Sliding parts

Abstract

To provide sliding parts that can slide against each other stably and smoothly. [Solution] A sliding component is provided which a pair of sliding surfaces 11 and 21 are arranged at a point where they rotate relative to each other, and which separates an outer space S1 and an inner space S2, wherein one of the sliding surfaces 11 has an annular groove 12 and a wall portion 15 that generates positive pressure provided within the annular groove 12.

Description

Technical Field

[0001] The present invention relates to sliding parts that rotate relative to each other, and is used, for example, as a sliding part for a shaft sealing device that seals the rotating shaft of a rotating machine in the field of automobiles, general industrial machinery, or other sealing fields, or as a sliding part used for a bearing of a machine in the field of automobiles, general industrial machinery, or other bearing fields.

Background Art

[0002] As a sliding part for preventing leakage of fluid around the rotating shaft in a rotating machine, for example, a mechanical seal composed of a pair of annular sliding rings that rotate relative to each other and whose sliding surfaces slide against each other is known. In such a mechanical seal, in recent years, reduction of energy lost due to sliding has been desired for environmental protection and the like, and some sliding surfaces of the sliding rings are provided with dimples.

[0003] For example, a plurality of dimples are formed on the sliding surface of the stationary sealing ring of the mechanical seal shown in Patent Document 1. The dimples have a crank shape, and include an upstream cavitation formation region that extends in the circumferential direction on the inner space side where low-pressure fluid exists, a downstream positive pressure generation region that extends in the circumferential direction on the outer space side where high-pressure fluid exists, and a region that extends in the radial direction and communicates with the downstream end of the cavitation formation region and the upstream end of the positive pressure generation region. Also, the dimples are not in communication with the outer space or the inner space.

[0004] The mechanical seal shown in Patent Document 1 can guide the sealed fluid that has moved to the inner space side and flowed into the cavitation formation region during the relative rotation of the rotating sealing ring to the closed end on the downstream side of the positive pressure generation region, and supply the sealed fluid from this closed end and its vicinity to between the sliding surfaces. Thereby, it is possible to reduce the sealed fluid leaking into the inner space.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the mechanical seal described in Patent Document 1, the positive pressure generated at and near the closed end of the positive pressure generation region slightly separates the sliding surfaces, thereby reducing the frictional force generated during relative rotation between the sliding surfaces. On the other hand, since some of the sealed fluid is returned to the outside space from the closed end, there was a risk that the amount of sealed fluid in the dimple would be insufficient, hindering the generation of positive pressure.

[0007] This invention was made in view of these problems, and aims to provide a sliding component capable of stably generating positive pressure. [Means for solving the problem]

[0008] To solve the aforementioned problems, the sliding component of the present invention is A sliding component in which a pair of sliding surfaces are positioned at a location where they rotate relative to each other, and which separates an outer space from an inner space, At least one of the sliding surfaces has an annular groove and a wall portion provided within the annular groove that generates positive pressure. According to this, the sealed fluid in the annular groove is stably supplied to the wall, allowing for stable positive pressure to be generated at the wall. This enables stable and smooth relative sliding.

[0009] The wall portion has a side wall extending in the circumferential direction on at least one of the outer diameter side and the inner diameter side, The annular groove may have a base portion located upstream of the wall portion in relative rotation, and a protrusion portion that is narrower than the base portion and faces the side wall and is connected to the base portion. According to this, the sealed fluid within the protrusion is guided by the side wall, making it easier to efficiently generate positive pressure.

[0010] The cross-sectional area of ​​the flow path on the downstream side of the relative rotation may be narrower than that on the upstream side of the relative rotation. According to this, it becomes easier to guide the fluid to be sealed into the protruding part.

[0011] The wall portions may be arranged in multiple locations in the circumferential direction, and the annular groove may have a connecting portion that connects adjacent base portions in the circumferential direction. According to this, it becomes possible to guide the sealed fluid from the base on the upstream side of the relative rotation to the base on the downstream side of the relative rotation through the connecting section.

[0012] The communication portion may be provided on the outer space side and the inner space side, respectively, of the wall portion. According to this design, the communication portion on the outer space side and the communication portion on the inner space side can be made to overlap radially with the wall portion. This prevents the sealed fluid from flowing out from the wall portion into the outer or inner space, making it easier to retain the sealed fluid between the sliding surfaces.

[0013] The radial length of the wall portion may be longer than the sum of the radial length of the communication portion on the inner space side and the radial length of the communication portion on the outer space side. According to this, positive pressure is more likely to occur within a sufficient range.

[0014] The annular groove may have a depth at least on the downstream side of the convex portion that is less than the depth of the base portion. According to this, it becomes easier to guide the fluid to be sealed into the protruding part.

[0015] A guide groove may be provided within the annular groove, extending inclined from the upstream side of relative rotation toward the radial center of the protrusion and toward the downstream side of relative rotation. According to this, it is efficient in generating positive pressure.

[0016] The wall portion may extend toward the other sliding surface so as to be in sliding contact with the other sliding surface. According to this, the wall section forms part of the land, and is efficient at generating positive pressure. [Brief explanation of the drawing]

[0017] [Figure 1] It is a longitudinal sectional view showing an example of a mechanical seal in Example 1 according to the present invention. [Figure 2] It is a view of the sliding surface of the stationary seal ring in Example 1 as seen from the axial direction. [Figure 3] It is an enlarged view of the main part of FIG. 2. [Figure 4] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 2 according to the present invention. [Figure 5] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 3 according to the present invention. [Figure 6] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 4 according to the present invention. [Figure 7] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 5 according to the present invention. [Figure 8] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 6 according to the present invention. [Figure 9] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Modified Example 6-1 of Example 6. [Figure 10] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 7 according to the present invention. [Figure 11] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Modified Example 7-1 of Example 7. [Figure 12] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 8 according to the present invention. [Figure 13] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 9 according to the present invention. [Figure 14] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 10 according to the present invention. [Figure 15] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 11 according to the present invention. [Figure 16] It is an enlarged view of the main part of the sliding surface of the stationary seal ring in Example 12 according to the present invention. [Figure 17]This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in Embodiment 13 of the present invention. [Figure 18] This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in modified example 13-1 of Example 13. [Figure 19] This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in Embodiment 14 of the present invention. [Modes for carrying out the invention]

[0018] Embodiments for implementing the sliding component according to the present invention will be described below based on examples. [Examples]

[0019] The sliding component according to Example 1 will be described with reference to Figures 1 to 3. In this example, a mechanical seal will be used as an example of a sliding component. For the sake of explanation, dots may be added to the grooves formed on the sliding surface in the drawings; the denser the dots, the deeper the groove, and the sparser the dots, the shallower the groove.

[0020] The mechanical seal shown in Figure 1 separates the outer space S1, where the sealed fluid F (such as oil) is present, from the inner space S2, where the atmosphere A is present. In other words, the mechanical seal is an inside type that seals against the leakage of the sealed fluid F from the outer space S1 to the inner space S2. Furthermore, this embodiment illustrates a configuration in which the atmosphere A is at a lower pressure than the sealed fluid F.

