JP2020045955A - Seal ring - Google Patents

Abstract

To provide a seal ring capable of further effectively reducing a friction loss.SOLUTION: A seal ring is equipped with an outer peripheral surface, an inner peripheral surface, a side surface, and a plurality of pockets. The outer peripheral surface includes: a flat portion which turns outward in a diametrical direction, and is positioned at a center portion in a thickness direction; and an inclined portion which inclines from the flat portion outward in the thickness direction and inward in the diametrical direction. The inner peripheral surface turns inward in the diametrical direction. The side surface turns outward in the thickness direction. The plurality of pockets is provided on the side surface at intervals. The outer peripheral side is blocked and the inner peripheral surface side is opened.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a seal ring that can be used for a hydraulic device or the like.

  A seal ring is used for various hydraulic devices such as a hydraulic automatic transmission mounted on a vehicle. The seal ring is fitted into a groove of a shaft inserted into the housing, and seals between the housing and the shaft. Thus, oil leakage between the shaft and the housing can be prevented.

  There are two types of seal rings having different sliding surfaces when the shaft and the housing rotate relative to each other. That is, the seal ring includes a side sliding type in which the side rotates with the housing and the side slides with respect to the groove of the shaft, and an outer peripheral surface sliding type in which the seal ring rotates with the shaft and the outer peripheral surface slides with the housing. , Exists.

  In the seal ring of the outer peripheral surface sliding type, the abutment portion is opened as the abrasion of the outer peripheral surface proceeds, so that oil leakage at the abutment portion is likely to occur. On the other hand, in the side-sliding type seal ring, the sealing performance is hardly impaired even if the side surface wears. Therefore, high durability can be obtained with the side-sliding type seal ring.

  Hydraulic equipment is required to reduce drive loss from the viewpoint of energy saving. For this reason, seal rings used in hydraulic equipment are required to reduce friction loss. Patent Literatures 1 to 6 disclose a side-sliding type seal ring in which friction loss between a side surface and a shaft is reduced.

  The seal rings described in Patent Literatures 1 to 6 have a plurality of pockets that are provided at intervals on the side surface, the outer peripheral surface side is closed, and the inner peripheral surface side is open. In such a seal ring, the pressing force is applied in a direction in which the side surface is separated from the shaft by the oil pressure of the oil that has entered the pocket from the inner peripheral surface side, so that friction loss is reduced.

  In particular, in the seal ring described in Patent Document 1, by providing a pocket designed to take into consideration the behavior of oil in the pocket when the shaft and the housing rotate relative to each other, a greater pressing force is received from the oil. Can be. Thereby, friction loss between the side surface and the shaft is significantly reduced.

WO 2016/158848 pamphlet International Publication No. 2011/105513 pamphlet WO 2004/090390 pamphlet International Publication No. 2011/162283 pamphlet International Publication No. WO 2013/096544 pamphlet International Publication No. WO 2013/094657 pamphlet

  Actually, the outer peripheral surface of the side-sliding type seal ring does not stick to the housing when the shaft and the housing rotate relative to each other. I have. Therefore, in the side-sliding type seal ring, a slight friction loss occurs between the outer peripheral surface and the housing.

  As described above, in the side-sliding type seal ring, the technology for reducing the friction loss between the side surface and the shaft has been matured. In this situation, in the side-sliding type seal ring, reduction of friction loss between the outer peripheral surface and the housing may be effective for further reducing friction loss as a whole.

  In view of the circumstances described above, an object of the present invention is to provide a seal ring that can reduce friction loss more effectively.

In order to achieve the above object, a seal ring according to one embodiment of the present invention includes an outer peripheral surface, an inner peripheral surface, a side surface, and a plurality of pockets.
The outer peripheral surface includes a flat portion facing outward in the radial direction, and an inclined portion inclined inward in the radial direction from the flat portion toward the outside in the thickness direction.
The inner peripheral surface faces the inside in the radial direction.
The side surface faces outward in the thickness direction.
The plurality of pockets are provided at intervals on the side surface, the outer peripheral surface side is closed, and the inner peripheral surface side is open.

