning the example of the present invention. The typical sectional view showing the behavior of the seal ring at the time of the pressurization initial stage. The schematic diagram which shows the structure of a 1st seal ring. The schematic diagram which shows the structure of a 2nd seal ring. The typical perspective view which shows the mode of the isolation | separation part vicinity. The schematic diagram explaining the seal ring which concerns on a prior art 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)
With reference to FIGS. 1-5, the sealing device based on the Example of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a sealing device according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing the behavior of the seal ring in the initial stage of pressurization of the sealing device according to the present embodiment. 3A and 3B are schematic views showing the configuration of the first seal ring, where FIG. 3A is a view seen from the axial direction, and FIG. 4A and 4B are schematic views showing the configuration of the second seal ring, where FIG. 4A is a view seen from the axial direction, and FIG. FIG. 5 is a schematic perspective view showing a state in the vicinity of the separation portion.

<Schematic configuration of sealing device>
As shown in FIG. 1, the sealing device according to this embodiment is for sealing an annular gap 5 between a shaft hole 30 provided in the housing 3 and a shaft 4 inserted through the shaft hole 30. It is.

  The sealing device according to this embodiment includes a first seal ring 1 and a second seal ring 2. The first seal ring 1 is mounted in an annular groove 40 provided on the outer peripheral surface of the shaft 4. The first seal ring 1 has a circumferential groove 10 extending in the circumferential direction on the outer peripheral surface, and the second seal ring 2 is mounted in the circumferential groove 10 of the first seal ring 1.

  As shown in FIG. 2, due to the pressure P acting from one side in the axial direction, the outer peripheral surface 11 of the first seal ring 1 is in close contact with the shaft hole 30 of the housing 3, and the side surface 12 is the side surface of the annular groove 40 of the shaft 4. 41. In addition, the outer peripheral surface 20 of the second seal ring 2 is in close contact with the shaft hole 30 of the housing 3, and the side surface 21 is in close contact with the side surface 10 a of the circumferential groove 10 of the first seal ring 1. Thereby, the annular gap 5 is sealed by the sealing device, that is, the non-sealing target region side (axis) from the sealing target region side (one axial direction side) on which the fluid pressure of the sealing target fluid acts in the annular gap 5. Leakage of the fluid to be sealed to the other side in the direction is prevented.

  The fluid to be sealed is, for example, lubricating oil, and particularly refers to ATF (automatic transmission fluid) when used in an automobile transmission.

<First seal ring>
As shown in FIG. 3, the first seal ring 1 has a substantially ring shape provided with a separation portion S <b> 1 at one place on the circumference. The first seal ring 1 is formed from a resin material. Examples of the resin material include PEEK and PPS.

<< Separation part >>
The separation part S1 is provided for the purpose of improving the assemblability of the first seal ring 1 or the like. As a form of the separation part S1 of the seal ring 1, a two-step special step cut which is a conventional technique is adopted. The configuration of the special step cut is a prior art and will be described briefly.

  In the separation portion S1, the seal ring 1 is provided with a pair of left and right (axial) arc-shaped convex portions 14 and arc-shaped concave portions 15 on the outer peripheral side of one separation end portion 13a, and the other separation end portion 13b A pair of left and right arc-shaped convex portions 16 and arc-shaped concave portions 17 are also provided on the outer peripheral side. And when the convex part 14 and the recessed part 17 fit, and the convex part 16 and the recessed part 15 fit, the isolation | separation part S1 will be in the closed state, and the seal ring 1 will become an annular shape.

  In a state where the separation portion S1 is closed, between the convex portion 14 and the concave portion 17, between the convex portion 16 and the concave portion 15, and an inner peripheral side end surface of the separation end portion 13a and an inner peripheral side end surface of the separation end portion 13b. Gap G1, G2, and G3 are formed between the two. Further, the convex portion 14 and the concave portion 17 are slidably in contact with each other on a separation surface concentric with the peripheral surface of the first seal ring 1 and a separation surface perpendicular to the axis. Similarly, the convex portion 16 and the concave portion 15 are slidably in contact with each other on a separation surface concentric with the peripheral surface of the first seal ring 1 and a separation surface perpendicular to the axis.