[0021] Furthermore, the sealed fluid F, such as oil, may be present in the inner space S2, and the atmosphere A may be present in the outer space S1, with the sealed fluid F attempting to leak from the inner space S2 towards the outer space S1 being sealed. The atmosphere A may be at a higher pressure than or equal to the sealed fluid F. The types of fluids present in the outer space S1 and inner space S2 may be changed as appropriate. Moreover, the fluids present in the outer space S1 and inner space S2 may be the same fluid.

[0022] The mechanical seal comprises a stationary sealing ring 10 and a rotating sealing ring 20. The stationary sealing ring 10 is fixed to a seal cover 5 which is fixed to the housing 4 of the equipment to be mounted, in a non-rotatable and axially movable state. The rotating sealing ring 20 is attached to a sleeve 2 which is fixed to a rotating shaft 1 and is rotatable together with the rotating shaft 1.

[0023] The stationary sealing ring 10 is biased axially by the elastic member 7. The sliding surface 11 of the stationary sealing ring 10, which serves as one sliding surface, and the sliding surface 21 of the rotating sealing ring 20, which serves as the other sliding surface, are in close contact with each other. The sliding surface 21 of the rotating sealing ring 20 is a flat surface and does not have any grooves or other recesses.

[0024] The stationary sealing ring 10 and the rotating sealing ring 20 are typically formed from two SiC (hard material) components or a combination of SiC (hard material) and carbon (soft material). However, the sliding material is not limited to these; any sliding material used for mechanical seals is applicable. SiC can be sintered using boron, aluminum, or carbon as sintering aids, or from materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, or SiC-TiN. Carbon can be a mixture of carbonaceous and graphite, as well as resin-molded carbon and sintered carbon. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), and composite materials are also applicable.

[0025] As shown in Figure 2, the rotating sealing ring 20 slides relative to the stationary sealing ring 10 in a counterclockwise direction, as indicated by the solid arrow. In this embodiment, with this relative rotation direction as the reference, the clockwise side from the target position is described as the upstream side in the relative rotation direction, and the counterclockwise side from the target position is described as the downstream side in the relative rotation direction.

[0026] The sliding surface 11 of the stationary sealing ring 10 has an annular groove 12 that extends continuously along the circumferential direction. The annular groove 12 is a groove of approximately constant depth and is defined by an annular outer diameter land 13 and an inner diameter land 14 that extend continuously along the circumferential direction. In other words, the annular groove 12 is a dimple that does not communicate with the outer space S1 and the inner space S2.

[0027] Furthermore, six central lands 15, which serve as walls, are equally arranged within the annular groove 12. The lands 13, 14, and 15 form flat surfaces on the sliding surface 11 and are capable of sliding contact with the sliding surface 21 of the rotating sealing ring 20. The number and arrangement of the central lands 15 may be changed as appropriate.

[0028] In the following explanation, the upstream side in the relative rotation direction may simply be referred to as the "upstream side," and the downstream side in the relative rotation direction may simply be referred to as the "downstream side."

[0029] The central land 15 is formed in a U-shape when viewed from the axial direction, and has an outer diameter side circumferential wall 15a as a side wall extending along the circumferential direction, an inner diameter side circumferential wall 15b as a side wall extending along the circumferential direction at a position spaced further inward than the outer diameter side circumferential wall 15a, and a radial wall 15c that extends along the radial direction and is continuous with the downstream ends of the circumferential walls 15a and 15b, respectively.

[0030] The annular groove 12 has six protrusions 16, six bases 17, six outer diameter-side connecting portions 18 as connecting portions on the outer space side, and six inner diameter-side connecting portions 19 as connecting portions on the inner diameter side. The number and arrangement of the protrusions 16, bases 17, and connecting portions 18, 19 may be changed as appropriate.

[0031] The protrusion 16 is a portion defined in the central land 15 and extends along the circumferential direction. In other words, the circumferential walls 15a, 15b and the radial wall 15c face the protrusion 16.

[0032] The protrusion 16 is separated from the outer diameter side communication section 18 by the outer diameter side circumferential wall 15a and radial wall 15c in the central land 15, separated from the inner diameter side communication section 19 by the inner diameter side circumferential wall 15b and radial wall 15c, and separated from the adjacent downstream base section 17 by the radial wall 15c.

[0033] The upstream end of the protrusion 16 is open toward the upstream side and communicates with the radial center of the adjacent upstream base 17. The downstream end of the protrusion 16 is a closed end 16a.

[0034] In this embodiment, the protrusion 16 has a rectangular cross-sectional shape, but it may also be semicircular or triangular, and may be modified as appropriate. The same applies to the base 17, the outer diameter side communication portion 18, and the inner diameter side communication portion 19.

[0035] The base portion 17 is the part between the outer diameter land 13 and the inner diameter land 14 in the radial direction, and extends along the circumferential direction. The upstream end of the base portion 17 faces the radial wall 15c of the adjacent upstream central land 15, and the downstream end faces the circumferential walls 15a and 15b of the adjacent relative rotation downstream central land 15. The radial center of the base portion 17 substantially coincides with the radial center of the convex portion 16.

[0036] The protrusions 16 overlap circumferentially with the radial centers of adjacent base portions 17 in the circumferential direction. In this invention, circumferential overlap means that the protrusions are located at the same radial position but at different circumferential positions.

[0037] The outer diameter side connecting portion 18 is the portion between the central land 15 and the outer diameter side land 13 in the radial direction, and extends along the circumferential direction. The outer diameter side connecting portion 18 communicates with the outer diameter side of each adjacent base portion 17 in the circumferential direction. The inner diameter side surface 13a of the outer diameter side land 13 is the surface that separates the outer diameter side connecting portion 18 from the outer diameter side of the base portion 17 (see Figure 3). The side surface 13a extends along the circumferential direction and forms an annular shape.

[0038] The inner diameter side communication portion 19 is the portion between the central land 15 and the inner diameter side land 14 in the radial direction, and extends along the circumferential direction. The inner diameter side communication portion 19 communicates with the inner diameter side of each adjacent base portion 17 in the circumferential direction. The outer diameter side surface 14a of the inner diameter side land 14 is the surface that demarcates the inner diameter side communication portion 19 from the inner diameter side of the base portion 17 (see Figure 3). The side surface 14a extends along the circumferential direction and forms an annular shape.

[0039] The protrusions 16 overlap radially from the upstream end to the circumferential center of the connecting portions 18 and 19. In this invention, radial overlap means that the protrusions are located at the same circumferential position but at different radial positions.

[0040] Next, the sealing between the outer space S1 and the inner space S2 by the stationary sealing ring 10 and the rotating sealing ring 20 will be explained using Figure 3. Note that the fluid flow in Figure 3 is shown in a schematic manner.