  In this seal ring, the friction loss between the side surface and the shaft is reduced by the action of the plurality of pockets, and the friction loss between the outer peripheral face and the housing is reduced by the action of the inclined portion of the outer peripheral face. This makes it possible to provide a seal ring that can reduce friction loss more effectively.

The flat portion may be located at a central portion in the thickness direction.
The seal ring may further include an abutting portion and a main body extending annularly between the abutting portions. In this case, the inclined portion may not be formed at the abutment. The inclined portion may be formed continuously over the entire circumference of the main body.
The inclined portion may include a plurality of inclined portions formed at intervals from each other.
An angle between the cylindrical surface having the flat portion extended in the thickness direction and the inclined portion may be 25 ° or less.
The size of the flat portion in the thickness direction may be 3% or more and 80% or less of the size of the outer peripheral surface in the thickness direction.
The radial dimension of the inclined portion may be 16% or less of a distance between the flat portion and the inner peripheral surface.
With these configurations, the friction loss between the outer peripheral surface and the housing can be further effectively reduced.

  A seal ring capable of more effectively reducing friction loss can be provided.

It is a top view of the seal ring concerning one embodiment of the present invention. FIG. 3 is a partial perspective view of the seal ring. It is a fragmentary perspective view showing other embodiments of the above-mentioned seal ring. FIG. 2 is a cross-sectional view of the seal ring taken along line AA ′ of FIG. 1. It is a top view showing other embodiments of the above-mentioned seal ring. It is sectional drawing which shows other embodiment of the said seal ring. It is sectional drawing which shows other embodiment of the said seal ring. It is sectional drawing which shows the state in which the said seal ring was integrated with the shaft and the housing. FIG. 4 is a cross-sectional view of a seal ring according to Comparative Example 1. 4 is a graph showing evaluation results of drag torque of the seal ring according to the example. 4 is a graph showing evaluation results of drag torque of the seal ring according to the example. 4 is a graph showing evaluation results of drag torque of the seal ring according to the example. FIG. 9 is a cross-sectional view of a seal ring according to Comparative Example 2. It is sectional drawing which shows other embodiment of the said seal ring. It is sectional drawing which shows other embodiment of the said seal ring.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[Seal ring 1]
FIG. 1 is a plan view of a seal ring 1 according to one embodiment of the present invention. The seal ring 1 has a main body 1a and an abutment 1b. The main body 1a is formed in an annular shape around the central axis C. The abutment 1b constitutes both ends of the main body 1a. That is, the main body 1a extends annularly between the abutments 1b.

  The abutment portions 1b are configured to be mutually engageable in the circumferential direction. In the seal ring 1, the diameter of the main body 1a can be increased by expanding the abutment 1b in the circumferential direction while elastically deforming the main body 1a. Thus, the seal ring 1 can be easily mounted on a shaft member having a large diameter.

  The outer surface of the main body 1a of the seal ring 1 includes an outer peripheral surface 2, an inner peripheral surface 3, and a pair of side surfaces 4. The outer peripheral surface 2 faces outward in a radial direction which is a direction of an axis orthogonal to the central axis C. The inner peripheral surface 3 faces inward in the radial direction. The side surface 4 faces outward in the thickness direction which is the direction of an axis parallel to the central axis C. The outer peripheral surface 2 includes a flat part 21 and an inclined part 22.

  The flat portion 21 of the outer peripheral surface 2 is a cylindrical surface centered on the central axis C. The inner peripheral surface 3 is a cylindrical surface centered on the central axis C. The side surface 4 is a plane parallel to a plane orthogonal to the central axis C. The main body 1a typically has a shape orthogonal to the central axis C and symmetric in the thickness direction with respect to a plane passing through the center in the thickness direction.