  Thus, even if the said clearance gaps G1-G3 are formed because each isolation | separation surface is mutually slidably contacted, the contact surface (seal | sticker) with the other member of the 1st seal ring 1 in isolation | separation part S1. The portion where the surface) is interrupted is not formed. That is, in the separation portion S1, even if the surfaces perpendicular to the circumferential direction are spaced apart from each other in the circumferential direction, the sealing target side and the non-sealing target side can be blocked.

  Moreover, the 1st seal ring 1 can increase / decrease a ring diameter by sliding in the circumferential direction so that each convex part and a recessed part may expand or fill the above-mentioned clearance gaps G1, G2, G3. As a result, errors in the diameter between the first seal ring 1 and the shaft hole 30, eccentricity of the shaft 4 with respect to the housing 3, elongation of the circumferential length of the ring body 10 due to thermal expansion, and the like are indicated by gaps G1, G2, Only G3 can be absorbed.

  The seal ring having the separation part as in the above configuration is created by first creating an annular ring body and cutting one part of the ring body into the step shape using a dedicated jig. In some cases, it may be molded into a shape that is separated from the beginning (in the state in which the step shape is formed).

  Various other types of separation portions are known, and may be a straight type as shown in FIG. 5, that is, a simple end surface shape having no stepped complex irregularities.

<< Circumferential groove >>
The circumferential groove 10 extends in the circumferential direction on the outer peripheral surface 11 of the first seal ring 1. The circumferential groove 10 terminates in the vicinity of one separation end portion 13a and the other separation end portion 13b, and has side surfaces 10a extending in the circumferential direction and termination side surfaces 10b, 10c perpendicular to the circumferential direction. .

<Second seal ring>
As shown in FIG. 4, the second seal ring 2 has a substantially ring shape provided with a so-called straight type separation portion S <b> 2 at one place on the circumference. Separation end faces 22a and 22b perpendicular to the circumferential direction are formed in the separation part S2. The second seal ring 2 is formed from a resin material. Examples of the resin material include PEEK and PPS.

  As shown in FIG. 5, in the state where the second seal ring 2 is mounted in the circumferential groove 10, the separation end surfaces 22a and 22b of the separation portion S2 and the end side surfaces 10b and 10c of the circumferential groove 10 are interposed via a gap. Facing each other in the circumferential direction. That is, the circumferential length of the second seal ring 2 is set shorter than the length (circumferential length) of the circumferential groove 10.

  The gaps between the separation end surfaces 22a and 22b and the terminal side surfaces 10b and 10c are provided so as to absorb the change in the circumferential length of the second seal ring due to the temperature change. That is, the circumferential length of the second seal ring 2 is set so that the circumferential length in a state where thermal expansion has occurred is shorter than the length (circumferential length) of the circumferential groove 10. Thereby, even if thermal expansion occurs, a gap having a size that does not allow the separation end surfaces 22a and 22b to abut against the end side surfaces 10b and 10c of the circumferential groove 10 is formed between the separation end surfaces 22a and 22b and the end side surfaces 10b and 10c. It is formed.

  In setting the circumference of the second seal ring 2, for example, the thermal expansion coefficient of the resin material of the first seal ring 1, the thermal expansion coefficient of the resin material of the second seal ring 2, and the temperature change of the use environment are taken into consideration. The

<Excellent points of this embodiment>
According to the present embodiment, even if the circumference of the second seal ring is extended under use in a high temperature environment, the end portion does not come into contact with the end side surface of the circumferential groove. Therefore, by continuing to be used in a state where the end portion is in contact with the end side surface of the circumferential groove, it is possible to prevent creep deformation that shortens the circumferential length of the seal ring.

  Therefore, even if the sealing performance of the first seal ring (responsibility at the time of pressurization) decreases due to the influence of temperature change, that is, creep deformation as described above, the second seal ring maintains the sealing performance. And the fall of the sealing performance as the whole sealing device can be controlled.