[0041] When the rotating sealing ring 20 is not rotating and the mechanical seal is inactive, the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 are in contact. This prevents the sealed fluid F from flowing out into the internal space S2. Furthermore, the sealing efficiency of the mechanical seal is enhanced because the outer and inner diameter ends of the sliding surface 11 are annular lands 13 and 14, respectively.

[0042] When the rotating sealing ring 20 is rotating relative to the other ring, as shown by the black arrow in Figure 3, the fluid F to be sealed in the annular groove 12 attempts to move in the direction of rotation of the rotating sealing ring 20 due to shear with the sliding surface 21.

[0043] The sealed fluid F within the communicating portions 18 and 19 in the annular groove 12 is guided along the communicating portions 18 and 19 toward the base 17.

[0044] The sealed fluid F within the base 17 is guided along the base 17 towards the convex portion 16 and the communication portions 18, 19, and is guided to the convex portion 16 and the communication portions 18, 19 by the circumferential walls 15a, 15b of the central land 15. This will be described in detail hereinafter.

[0045] The flow path cross-sectional area C of the base 17 is the product of the width W of the base 17, that is, the radial length, and the depth of the base 17. The flow path cross-sectional area C1 of the convex portion 16 is the product of the width W1 of the convex portion 16 and the depth of the convex portion 16. The flow path cross-sectional area C2 of the outer diameter side communication portion 18 is the product of the width W2 of the communication portion 18 and the depth of the communication portion 18. The flow path cross-sectional area C2 of the inner diameter side communication portion 19 is the product of the width W2 of the communication portion 19 and the depth of the communication portion 19. The width W2 of the outer diameter side communication portion 18 and the width W2 of the inner diameter side communication portion 19 are substantially the same.

[0046] The width W of the base 17 where the central land 15 is not formed is longer than the sum (W1 + W2×2) of the width W1 of the convex portion 16 partitioned by the central land 15, the width W2 of the communication portion 18, and the width W2 of the communication portion 19 (W > W1 + W2×2). Also, as described above, the depths of the convex portion 16, the base 17, and the communication portions 18, 19 are substantially the same and the depth is constant.

[0047] As a result, the sum (C1 + C2×2) of the flow path cross-sectional area C1 of the convex portion 16, the flow path cross-sectional area C2 of the communication portion 18, and the flow path cross-sectional area C2 of the communication portion 19 is narrower than the flow path cross-sectional area C of the base 17 by the central land 15 (C1 + C2×2 < C). The sealed fluid F within the base 17 flows into the convex portion 16 and the communication portions 18, 19 where the flow path cross-sectional area is narrower than that of the base 17.

[0048] Also, the width W1 of the convex portion 16 is longer than the width W2 of each of the communication portions 18, 19 (W > W1 > W2). As a result, the flow path cross-sectional area C1 of the convex portion 16 is wider than the flow path cross-sectional area C2 of each of the communication portions 18, 19 (C1 > C2). The amount of the sealed fluid F flowing from the base 17 into the convex portion 16 is more likely to be larger than the amount of the sealed fluid F flowing into one of the communication portions 18, 19.

[0049] Furthermore, the width W1 of the protrusion 16 is longer than the sum of the widths W2 of the connecting sections 18 and 19 (W2 × 2) (W1 > W2 × 2). As a result, the flow path cross-sectional area C1 of the protrusion 16 is wider than the sum of the flow path cross-sectional areas C2 of the connecting sections 18 and 19 (C2 × 2) (C1 > C2 × 2). The amount of sealed fluid F flowing from the base 17 into the protrusion 16 is likely to be greater than the amount of sealed fluid F flowing into the connecting sections 18 and 19.

[0050] The sealed fluid F within the protrusion 16 is guided along the protrusion 16, more specifically by the inner surface 15a1 of the circumferential wall 15a and the outer surface 15b1 of the circumferential wall 15b in the central land 15, toward the closed end 16a, and flows out into the central land 15 from the closed end 16a and its vicinity, which is composed of the upstream surface 15c1 of the radial wall 15c. In other words, it is supplied between the sliding surfaces 11 and 21.

[0051] Positive pressure is generated at the closed end 16a and its vicinity. In other words, positive pressure can be generated at the location of the central land 15. As described above, since much of the sealed fluid F in the base 17 flows into the convex portion 16, which has a narrower flow path cross-sectional area than the base 17, it is easier to increase the positive pressure generated at the closed end 16a and its vicinity.

[0052] In the mechanical seal, the positive pressure generated at and near each closed end 16a causes the sliding surfaces 11 and 21 to separate slightly. The fluid film formed by the sealed fluid F that flows between these sliding surfaces 11 and 21 reduces the frictional force caused by the relative sliding of the sliding surfaces 11 and 21.

[0053] Furthermore, since each closed end 16a is located at the radial center of the sliding surface 11 in the stationary sealing ring 10, the sliding surfaces 11 and 21 can be spaced apart in a balanced manner.

[0054] On the other hand, some of the sealed fluid F within the base 17 flows directly out to the circumferential walls 15a and 15b of the central land 15. This sealed fluid F is in small quantities and does not tend to concentrate like the convex portion 16. As a result, almost no positive pressure is generated near the boundary between the base 17 and the central land 15.

[0055] The fluid to be sealed F supplied between the sliding surfaces 11 and 21 from the closed end 16a of the protrusion 16 and its vicinity attempts to move in the rotational direction of the rotating sealing ring 20 due to shear with the sliding surface 21. As a result, most of the fluid to be sealed F moves almost along the circumferential direction and flows into the adjacent base portion 17 on the downstream side.

[0056] Furthermore, some of the sealed fluid F supplied between the sliding surfaces 11 and 21 from the closed end 16a and its vicinity may move toward the outer space S1 or the inner space S2. Hereafter, this may simply be described as "moving toward the outer space S1 from the protrusion 16."

[0057] The sealed fluid F moving from the protrusion 16 towards the outer space S1 flows into the outer diameter side communicating portion 18 which overlaps radially, thereby hindering its movement toward the outer space S1 and making it more likely to remain between the sliding surfaces 11 and 21.

[0058] The sealed fluid F moving from the protrusion 16 towards the inner space S2 flows into the inner diameter side communicating portion 19 which overlaps radially, thereby hindering its movement toward the inner space S2 and making it more likely to remain between the sliding surfaces 11 and 21.

[0059] These also apply to the sealed fluid F that flows directly from the base 17 to the central land 15.

[0060] Furthermore, the sealed fluid F that flows from the central land 15 into the connecting sections 18 and 19 is guided to the base 17 by the shear force of the sliding surface 21, as described above. The same applies to the sealed fluid F that flows from the base 17 into the connecting sections 18 and 19. In other words, the annular groove 12 facilitates the circulation of the sealed fluid F within the annular groove 12 while retaining it within the annular groove 12, or in other words, between the sliding surfaces 11 and 21.