  It is preferable that the abutment portion 1b has a configuration in which a gap is hardly generated in order to prevent oil leakage. The abutment 1b is not limited to a specific configuration, and may employ, for example, a right angle (straight) abutment, an oblique (angle) amalgamation, a stepped (step) amalgamation, a double angle amalgamation, a double cut amalgamation, a triple step amalgamation, and the like. It is.

  The seal ring 1 is attached to the groove 111 of the shaft 110 in a state where the abutment portion 1b is slightly widened and the main body portion 1a is expanded in diameter. The outer peripheral surface 2 of the seal ring 1 mounted on the shaft 110 slightly protrudes from the groove 111 of the shaft 110. Then, the shaft 110 is inserted into the housing 120 with the seal ring 1 mounted (see FIG. 4).

  A plurality of pockets 10 that are recessed in the thickness direction are provided on the side surface 4 of the seal ring 1. The plurality of pockets 10 are arranged at equal intervals at positions on the inner peripheral surface 3 side of both side surfaces 4. In the seal ring 1, the friction loss between the side surface 4 and the shaft 110 can be reduced by the action of the plurality of pockets 10.

  FIG. 2 is a partial perspective view of the seal ring 1 showing the vicinity of the pocket 10 in an enlarged manner. The configuration of the pocket 10 will be described with reference to FIG. The pocket 10 is open to the inner peripheral surface 3 side of the seal ring 1. Therefore, in the seal ring 1, oil can flow into the pocket 10 from the inner peripheral surface 3 side.

  On the other hand, the pocket 10 has a partition 13 that forms the side surface 4 of the seal ring 1 between itself and the outer peripheral surface 2, and the outer peripheral surface 2 side is closed by the partition 13. Therefore, in the seal ring 1, it is possible to suppress the oil flowing into the pocket 10 from the inner peripheral surface 3 side from leaking to the outer peripheral surface 2 side.

  On the side surface 4 of the seal ring 1, between the plurality of pockets 10, there is provided a pillar portion 14 that forms the side surface 4 together with the partition wall portion 13. That is, the pockets 10 and the pillars 14 are alternately arranged in the seal ring 1 along the circumferential direction. Each pocket 10 is separated by a pillar 14 in the circumferential direction of the seal ring 1.

  The pocket 10 has a bottom 11 and a slope 12. The bottom portion 11 is provided at a circumferentially central portion of the pocket 10. The slope 12 is provided on both sides of the pocket 10 in the circumferential direction. The slope 12 is inclined from the bottom 11 toward the column 14 such that the depth from the side surface 4 decreases.

  The bottom 11 constitutes the bottom surface of the pocket 10 deepest from the side surface 4. That is, the pocket 10 has the widest opening toward the inner peripheral surface 3 at the bottom 11. Therefore, oil mainly flows into the pocket 10 from the bottom 11. The bottom 11 is typically planar, but is not limited to this configuration, and may be, for example, a gently curved surface.

  The slope 12 is typically a series of planes, but may be inclined so that the depth from the side surface 4 decreases from the bottom 11 toward the pillar 14. For example, as shown in FIG. 3, the slope 12 may be composed of a plurality of planar slopes 12a and 12b having different inclination angles. That is, in the slope portion 12, the angle of inclination may change in the middle of the circumferential direction.

  In addition, the slope 12 may be formed of three or more planar slopes having different inclination angles. Furthermore, the slope 12 may have a continuously changing angle of inclination along the radial direction. That is, the slope 12 may be entirely or partially formed of a gentle curved surface having a convex or concave shape.

  FIG. 4 is a cross-sectional view of the seal ring 1 taken along line AA ′ of FIG. That is, FIG. 4 shows a cross section of the seal ring 1 cut along the radial direction and the thickness direction at the position of the bottom 11 of the pocket 10. With reference to FIG. 4, the configuration of the flat portion 21 and the inclined portion 22 of the outer peripheral surface 2 will be described.

  The flat portion 21 is a cylindrical surface provided at the center in the thickness direction and centered on the central axis C. The inclined portions 22 are provided on both sides of the flat portion 21 in the thickness direction, and are inclined radially inward toward the outside in the thickness direction. That is, the portion of the inclined portion 22 closer to the side surface 4 is closer to the inner peripheral surface 3.