  Here, with reference to FIG. 2, the behavior of the sealing device during pressurization, that is, the behavior of each seal ring will be described. Here, when the circumference of the first seal ring extends beyond the gaps G1 to G3 in the separation part S1 due to use in a high temperature environment, the end parts come into contact with each other, resulting in creep deformation. Assuming that the circumference of the first seal ring 1 is shortened at room temperature or low temperature.

  As shown in the left cross-sectional view of FIG. 2, when the pressure P starts to be applied from the sealing target region side of the annular gap 5, first, the second seal ring 2 is connected to the circumferential surface of the axial hole 30 and the circumferential groove 10. 10a is brought into close contact with each other. The first seal ring 1 has reduced responsiveness due to a decrease in circumferential length due to creep deformation, and a seal surface cannot be formed at this point. The seal range (peripheral length of the contact surface) with the shaft hole 30 formed by the second seal ring 2 is shorter than the seal range of the first seal ring 1 (the gap in the separation portion is large), except for the vicinity of the separation portion. Since the sealing function of the second seal ring 2 is exhibited, the leakage can be greatly reduced as compared with the case where a large amount of blow-through leakage that is a concern with the first seal ring 1 is generated.

  Then, as shown in the right sectional view of FIG. 2, when a certain amount of time elapses from the initial stage of pressurization, the first seal ring 1 is also deformed in diameter to form a seal surface. As a result, there is no gap in the vicinity of the separating portion, and the original sealing performance of the sealing device is exhibited.

  As described above, even when the responsiveness of the first seal ring 1 is lowered, that is, when the time until the sealing function is exhibited becomes longer, the sealing performance as designed is exhibited for the second seal ring 2. As a result, the influence of a decrease in the sealing performance of the first seal ring 1, for example, the occurrence of blowout leakage is suppressed. Therefore, it is possible to suppress an adverse effect on the wearing counterpart device, for example, a decrease in control accuracy of the sealing target fluid.

<Others>
In this embodiment, the configuration in which the sealing device is mounted in the annular groove 40 provided on the outer peripheral surface of the shaft 4 has been described. However, the sealing device is installed in the annular groove provided in the peripheral surface of the shaft hole 30 of the housing 3. The inner peripheral surface of this may slide with the outer peripheral surface of the shaft 4 to seal the annular gap 5.

  Moreover, the kind of the resin material of the 1st seal ring 1 and the 2nd seal ring 2 may be the same, and may mutually differ. That is, even when thermal expansion occurs under high temperature conditions, various materials can be arbitrarily selected as long as the second seal ring 2 can maintain a desired sealing property as described above.

  Moreover, the 2nd seal ring 2 may be the structure which was divided | segmented into the some circular-arc-shaped member instead of one substantially ring shape as mentioned above, for example.

DESCRIPTION OF SYMBOLS 1 1st seal ring 10 Circumferential groove 11 Outer peripheral surface 11a Side surface 11b, 11c End side surface 12 Side surface 13a, 13b End 2 Second seal ring 20 Outer peripheral surface 21 Side surface 22a, 22b End surface 3 Housing 30 Shaft hole 4 Shaft 40 Annular groove 41 Side surface 5 Annular gap

Claims (1)

A sealing device for sealing an annular gap between a shaft hole provided in a housing and a shaft inserted through the shaft hole,
A resin seal ring that is mounted in an annular groove provided in one of the shaft and the shaft hole, and is in close contact with the side surface of the annular groove and the other peripheral surface of the shaft or the shaft hole. A first seal ring including a circumferential groove extending in the circumferential direction on a circumferential surface closely contacting the other circumferential surface, and having a separation portion at one place on the circumference;
A resin sealing ring having a separation portion at one place on the circumference, being attached to the circumferential groove, and being in close contact with a side surface of the circumferential groove and the other circumferential surface, the separation end portion being A second seal ring opposed to the end side surface of the circumferential groove with a gap capable of absorbing a change in circumference due to a temperature change;
A sealing device comprising:

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