[0061] As described above, in this embodiment, the mechanical seal has a sliding surface 11 in the stationary sealing ring 10, and a central land 15 that generates positive pressure is located within the annular groove 12. With this configuration, the fluid F to be sealed in the annular groove 12 is stably supplied to the central land 15, so that positive pressure can be stably generated at the position of the central land 15. This makes it possible to slide relative to each other stably and smoothly.

[0062] Furthermore, multiple central lands 15 are arranged circumferentially within the annular groove 12. In other words, the sliding surface 11 is provided with an annular groove 12 in which multiple central lands 15 that generate positive pressure are arranged circumferentially. With this configuration, positive pressure is stably generated at the position of each central land 15, making it easier to keep the sliding surfaces 11 and 21 approximately parallel to each other. In other words, uneven contact can be prevented, making it possible to slide relative to each other more stably and smoothly.

[0063] Furthermore, since the annular groove 12 is an endless annular dimple that does not communicate with the outer space S1 or the inner space S2, the value of the positive pressure generated at each central land 15, as well as the amount or area in which the positive pressure is generated, are almost equal. As a result, the parallelism between the sliding surfaces 11 and 21 is easily maintained, enabling smooth sliding. In contrast, for example, in a C-shaped end groove extending along the circumferential direction, the positive pressure generated at each central land 15 varies in the circumferential direction. Also, in an end groove for generating negative pressure that communicates with the outer space S1 or the inner space S2, the positive pressure and relative negative pressure generated at each central land 15 vary in the circumferential direction, causing the sliding surfaces 11 and 21 to tilt relative to each other, making it easy for so-called uneven contact to occur.

[0064] Furthermore, the convex portion 16 facilitates the efficient generation of positive pressure because the incoming sealed fluid F is guided by the circumferential walls 15a and 15b in the central land 15.

[0065] Furthermore, the annular groove 12 allows the sealed fluid F to be guided from the upstream base 17 to the downstream base 17 through the connecting portions 18 and 19.

[0066] Furthermore, the annular groove 12 has an outer diameter side communicating portion 18 and an inner diameter side communicating portion 19 that overlap radially with the central land 15. This prevents the sealed fluid F from flowing out from the central land 15 into the outer space S1 or inner space S2, making it easier to retain the sealed fluid F between the sliding surfaces 11 and 21. This allows for high load capacity and high film thickness.

[0067] Furthermore, since the annular groove 12 generates almost no relative negative pressure, the atmosphere A in the internal space S2 is less likely to flow into the annular groove 12 compared to the sealed fluid F. As a result, even when the rotation of the rotating sealing ring 20 stops, a large amount of the sealed fluid F can be retained in the annular groove 12.

[0068] From this perspective, even if the pressure of the fluid in the outer space S1 and the fluid in the inner space S2 are the same or approximately the same, a positive pressure is generated at the position of the central land 15 in the annular groove 12, and the fluid can be held between the sliding surfaces 11 and 21 by the connecting parts 18 and 19, so that the sliding surfaces 11 and 21 can slide relative to each other stably and smoothly.

[0069] Furthermore, as shown in Figure 3, the width W3 of the central land 15 is longer than the sum of the widths W2 of the connecting sections 18 and 19 (W2 × 2) (W3 > W2 × 2). This makes it easier for positive pressure to be generated over a sufficient range.

[0070] Furthermore, the central land 15 extends toward the sliding surface 21 so as to be able to slide against the sliding surface 21 of the rotating sealing ring 20, and its top surface is flush with the outer diameter land 13 and the inner diameter land 14. Therefore, it is easier to narrow the axial gap with the sliding surface 21 than with the wall portion which cannot slide against the sliding surface 21. As a result, the central land 15 is more efficient at concentrating the sealed fluid F at the closed end 16a of the protrusion 16 and its vicinity than with the wall portion which cannot slide against the sliding surface, thus generating positive pressure more efficiently.

[0071] Although the wall portion may not be able to slide against the sliding surface 21, it is preferable that it be able to slide against the sliding surface 21 from the viewpoint of efficient generation of positive pressure.

[0072] Although it was explained that the depth of the base 17 is approximately the same as the depth of the protrusion 16, this may be changed as appropriate. For example, by making the depth of the base greater than the depth of the protrusion 16, the volume of the base can be increased, making it possible to store more fluid.

[0073] Furthermore, although it was explained that the depth of the connecting sections 18 and 19 is approximately the same as the depth of the protrusion 16, this may be changed as appropriate. For example, by making the depth of the connecting sections greater than the depth of the protrusion 16, the volume of the connecting sections can be increased, making it possible to store more fluid. On the other hand, from the viewpoint that the flow path cross-sectional area widens as the depth increases, and the amount of fluid flowing in increases, it is preferable to make the depth approximately the same as that of the protrusion 16.

[0074] Furthermore, by making the depth of the connecting portion shallower than the depth of the protrusion 16, the cross-sectional area of ​​the flow path can be narrowed, making it easier for the fluid to be guided into the protrusion 16. On the other hand, from the viewpoint that the shallower it is, the smaller the volume and the less fluid can be stored, it is preferable to make the depth about the same as the depth of the protrusion 16. [Examples]

[0075] Next, the sliding parts according to Embodiment 2 will be described with reference to Figure 4. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0076] As shown in Figure 4, the sliding surface 211 of the stationary sealing ring 210 in Embodiment 2 has protruding portions 213b and 214b formed on the lands 213 and 214, which extend toward the radial center.

[0077] The annular groove 212 has its width narrowed in the circumferential central portion 217a of the base 217 by the protruding portions 213b and 214b. In the base 217, the upstream portion 217b and the downstream portion 217c, other than the circumferential central portion 217a, are approximately the same width as the base 17 of Embodiment 1.

[0078] With this configuration, the sealed fluid F that flows from the connecting sections 18 and 19 into the upstream section 217b is guided by the protruding sections 213b and 214b to the circumferential central section 217a, that is, toward the radial center of the base section 217.

[0079] Furthermore, the sealed fluid F that flows from the circumferential central portion 217a to the downstream portion 217c is subjected to the shear force of the sliding surface 21, and much of it flows into the downstream protrusion 16 which overlaps with the circumferential central portion 217a. As a result, the amount of sealed fluid F that flows into the protrusion 16 tends to be larger than in Embodiment 1, making it easier to generate a high positive pressure at the location of the central land 15.

[0080] Furthermore, some of the sealed fluid F that flows into the upstream portion 217b from the connecting portions 18 and 19 flows out to the protruding portions 213b and 214b without being guided to the circumferential central portion 217a. Most of this sealed fluid F is subjected to the shear force of the sliding surface 21 and flows into the downstream portion 217c.

[0081] On the other hand, from the viewpoint of more stably retaining the sealed fluid F between the sliding surfaces, it is preferable that the side surfaces defining the annular grooves extend along the circumferential direction, as in the side surfaces 13a and 14a of the lands 13 and 14 in Embodiment 1. [Examples]

[0082] Next, the sliding parts according to Embodiment 3 will be described with reference to Figure 5. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0083] As shown in Figure 5, the stationary sealing ring 310 in Embodiment 3 is designed for both counterclockwise and clockwise rotation of the rotating sealing ring 20, as indicated by the solid arrows.