  As shown in FIG. 1, it is preferable that the inclined portion 22 is not formed at the abutment portion 1b. As a result, oil leakage at the joint 1b can be reduced. In addition, it is preferable that the inclined portion 22 is formed continuously over the entire circumference of the main body 1a. Thereby, the effect of providing the later-described inclined portion 22 can be more effectively obtained.

  The configuration of the inclined portion 22 is not limited to the above. For example, as shown in FIG. 5, the seal ring 1 may have a plurality of inclined portions 22 divided in the circumferential direction. In the seal ring 1 having such a configuration, since the flat portion 21 extends over the entire width of the outer peripheral surface 2 in the column portion 24 formed between the plurality of inclined portions 22, it is easy to maintain a stable posture during use.

  The inclined portion 22 forms a side surface of a truncated cone around the central axis C, and has a series of linear cross-sectional shapes that form an angle α with a cylindrical surface that extends the flat portion 21 in the thickness direction. However, the configuration of the inclined portion 22 is not limited to this. For example, the inclined portion 22 may not have a conical surface, that is, may have a curved cross-sectional shape or a bent linear cross-sectional shape (multi-step inclination).

  For example, the inclined portion 22 may have a cross-sectional shape of a convex curve as shown in FIG. 6A, or may have a cross-sectional shape of a concave curve as shown in FIG. 6B. Further, the cross section of the inclined portion 22 may have a shape in which two or more of a straight line, a convex curve, and a concave curve are combined. As shown in FIGS. 6A and 6B, the angle α of the inclined portion 22 that is not such a conical surface is obtained by extending the conical surface passing through both ends in the thickness direction of the inclined portion 22 and the flat portion 21 in the thickness direction. It is defined as the angle between the cylindrical surface.

  FIG. 7 is a cross-sectional view showing a state where the seal ring 1 is incorporated in the shaft 110 and the housing 120. The shaft 110 is provided with a groove 111 over the entire outer peripheral surface. The shaft 110 is inserted through the housing 120 with the seal ring 1 fitted in the groove 111.

  In the state shown in FIG. 7, oil flows into the gap between the shaft 110 and the housing 120 from the right side. At this time, the right side surface 4 is pressed by the oil, and the left side surface 4 is pressed against the side wall of the groove 111 of the shaft 110. Further, the inner peripheral surface 3 is pressed by the oil, and the flat portion 21 of the outer peripheral surface 2 is pressed against the inner peripheral surface of the housing 120.

  Thereby, the gap between the shaft 110 and the housing 120 is sealed, and it is possible to prevent oil from leaking to the left side of the seal ring 1. Further, in the seal ring 1, since the main body portion 1a is formed symmetrically in the thickness direction, the same function can be obtained when the main body portion 1a is fitted in the groove portion 111 of the shaft 110 right and left opposite.

  In addition, the seal ring 1 is of a side-sliding type and is configured to rotate mainly with respect to the shaft 110. For example, in the seal ring 1, when the shaft 110 and the housing 120 rotate relatively, the rotation with respect to the shaft 110 is almost the same, and the rotation with respect to the housing 120 is only a few%.

  Therefore, in the seal ring 1, the side surface 4 that contacts the shaft 110 is a main sliding surface, and the outer peripheral surface 2 that contacts the housing 120 is a sub sliding surface. In the seal ring 1, as a major premise for reducing the friction loss as a whole, it is necessary to reduce the friction loss between the side surface 4, which is the main sliding surface, and the shaft 110.

  In the seal ring 1, friction loss between the side surface 4, which is the main sliding surface, and the shaft 110 can be reduced by the action of the plurality of pockets 10. Specifically, in the state shown in FIG. 7, the left pocket 10 closed from the right by the shaft 110 has an action of reducing friction loss between the side surface 4 and the shaft 110.