[0084] In this embodiment, forward rotation means that the rotating sealing ring 20 is rotating counterclockwise, and reverse rotation means that the rotating sealing ring 20 is rotating clockwise. Unless otherwise specified, the description will assume that the rotating sealing ring 20 rotates counterclockwise, as in Embodiment 1. In addition, the upstream side in the reverse rotation direction may be simply referred to as the "reverse upstream side," and the downstream side in the reverse rotation direction may be simply referred to as the "reverse downstream side."

[0085] In the sliding surface 311 of the stationary sealing ring 310, a central land 315 is formed within the annular groove 312, instead of the central land 15 in the first embodiment.

[0086] The central land 315 is formed in an H shape when viewed from the axial direction, and has walls 15a, 15b, and 15c, an outer diameter side circumferential wall 315a extending downstream from the outer diameter side of the radial wall 15c, and an inner diameter side circumferential wall 315b extending downstream from the inner diameter side of the radial wall 15c.

[0087] The annular groove 312 is defined by walls 315a, 15c, and 315b and has an inverted protrusion 316 extending along the circumferential direction. The upstream end of the inverted protrusion 316 is a closed end 316a. The downstream end of the inverted protrusion 316 communicates with the radial center on the upstream side of the adjacent downstream base 17.

[0088] With this configuration, when the rotating sealing ring 20 rotates in the forward direction, positive pressure is generated at the closed end 16a of the protrusion 16 and in its vicinity.

[0089] The sealed fluid F within the inverted protrusion 316 is guided toward the adjacent downstream base 17 by the circumferential walls 315a and 315b in the central land 315. On the upstream side of the inverted protrusion 316, i.e., the closed end 316a side, a relative negative pressure is generated. That is, the force sucking in the sealed fluid F becomes stronger. Hereafter, the relative negative pressure will be simply referred to as "negative pressure".

[0090] Furthermore, the sealed fluid F supplied from the protrusion 16 between the sliding surfaces 311 and 21 flows into the adjacent base 17 and inverted protrusion 316 downstream, as well as the radially overlapping connecting portions 18 and 19. In other words, the annular groove 312 facilitates the retention of the sealed fluid F between the sliding surfaces 311 and 21.

[0091] When the rotating sealing ring 20 rotates in the reverse direction, the sealed fluid F within the inverted protrusion 316 is guided along the circumferential walls 315a and 315b toward the closed end 316a, and supplied between the sliding surfaces 311 and 21 from the closed end 316a and its vicinity. Positive pressure is also generated at the closed end 316a and its vicinity.

[0092] Even during reverse rotation, the sealed fluid F in the annular groove 312 is stably supplied to each central land 315, just as during forward rotation, so that positive pressure can be stably generated at the position of each inverted protrusion 316.

[0093] The sealed fluid F within the protrusion 16 is guided along the circumferential walls 15a and 15b toward the adjacent reverse-downstream base 17. Negative pressure is generated on the reverse-upstream side of the protrusion 16, i.e., the closed end 16a side.

[0094] Furthermore, the sealed fluid F supplied from the inverted protrusion 316 between the sliding surfaces 311 and 21 flows into the adjacent base 17 and protrusion 16 on the downstream side, and into the radially overlapping connecting portions 18 and 19. In other words, the annular groove 312 makes it easier to retain the sealed fluid F between the sliding surfaces 311 and 21. [Examples]

[0095] Next, the sliding parts according to Embodiment 4 will be described with reference to Figure 6. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0096] As shown in Figure 6, the stationary sealing ring 410 in Example 4 is designed for both rotation and rotation, similar to Example 3.

[0097] In the sliding surface 411 of the stationary sealing ring 410, a central land 315 is formed within the annular groove 412, instead of the central land 15 in Embodiment 1. In addition, protruding portions 213b and 214b are formed on the lands 213 and 214, extending toward the radial center.

[0098] With this configuration, when the rotating sealing ring 20 rotates in the forward direction, the protruding portions 213b and 214b make it easier to guide the fluid to be sealed into the protrusion 16, thus making it easier to generate a high positive pressure at the position of the central land 315.

[0099] Furthermore, when the rotating sealing ring 20 rotates in the reverse direction, the protruding portions 213b and 214b make it easier to guide the sealed fluid F into the inverted protrusion 316, thus making it easier to generate a high positive pressure at the position of the central land 315. [Examples]

[0100] Next, the sliding parts according to Embodiment 5 will be described with reference to Figure 7. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0101] As shown in Figure 7, the stationary sealing ring 510 in Example 5 is designed for both rotation and rotation, similar to Example 3.

[0102] In the stationary sealing ring 510, a central land 515 is formed within the annular groove 512 on the sliding surface 511, instead of the central land 15 in the first embodiment.

[0103] The central land 515 is formed in an M shape when viewed from the axial direction, and has an outer diameter side circumferential wall 515a as a side wall extending circumferentially on the upstream and outer diameter side, an inner diameter side circumferential wall 515b as a side wall extending circumferentially on the upstream and inner diameter side, a central wall 515c as a side wall continuous with the downstream ends of the circumferential walls 515a and 515b, an outer diameter side narrow circumferential wall 515d as a side wall extending circumferentially on the outer diameter side of the central wall 515c and continuous with the outer diameter side portion of the downstream end of the outer diameter side circumferential wall 515a, and an inner diameter side narrow circumferential wall 515e as a side wall extending circumferentially on the inner diameter side of the central wall 515c and continuous with the inner diameter side portion of the downstream end of the inner diameter side circumferential wall 515b.

[0104] The annular groove 512 has a protrusion 516F defined by walls 515a, 515c, and 515b, an inverted protrusion 516R on the outer diameter side defined by walls 515d, 515a, and 515c, and an inverted protrusion 516R on the inner diameter side defined by walls 515e, 515b, and 515c.

[0105] The inverted protrusion 516R on the outer diameter side is located further outward than the protrusion 516F. The inverted protrusion 516R on the inner diameter side is located further inward than the protrusion 516F. The downstream portion of the protrusion 516F and the upstream portions of the two inverted protrusions 516R overlap radially.

[0106] With this configuration, when the rotating sealing ring 20 rotates in the forward direction, positive pressure is generated at the closed end 516Fa of the protrusion 516F and in its vicinity. In addition, negative pressure is generated on the closed end 516Ra side of the two inverted protrusions 516R.

[0107] Furthermore, the sealed fluid F supplied from the protrusion 516F between the sliding surfaces 511 and 21 flows into the adjacent base 17 downstream, the radially overlapping connecting portions 18 and 19, and the two inverted protrusions 516R.

[0108] In other words, in the annular groove 512, the sealed fluid F moving from the protrusion 516F to the outer space S1 side or the inner space S2 side is obstructed not only by the communicating portions 18 and 19 but also by the two inverted protrusions 516R, making it easier to retain the sealed fluid F between the sliding surfaces 511 and 21 than in the previous embodiment 1.