  More specifically, the seal ring 1 receives a pressing force in a direction in which the side surface 4 is separated from the shaft 110 by the oil pressure of the oil in the left pocket 10. Thereby, the normal force between the side surface 4 and the shaft 110 is reduced. Therefore, friction loss between the side surface 4 and the shaft 110 is reduced.

  In addition, in the seal ring 1, the friction loss between the side surface 4 and the shaft 110 can be further reduced by using the energy of the oil flowing in the pocket 10 in addition to the action by the oil pressure in the pocket 10. In order to obtain such an effect, the seal ring 1 is provided with a bottom 11 and a slope 12 shown in FIG.

  In the seal ring 1, when the shaft 110 and the housing 120 rotate relative to each other, the oil enters the pocket 10 from the bottom 11 and passes through the pocket 10 to one of the slopes 12 according to the rotation direction. Flow toward. As a result, in the seal ring 1, a circumferential pressing force of a magnitude corresponding to the flow rate of the oil is applied to the inclined surface portion 12.

  In the seal ring 1, a circumferential pressing force applied from the oil to the inclined surface 12 acts in a direction to separate the side surface 4 from the shaft 110. Thereby, the normal force between the side surface 4 and the shaft 110 is further reduced. Therefore, the friction loss between the side surface 4 and the shaft 110 is further reduced.

  In addition, it is preferable that the connection part which connects the bottom part 11 and the slope part 12 is a concave R surface depressed from the side surface 4 side. As a result, the oil flows smoothly from the bottom 11 to the slope 12 and the flow velocity of the oil is less likely to be impaired. Therefore, the pressing force applied to the slope 12 from the oil can be further increased.

  In addition, it is preferable that the connecting portion connecting the slope portion 12 and the pillar portion 14 is a convex R surface protruding toward the side surface 4. Accordingly, in the connection portion, an oil flow path is formed in which the throttle becomes smaller as approaching the column portion 14, and the oil easily enters the depth on the column portion 14 side, so that the pressing force received from the oil is increased. Can be.

  As described above, in the seal ring 1, the friction loss between the side surface 4 and the shaft 110 is sufficiently reduced. In the seal ring 1 according to the present embodiment, in order to further reduce the friction loss as a whole, the friction loss between the outer peripheral surface 2 which is the sub sliding surface and the housing 120 is reduced.

  In the seal ring 1, the friction loss between the outer peripheral surface 2, which is the sub sliding surface, and the housing 120 can be reduced by the action of the inclined portion 22 of the outer peripheral surface 2. Specifically, in the state shown in FIG. 7, the right inclined portion 22 into which the oil flows has an action of reducing friction loss between the outer peripheral surface 2 and the housing 120.

  More specifically, in the seal ring 1, the right inclined portion 22 receives a pressing force in an oblique direction indicated by a block arrow in FIG. In the seal ring 1, the pressing force applied to the inclined portion 22 from the oil has a component in a direction of separating the outer peripheral surface 2 from the housing 120.

  Therefore, in the seal ring 1, the vertical force between the flat portion 21 and the housing 120 is reduced by the pressing force applied to the inclined portion 22 from the oil. Thereby, in the seal ring 1, the frictional force applied when the flat portion 21 slides on the housing 120 is reduced, so that the friction loss between the flat portion 21 and the housing 120 is reduced.

  Further, by reducing the friction loss between the outer peripheral surface 2 and the housing 120, a synergistic effect that the friction loss between the side surface 4 and the shaft 110 is further reduced is obtained. Thereby, in the seal ring 1, the friction loss as a whole can be further reduced.

  FIG. 4 shows the angle α of the inclined portion 22 with respect to the cylindrical surface obtained by extending the flat portion 21 in the thickness direction. As the angle α of the inclined portion 22 is smaller, the component of the pressing force applied from the oil to the inclined portion 22 in the direction in which the outer peripheral surface 2 is separated from the housing 120 is increased. Therefore, the angle α of the inclined portion 22 is preferably equal to or less than 25 °, more preferably 5 °, and further preferably 1 °.

  FIG. 4 shows a dimension T of the seal ring 1 in the thickness direction and a dimension T1 of the flat portion 21 in the thickness direction. In order to reduce the friction loss between the flat portion 21 and the housing 120, the dimension T1 is preferably small. On the other hand, if the dimension T1 is too small, it is difficult to ensure the sealing performance between the flat portion 21 and the housing 120.

  Therefore, the ratio of the dimension T1 of the flat portion 21 to the dimension T of the seal ring 1 is preferably 3% or more and 80% or less, more preferably 5% or more and 50% or less, and is 22%. Is more preferred. Thereby, in the seal ring 1, it is possible to reduce the friction loss between the flat portion 21 and the housing 120 while sufficiently securing the sealing performance.

  Further, FIG. 4 shows a radial dimension D of the seal ring 1 and a radial dimension D1 of the inclined portion 22 which are defined as a distance between the flat portion 21 and the inner peripheral surface 3. In the seal ring 1, the friction loss is reduced by securing a certain contact area of the side surface 4 with the shaft 110 and effectively obtaining the dynamic pressure effect.

  In this regard, as apparent from FIG. 7, when the dimension D <b> 1 of the inclined portion 22 increases, the inclined portion 22 enters the groove 111 of the shaft 110, and the contact area of the side surface 4 with the shaft 110 decreases. In order to effectively obtain the dynamic pressure effect, the ratio of the dimension D1 of the flat portion 21 to the dimension D of the seal ring 1 is preferably limited to 16% or less.

  The seal ring 1 is made of, for example, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyimide (PI), polytetrafluoroethylene (PTFE), modified polytetrafluoroethylene, ethylene tetrafluoroethylene (ETFE), or the like. It can be formed of the following materials.

  In addition, various additives may be added to the seal ring 1 in addition to the above materials. Examples of the additive to be added to the seal ring 1 include fillers such as carbon powder and carbon fiber. By adding such a filler, a seal ring 1 with higher strength can be obtained.

  Further, examples of a method for manufacturing the seal ring 1 include an injection molding method and a compression molding method. Materials suitable for the injection molding method include, for example, resin materials such as PEEK, PPS, and PI. Examples of a material suitable for the compression molding method include a resin material such as PTFE.

  In the injection molding method or the compression molding method, the seal ring 1 having the pocket 10 and the inclined portion 22 can be directly molded. When a resin material such as PTFE is used, the seal ring 1 can be manufactured by forming the pocket 10 and the inclined portion 22 by machining after the fact.

  The dimension T (see FIG. 4) of the outer diameter and the thickness direction of the main body 1a of the seal ring 1 can be determined according to the configuration of the shaft 110 and the housing 120 to be mounted. The outer diameter of the seal ring 1 can be, for example, not less than 10 mm and not more than 200 mm. The dimension T in the thickness direction of the seal ring 1 can be, for example, 0.8 mm or more and 3.5 mm or less.

[Example]
As an embodiment of the present invention, a sample of the seal ring 1 is obtained by changing the angle α of the inclined portion 22, the ratio of the dimension T1 of the flat portion 21 to the dimension T, and the ratio of the dimension D1 of the inclined portion 22 to the dimension D. Produced. In all samples, the configuration other than the above is common, the outer diameter of the main body 1a is 50 mm, the dimension T in the thickness direction is 2.3 mm, the dimension D in the radial direction is 2.0 mm, and the number of pockets 10 is Was set to 12.

  Further, as Comparative Example 1 of the present invention, a sample of the seal ring 201 shown in FIG. 8 was produced. In the seal ring 201, the outer peripheral surface 2 is constituted only by the flat portion 21, that is, the outer peripheral surface 2 does not include the inclined portion 22. In the sample according to Comparative Example 1, the configuration other than the outer peripheral surface 2 was common to the sample according to Example.

  The samples according to Example and Comparative Example 1 were subjected to friction loss evaluation. As the friction loss evaluation, a drag torque (N · m) was measured at an oil temperature of 80 ° C. and a hydraulic pressure of 0.5 MPa. In the measurement of the drag torque, ATF was used as oil, and the rotation speed of each sample was 1500 rpm.