[0109] Furthermore, when the rotating sealing ring 20 rotates in the reverse direction, positive pressure can be generated at the closed ends 516Ra and their vicinity of each of the two radially separated inverted protrusions 516R. This allows the sliding surfaces 511 and 21 to be spaced apart in a balanced manner. In addition, negative pressure is generated on the closed end 516Fa side of the protrusion 516F.

[0110] The width W51 of the convex portion 516F is longer than the width W52 of the inverted convex portion 516R (W51 > W52). Also, the depth of the convex portion 516F and the depth of the inverted convex portion 516R are approximately the same. The flow channel cross-sectional area C51 of the convex portion 516F, which is the product of the width W51 and the depth, is wider than the flow channel cross-sectional area C52 of the inverted convex portion 516R, which is the product of the width W52 and the depth (C51 > C52).

[0111] As a result, in the convex portion 516F, positive pressure is generated even if the rotational speed during forward rotation exceeds the rotational speed during reverse rotation at which positive pressure can be generated in the inverted convex portion 516R. In other words, the range of rotational speeds at which positive pressure can be generated differs between forward and reverse rotation. [Examples]

[0112] Next, the sliding parts according to Embodiment 6 will be described with reference to Figure 8. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0113] As shown in Figure 8, the stationary sealing ring 610 in Example 6 is designed for unidirectional rotation, similar to Example 1.

[0114] In the annular groove 612, the depth of the downstream portion 616b, which includes the closed end 616a at the protrusion 616, is shallower than the depth of the adjacent upstream portion 616c on the upstream side. The depth of the upstream portion 616c is approximately the same as the depth of the base portion 17.

[0115] With this configuration, at low relative rotational speeds, positive pressure is generated between the sliding surfaces 611 and 21 at the closed end 616a of the protrusion 616 and its vicinity. As the relative rotational speed increases and the distance between the sliding surfaces 611 and 21 increases, the positive pressure generated at the closed end 616a and its vicinity decreases, while positive pressure is generated at the downstream end of the upstream portion 616c of the protrusion 616 and its vicinity. In other words, the range of relative rotational speeds in which positive pressure can be generated at the protrusion 616 is widened.

[0116] In other words, the faster the relative rotational speed, the easier it is to increase the thickness of the fluid film between the sliding surfaces 611 and 21. The protrusion 616 allows for a thicker film thickness in response to an increase in the bearing characteristic number compared to the protrusion 16 in Embodiment 1, thus enabling low torque even at high load capacities.

[0117] Furthermore, the annular groove 612 is designed to facilitate the guidance of the sealed fluid F from the base 17 to the protrusion 616, as the sealed fluid F is supplied from the protrusion 616 to the sliding surfaces 611 and 21 even at low relative rotation speeds. In other words, the annular groove 612 facilitates the guidance of the sealed fluid F to the protrusion 616.

[0118] In this embodiment, a protrusion 616 with a depth that changes by one step is illustrated, but the embodiment is not limited to this. For example, as shown in Figure 9 as modified example 6-1, the depth of the protrusion may change by two or more steps, as long as the closed end is the shallowest. In other words, the portion of the protrusion upstream of the closed end may be deeper than the base.

[0119] Furthermore, the bottom surface of the protrusion may be sloped so that it becomes shallower from the upstream side to the downstream side. [Examples]

[0120] Next, the sliding parts according to Embodiment 7 will be described with reference to Figure 10. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0121] As shown in FIG. 10, the stationary seal ring 710 in Example 7 is for single rotation, similar to Example 1.

[0122] In the sliding surface 711 of the stationary seal ring 710, instead of the central land 15 in Example 1, a central land 715 is formed in the annular groove 712.

[0123] The central land 715 has a stepped shape in which the downstream portion 715a1 of the outer diameter side circumferential wall 715a protrudes inward in diameter more than the upstream portion 715a2, and the downstream portion 715b1 of the inner diameter side circumferential wall 715b protrudes outward in diameter more than the upstream portion 715b2. That is, the circumferential walls 715a and 715b are closer to each other on the downstream side than on the upstream side.

[0124] As a result, in the convex portion 716, the width W71 of the downstream portion 716b including the closed end 716a is shorter than the width W72 of the upstream portion 716c (W71 < W72). The depth of the downstream portion 716b and the depth of the upstream portion 716c are substantially the same. The flow path cross-sectional area C71 of the downstream portion 716b, which is the product of the width W71 and the depth, is narrower than the flow path cross-sectional area C72 of the upstream portion 716c, which is the product of the width W72 and the depth (C71 < C72).

[0125] With such a configuration, the central land 715 is easily guided by the circumferential walls 715a and 715b to the radially central and downstream side of the convex portion 716 for the fluid F to be sealed, so it is easy to increase the positive pressure generated at the position of the central land 715. Also, it is easy to guide the fluid F to be sealed from the base portion 17 to the convex portion 716.

[0126] Furthermore, the shape of the protrusion may be modified as appropriate, provided that the flow channel cross-sectional area on the downstream side is narrower than that on the upstream side. In other words, both side walls only need to be closer on the downstream side than on the upstream side, and may have a stepped shape with two or more steps, or only one side wall may have a stepped shape, and as shown in the circumferential walls 715Aa, 715Ab as modified example 7-1 in Figure 11, the upstream portion may have an inclined surface 715Ad that slopes from the upstream side to the downstream side and toward the radial center, the downstream portion may have an inclined surface, or the inclined surface may extend from the upstream side to the downstream side.

[0127] Furthermore, the inclined surface may extend in a straight line, a curved line, or be modified as appropriate. [Examples]

[0128] Next, the sliding parts according to Example 8 will be described with reference to Figure 12. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0129] As shown in Figure 12, the stationary sealing ring 810 in Example 8 is designed for both rotation and reversible movement, similar to Example 3.

[0130] In the stationary sealing ring 810, the sliding surface 811 has a central land 815 formed within the annular groove 812, instead of the central land 315 in the above embodiment 3.

[0131] The circumferential walls 815a and 815b in the central land 815 have a stepped shape that tapers towards the upstream side, and the downstream side is closer than the upstream side. In other words, the flow path cross-sectional area of ​​the convex portion 816F is narrower on the downstream side than on the upstream side. As a result, the central land 815 can easily increase the positive pressure generated when the rotating sealing ring 20 rotates in the forward direction, similar to the embodiment 7, and can also easily guide the fluid to be sealed F into the central land 815.

[0132] Furthermore, the protrusion 816F becomes shallower from the upstream side to the downstream side, similar to modification 6-1 in Embodiment 6. As a result, the annular groove 812 makes it easier to guide the sealed fluid F to the central land 815 when the rotating sealing ring 20 is rotating in the forward direction, similar to Embodiment 6, and also widens the range of relative rotational speeds in which positive pressure can be generated.