  9 to 11 are graphs showing measurement results of the drag torque of the sample according to the example. 9 to 11, the vertical axis indicates the drag torque. The drag torque is shown as a relative value normalized by setting the drag torque of the sample according to Comparative Example 1 to 1. That is, in the sample in which the value of the drag torque is lower than 1, the effect of the inclined portion 22 is recognized.

  In FIG. 9, the horizontal axis represents the angle α of the inclined portion 22. FIG. 9 shows a measurement result of a sample in which the dimension T1 of the flat portion 21 is unified to 0.5 mm. As shown in FIG. 9, in each of the samples in which the angle α of the inclined portion 22 was 25 ° or less, the drag torque was lower than 1, and the effect of the inclined portion 22 was recognized.

  On the other hand, in the sample in which the angle α of the inclined portion 22 was 30 ° or more, the drag torque exceeded 1, and the effect of the inclined portion 22 was not recognized. This will be described in detail with reference to FIG. 11, but it is considered that the dimension D1 becomes too large, and the inclined portion 22 enters the groove 111 of the shaft 110.

  In FIG. 10, the horizontal axis represents the ratio of the dimension T1 of the flat portion 21 to the dimension T. FIG. 10 shows a measurement result of a sample in which the angle α of the inclined portion 22 is unified to 10 °. As shown in FIG. 10, in all the samples in which the dimension T1 of the flat portion 21 with respect to the dimension T was 5% or more and 50% or less, the drag torque was lower than 1 and the effect of the inclined portion 22 was recognized.

  In FIG. 11, the horizontal axis indicates the ratio of the dimension D1 of the flat portion 21 to the dimension D. FIG. 11 includes measurement results of samples having various angles α and dimensions T1 of the inclined portions 22. As shown in FIG. 11, in all the samples in which the ratio of the dimension D1 of the flat portion 21 to the dimension D was 16% or less, the drag torque was lower than 1, and the effect of the inclined portion 22 was recognized.

  On the other hand, in the sample in which the ratio of the dimension D1 of the flat portion 21 to the dimension D exceeds 16%, the drag torque exceeded 1, and the effect of the inclined portion 22 was not recognized. In these samples, it is considered that the inclined portion 22 does not fit in the gap between the shaft 110 and the housing 120 but enters the groove 111 of the shaft 110.

  That is, in these samples, it is considered that the dynamic pressure effect could not be effectively obtained because the contact area of the side surface 4 with the shaft 110 was reduced. However, even in these samples, if the gap between the shaft 110 and the housing 120 is configured to be larger, the effect of the inclined portion 22 is considered to be obtained.

  Next, a sample of the seal ring 301 shown in FIG. 12 was produced as Comparative Example 2 of the present invention. In the seal ring 301, the outer peripheral surface 2 is constituted by the flat portion 21 and the step flat portion 322, and does not include the inclined portion 22. The step flat portion 322 is a cylindrical surface around a central axis C that forms a step G radially inward from the flat portion 21.

  In the sample according to Comparative Example 2, the configuration other than the outer peripheral surface 2 was common to the sample according to Example and Comparative Example 1. The sample according to Comparative Example 2 was evaluated for friction loss. As the friction loss evaluation, the drag torque (N · m) was measured under the same conditions as in the example and comparative example 1.

  As a result, the value of the drag torque was about 2% higher in the sample according to Comparative Example 2 than in the sample according to Comparative Example 1. That is, in the seal ring 301, reduction in friction loss due to the action of the step flat portion 322 was not recognized, and the friction loss increased rather than the seal ring 201 according to Comparative Example 1.

  This is considered to be due to the moment generated by the pressing force applied in the thickness direction to only one step G from the oil in the seal ring 301 according to Comparative Example 2. That is, in the seal ring 301, it is considered that the moment cannot maintain an appropriate posture and the friction loss increases.

  On the other hand, in the seal ring 1 according to the present embodiment, as shown in FIG. 5, the pressing force applied to the inclined portion 22 from the oil has a radial component and is directed toward the inside of the groove portion 111 of the shaft 110. ing. Therefore, the leftward component of the pressing force applied to the inclined portion 22 from the oil is offset by the rightward pressing force applied to the side surface 4 from the side wall of the groove portion 111.

  Therefore, in the seal ring 1 according to the present embodiment, unlike the seal ring 301 according to Comparative Example 2, no moment is generated by the pressing force applied to the inclined portion 22 from the oil. Therefore, by providing the inclined portion 22, the seal ring 1 does not easily lose its balance during driving, and can maintain an appropriate posture.

[Other Embodiments]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

  For example, the pocket 10 is not limited to the above configuration. The pockets 10 may be provided at intervals on the side surface 4, the outer peripheral surface 2 side may be closed, and the inner peripheral surface 3 side may be open. Further, the pockets 10 do not need to be arranged in the circumferential direction on both side surfaces 4, and may be shifted in the circumferential direction.

  The main body 1a of the seal ring 1 preferably has a shape symmetrical in the thickness direction in that it is not necessary to pay attention to the mounting direction, but may have a shape asymmetrical in the thickness direction as necessary. . For example, as shown in FIGS. 13A and 13B, the outer peripheral surface 2 of the main body 1a of the seal ring 1 may have an asymmetric shape in the thickness direction.

  That is, as shown in FIG. 13A, the flat portion 21 may be shifted from the center in the thickness direction, and the shapes of the two inclined portions 22 disposed on both sides thereof may be different. This allows the two inclined portions 22 to have different characteristics from each other, so that a common seal ring 1 can be used in two different designs.

  Further, as shown in FIG. 13B, the flat portion 21 may be disposed at one end in the thickness direction, and only one inclined portion 22 may be provided. With this configuration, it is possible to increase the size of the inclined portion 22 while sufficiently securing the size T1 of the flat portion 21. Thereby, the friction loss between the outer peripheral surface 2 and the housing 120 can be more effectively reduced.

DESCRIPTION OF SYMBOLS 1 ... Seal ring 1a ... Body part 1b ... Aperture part 2 ... Outer peripheral surface 3 ... Inner peripheral surface 4 ... Side surface 10 ... Pocket 11 ... Bottom part 12 ... Slope part 13 ... Partition part 14 ... Column part 21 ... Flat part 22 ... Sloping part 110: shaft 111: groove 120: housing

Claims (8)

Facing outward in the radial direction, a flat portion, and an outer peripheral surface including an inclined portion inclined inward in the radial direction from the flat portion toward the outside in the thickness direction,
An inner peripheral surface facing inward in the radial direction,
A side surface facing outward in the thickness direction,
A plurality of pockets provided at intervals on the side surface, the outer peripheral surface side is closed, and the inner peripheral surface side is open,
A seal ring. The seal ring according to claim 1,
A seal ring, wherein the flat portion is located at a central portion in the thickness direction. The seal ring according to claim 1 or 2,
Further comprising an abutting portion and a main body extending annularly between the abutting portions,
The seal ring, wherein the inclined portion is not formed at the abutment portion. The seal ring according to claim 3, wherein
The seal ring, wherein the inclined portion is formed continuously over the entire circumference of the main body. The seal ring according to any one of claims 1 to 3, wherein
A seal ring, wherein the inclined portion includes a plurality of inclined portions formed at intervals from each other. The seal ring according to any one of claims 1 to 5,
An angle between the cylindrical surface obtained by extending the flat portion in the thickness direction and the inclined portion is 25 ° or less. The seal ring according to any one of claims 1 to 6,
A seal ring, wherein a dimension of the flat portion in the thickness direction is 3% or more and 80% or less of a dimension of the outer peripheral surface in the thickness direction. The seal ring according to any one of claims 1 to 7,
The seal ring has a radial dimension of the inclined portion that is 16% or less of a distance between the flat portion and the inner peripheral surface.

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