[0133] Furthermore, the inverted protrusion 816R is shallower from the downstream side to the upstream side, similar to modification 6-1 in Embodiment 6. As a result, the annular groove 812 makes it easier to guide the sealed fluid F to the central land 815 when the rotating sealing ring 20 rotates in the reverse direction, similar to Embodiment 6, and also widens the range of relative rotational speeds in which positive pressure can be generated. [Examples]

[0134] Next, the sliding parts according to Example 9 will be described with reference to Figure 13. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0135] As shown in Figure 13, the stationary sealing ring 910 in Example 9 is designed for unidirectional rotation, similar to Example 1.

[0136] The sliding surface 911 of the stationary sealing ring 910 has six inclined grooves 916g formed on the bottom surface of the protrusion 916. The number of inclined grooves 916g may be changed as appropriate.

[0137] Three of the inclined grooves 916g extend inclined from the outer diameter edge of the protrusion 916 toward the inner diameter and downstream. The remaining three inclined grooves 916g extend inclined from the inner diameter edge of the protrusion 916 toward the outer diameter and downstream.

[0138] With this configuration, the annular groove 912 has a geometric barrier at the edge between the bottom surface of the protrusion 916 and the upstream side surface of the inclined narrow groove 916g, making it easier to guide the sealed fluid F in the protrusion 916 towards the tip side of the inclined narrow groove 916g, that is, towards the radial center and downstream side of the protrusion 916.

[0139] This makes it easier for the sealed fluid F to concentrate in the radial center of the closed end 916a, thereby efficiently generating positive pressure at the location of the central land 15.

[0140] Furthermore, the sealed fluid F supplied between the sliding surfaces 911 and 21 from the closed end 916a and its vicinity tends to have a larger circumferential component. In other words, the movement of the sealed fluid F toward the outer space S1 or inner space S2 can be reduced, making it easier to retain the sealed fluid F between the sliding surfaces 911 and 21.

[0141] Furthermore, the annular groove 912 has a larger surface area than the annular groove 12 of Example 1 due to the presence of multiple inclined fine grooves 916g. By using a cooling fluid as the sealed fluid F, the cooling effect of the stationary sealed ring 910 can be enhanced.

[0142] Furthermore, the geometric barrier for guiding the fluid is not limited to a configuration in which grooves are formed on the bottom surface, but may also be composed of ribs formed on the bottom surface, and may be modified as appropriate. [Examples]

[0143] Next, the sliding parts according to Example 10 will be described with reference to Figure 14. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0144] As shown in Figure 14, the stationary sealing ring 1010 in Example 10 is designed for unidirectional rotation, similar to Example 1.

[0145] The sliding surface 1011 of the stationary sealing ring 1010 has 12 inclined grooves 1017g formed on the bottom surface of the base portion 1017, corresponding to the inclined grooves 916g of the above embodiment 9. The number of inclined grooves 1017g may be changed as appropriate.

[0146] With this configuration, the annular groove 1012, similar to embodiment 9, facilitates guiding the sealed fluid F within the base 1017 to the tip side of the inclined narrow groove 1017g, that is, to the radial center side and downstream side of the base 1017.

[0147] This makes it easier to hold the sealed fluid F between the sliding surfaces 1011 and 21. In addition, since the sealed fluid F tends to concentrate at the radial center of the closed end 16a, positive pressure can be efficiently generated at the position of the central land 15.

[0148] Furthermore, the annular groove 1012 has a cooling effect enhanced by multiple inclined narrow grooves 1017g, similar to the example in Example 9. [Examples]

[0149] Next, the sliding parts according to Example 11 will be described with reference to Figure 15. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0150] As shown in Figure 15, the stationary sealing ring 1110 in Example 11 is designed for unidirectional rotation, similar to Example 1.

[0151] The sliding surface 1111 of the stationary sealing ring 1110 has four inclined grooves 1118g formed on the bottom surface of the outer diameter side communicating portion 1118, and four inclined grooves 1119g formed on the bottom surface of the inner diameter side communicating portion 1119. The inclined grooves 1118g and 1119g correspond to the inclined grooves 916g of Embodiment 9. The number of inclined grooves 1118g and 1119g may be changed as appropriate.

[0152] With this configuration, the annular groove 1112 facilitates guiding the sealed fluid F within the communication portions 1118 and 1119 to the inner diameter side and downstream side of the outer diameter side communication portion 1118 or the outer diameter side and downstream side of the inner diameter side communication portion 1119, similar to the embodiment 9 described above.

[0153] This makes it easier to retain the sealed fluid F between the sliding surfaces 1111 and 21. In addition, since the sealed fluid F tends to concentrate at the radial center of the closed end 16a, positive pressure can be efficiently generated at the position of the central land 15.

[0154] Furthermore, the annular groove 1112 has a cooling effect enhanced by multiple inclined fine grooves 1118g, 1119g, similar to the example in 9 above. [Examples]

[0155] Next, the sliding parts according to Example 12 will be described with reference to Figure 16. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0156] As shown in Figure 16, the stationary sealing ring 1210 in Example 12 is designed for unidirectional rotation, similar to Example 1.

[0157] In the annular groove 1212, the protrusion 1216 defined by the central land 1215 is positioned radially closer to the inner diameter side communication portion 19 than to the outer diameter side communication portion 18, which overlaps radially.

[0158] With this configuration, the sealed fluid F supplied from the protrusion 1216 between the sliding surfaces 1211 and 21 and moving toward the inner space S2 becomes more likely to flow out into the inner space S2 beyond the inner diameter side communication portion 19. In other words, it is possible to intentionally make it easier for the sealed fluid F to leak out.

[0159] Furthermore, by positioning the protrusions closer to the outer diameter side communication portion 18 than to the inner diameter side communication portion 19 which overlaps radially, it may be easier to return the sealed fluid F to the outer space S1. [Examples]

[0160] Next, the sliding parts according to Example 13 will be described with reference to Figures 17 and 18. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0161] As shown in Figure 17, the stationary sealing ring 1410 in Example 13 is designed for unidirectional rotation, similar to Example 1.

[0162] The sliding surface 1411 of the stationary sealing ring 1410 has an overhanging wall portion 1413B as a wall portion. The overhanging wall portion 1413B is part of the outer diameter side land 1413. The overhanging wall portion 1413B has a U-shaped portion 1413B1, similar to the central land 15 in Embodiment 1, and a portion 1413B2 that extends from the outer diameter side and upstream side toward the outer diameter side and is continuous with the annular portion 1413A that extends concentrically in the outer diameter side land 1413. In other words, the wall portion may be integrated with the land that defines the annular groove.

[0163] The protruding wall portion 1413B defines a convex portion 1416 that communicates with the adjacent upstream base portion 17.

[0164] Furthermore, the protruding wall portion 1413B, together with the annular portion 1413A of the outer diameter land 1413, defines the outer diameter foot portion 1418. The outer diameter foot portion 1418 extends along the circumferential direction, and its upstream portion overlaps radially with the closed end 1416a of the convex portion 1416.

[0165] The upstream end of the outer diameter foot portion 1418 is a closed end 1418a. The downstream end of the outer diameter foot portion 1418 is open toward the downstream side and communicates with the outer diameter side of the adjacent downstream base portion 17.

[0166] With this configuration, when the rotating sealing ring 20 rotates relative to another, the sealed fluid F that moves from the protrusion 1416 towards the outer space S1 flows into the outer diameter foot portion 1418, thereby inhibiting its movement. In other words, it is easier to retain the sealed fluid F within the annular groove 1412.

[0167] Furthermore, since negative pressure is generated at the closed end 1418a side of the outer diameter foot portion 1418, the sealed fluid F that has flowed out from the protrusion 1416 or base portion 17 to the protruding wall portion 1413B is easily drawn into the outer diameter foot portion 1418.

[0168] In this embodiment, a configuration in which an outer diameter side foot portion is formed instead of an outer diameter side communication portion has been illustrated, but the embodiment is not limited to this, and an inner diameter side foot portion, which is closed on the upstream side, may be formed on the inner diameter side of the protrusion. In other words, the protruding wall portion may have a U-shaped portion and a portion that extends from the inner diameter side and upstream side of the U-shaped portion toward the inner diameter side and is continuous with the annular portion of the inner diameter side land.

[0169] Furthermore, although the protrusion 1416 in this embodiment is provided in the radial center, similar to Embodiment 1, it is not limited to this, and the sealed fluid F may be intentionally made more likely to leak by forming it on the inner diameter side of the communication portion 19 rather than the outer diameter side foot portion 1418, for example, as shown in the modified example 13-1, of the protrusion 1416A in Figure 18. Thus, the radial position of the protrusion defined by the overhanging wall portion may be changed as appropriate, as in Embodiment 12, and may be formed on the outer diameter side of the foot portion 1418, for example. [Examples]

[0170] Next, the sliding parts according to Example 14 will be described with reference to Figure 19. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0171] As shown in Figure 19, the stationary sealing ring 1610 in Example 14 is designed for unidirectional rotation, similar to Example 1.

[0172] In the stationary sealing ring 1610, the sliding surface 1611 has a central land 1615 formed within the annular groove 1612, instead of the central land 15 in the first embodiment.

[0173] The central land 1615 is formed in a V-shape when viewed from the axial direction and has an outer diameter inclined wall 1615a that extends inclined from the upstream side to the downstream side and toward the inner diameter side, and an inner diameter inclined wall 1615b that extends inclined from the upstream side to the downstream side and toward the outer diameter side. The downstream end of the outer diameter inclined wall 1615a and the downstream end of the inner diameter inclined wall 1615b are continuous at the radial center of the annular groove 1612.

[0174] The convex portion 1616, defined by the central land 1615, has the shape of an isosceles triangle that narrows from the upstream side to the downstream side and towards the radial center.

[0175] With this configuration, as in Embodiment 7, the central land 1615 is designed to easily guide the sealed fluid F radially towards the center and downstream side by the inclined walls 1615a and 1615b, thereby increasing the positive pressure generated at and near the closed end 1616a. Furthermore, it facilitates the guidance of the sealed fluid F from the base 17 to the protrusion 1616, that is, to the central land 1615.

[0176] Furthermore, the outer diameter side inclined wall 1615a is spaced further away from the outer diameter side land 13 as it moves downstream. The outer diameter side communication portion 1618 is wider towards the downstream side and towards the radial center. As a result, the sealed fluid F moving from the protrusion 1616 towards the outer space S1 is more likely to flow into the outer diameter side communication portion 1618 of this embodiment at a position closer to the inner diameter than the outer diameter side communication portion 18 of the above embodiment.

[0177] Furthermore, the upstream end of the outer diameter side inclined wall 1615a is as close to the outer diameter side land 13 as the outer diameter side circumferential wall 15a in Embodiment 1. Therefore, similar to the outer diameter side circumferential wall 15a in Embodiment 1, it is easier to guide the sealed fluid F flowing downstream within the adjacent upstream base portion 17 to the convex portion 1616 rather than the outer diameter side communication portion 1618.

[0178] The same applies to the inner diameter inclined wall 1615b and the inner diameter connecting section 1619.

[0179] On the other hand, from the viewpoint of easily generating positive pressure over a sufficient range, the central land 15 of Example 1 is preferable.

[0180] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0181] For example, in the above embodiments 1 to 14, it was explained that the annular grooves and walls are formed in a stationary sealing ring, but the invention is not limited to this, and they may also be formed in a rotating sealing ring, or they may be formed in both a stationary sealing ring and a rotating sealing ring.

[0182] Furthermore, the fluid used for lubrication may be a liquid or a gas, or it may be a mist-like mixture of liquid and gas. [Explanation of Symbols]

[0183] 1. Axis of rotation 4 Housing 10 Stationary sealing ring 11. Sliding surface (one of the sliding surfaces) 12 Annular groove 15 Central Land (Wall Section) 15a,15b Circumferential wall 17 Base 18,19 Communication part 20 Rotating Sealing Rings 21. Sliding surface (the other sliding surface) A atmosphere F Sealed fluid S1 outside space S2 inner space

Claims

1. A sliding component in which a pair of sliding surfaces are positioned at a location where they rotate relative to each other, and which separates an outer space from an inner space, A sliding component having at least one of the sliding surfaces an annular groove and a wall portion provided within the annular groove that generates positive pressure.

2. The wall portion has a side wall extending in the circumferential direction on at least one of the outer diameter side and the inner diameter side, The sliding component according to claim 1, wherein the annular groove has a base portion located relative to the wall portion on the upstream side of the relative rotation, and a protrusion portion narrower than the base portion that the side wall faces and is connected to the base portion.

3. The sliding component according to claim 2, wherein the cross-sectional area of ​​the flow path on the downstream side of relative rotation is narrower than the cross-sectional area on the upstream side of relative rotation.

4. The sliding component according to claim 2, wherein the wall portions are arranged in a plurality in the circumferential direction, and the annular groove has a connecting portion that connects adjacent base portions in the circumferential direction.

5. The sliding component according to claim 4, wherein the communicating portion is provided on the outer space side and the inner space side of the wall portion, respectively.

6. The sliding component according to claim 5, wherein the radial length of the wall portion is longer than the sum of the radial length of the communication portion on the inner space side and the radial length of the communication portion on the outer space side.

7. The sliding component according to claim 4, wherein the depth of the annular groove is shallower than the depth of the base, at least on the downstream side of the convex portion in relative rotation.

8. The sliding component according to claim 2, wherein a guide groove is provided within the annular groove, inclined to extend from the upstream side of relative rotation toward the radial center of the protrusion and toward the downstream side of relative rotation.

9. The sliding component according to any one of claims 1 to 8, wherein the wall portion extends toward the other sliding surface so as to be in sliding contact with the other sliding surface.

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