Sliding component

Abstract

Provided is a sliding component capable of smoothing fluid flow.　A sliding component S comprises: a housing-side slide ring 10 that is fixed to a housing 4 and has a communication passage 10A that communicates with a flow passage 4a of the housing 4; and a shaft-side slide ring 20 that is fixed to a shaft 1 inserted into the housing 4 and has a communication passage 20A that communicates with a flow passage 1a of the shaft 1 and is communicable with the communication passage 10A of the housing-side slide ring 10. A fluid F can flow from one flow passage 4a to the other flow passage 1a, and a slide surface 11 of the housing-side slide ring 10 and a slide surface 21 of the shaft-side slide ring 20 rotate relative to each other. The communication passage 20A of the rotating-side slide ring 20 among the housing-side slide ring 10 and the shaft-side slide ring 20 has an inclined wall 23 that is inclined relative to the axial direction.

Description

Sliding component

[0001] The present invention relates to sliding components that rotate relative to each other, and more particularly to sliding components that enable fluid to flow between a housing and a rotating shaft through, for example, a fixed sealing ring and a rotating sealing ring.

[0002] In a relative rotation portion of a rotating machine, a sliding component having a rotating ring and a stationary ring whose sliding surfaces slide against each other is disposed. Such a sliding component is applied to a rotary joint that connects a stationary-side pipe and a rotating-side pipe in a communicable manner.

[0003] For example, the sliding component shown in Patent Document 1 includes a stationary ring fixed to a housing and having a communication passage communicating with the flow passage of the housing, and a rotating ring fixed to a rotating shaft and having a communication passage communicating with the flow passage of the rotating shaft. The communication passage of the stationary ring extends axially from the back side toward the sliding surface side. The communication passage of the rotating ring is disposed at a position corresponding radially to the communication passage of the stationary ring, and extends axially from the sliding surface side toward the back side. The flow passage of the housing, the communication passage of the stationary ring, the communication passage of the rotating ring, and the flow passage of the rotating shaft are in communication regardless of whether the stationary ring and the rotating ring are rotating or stopped. The fluid in the flow passage of the housing flows into the flow passage of the rotating shaft through the communication passage of the stationary ring and the communication passage of the rotating ring by means of an external pump or the like.

[0004] Microfilm of Japanese Utility Model Application No. Sho 60-127874 (Published as Japanese Utility Model Laid-Open No. Sho 62-37687), page 3, figure 2

[0005] However, in the rotary joint of Patent Document 1, since fluid is pumped out from the upstream side of a series of flow passages using an external pump, the fluid delivery capacity on the downstream side of the series of flow passages becomes insufficient due to fluid loss caused by the length and shape of the series of flow passages, and there is a risk of fluid stagnation.

[0006] The present invention has been made paying attention to such problems, and an object thereof is to provide a sliding component that can smooth the flow of fluid.

[0007] To solve the aforementioned problems, the present invention provides a sliding component comprising: a housing-side sliding ring fixed to a housing and having a passage that communicates with a flow path in the housing; and a shaft-side sliding ring fixed to a shaft inserted through the housing and having a passage that communicates with a flow path in the shaft and can communicate with the passage of the housing-side sliding ring, wherein fluid can flow from one flow path to the other, and the sliding surface of the housing-side sliding ring and the sliding surface of the shaft-side sliding ring rotate relative to each other, wherein the passages of the housing-side sliding ring and the rotating side of the shaft-side sliding ring are provided with inclined walls that are inclined with respect to the axial direction. As a result, as the rotating side sliding ring rotates, the inclined walls push the fluid downstream, allowing fluid to flow smoothly from one flow path to the other.

[0008] The connecting passage of the sliding ring on the rotating side may have multiple through holes defined in the circumferential direction by the inclined wall. This allows fluid to flow efficiently through the multiple through holes.

[0009] The inclined walls may be equally spaced in the circumferential direction. This allows the fluid to be output uniformly in the circumferential direction.

[0010] An annular groove may be formed on the sliding surface side of the communication passage of the rotating sliding ring. This allows fluid to be constantly sent to the downstream side regardless of the phase of the communication passage of the rotating sliding ring. Furthermore, interference between the inclined wall and the stationary sliding ring during relative rotation can be avoided.

[0011] The annular groove may taper toward the communication passage of the sliding ring on the rotating side. This allows the fluid to be guided toward the communication passage of the sliding ring on the rotating side.

[0012] The inclined wall may be spiral-shaped. This allows the fluid to be efficiently delivered to the downstream side.

[0013] A dynamic pressure generating groove may be provided on at least one of the sliding surfaces of the rotating sliding ring and the stationary sliding ring. This improves the sliding performance between the rotating sliding ring and the stationary sliding ring.

[0014] This is a longitudinal cross-sectional view showing a rotary joint in Embodiment 1 of the present invention. (a) is a view of the stationary sealing ring from the sliding surface side, and (b) is a view of the same from the rear side. (a) is a view of the rotating sealing ring from the sliding surface side, and (b) is a cross-sectional view of (a) along A-A. This is a schematic diagram showing the state in which fluid flows through a series of flow paths. This is a schematic diagram showing the fluid flow near the sliding surfaces during relative rotation. This is a view of the rotating sealing ring in Embodiment 2 of the present invention from the sliding surface side. This is a schematic diagram showing a rotary joint in Embodiment 3 of the present invention. This is a schematic diagram showing the shape of the annular groove in Embodiment 4 of the present invention. This is a schematic diagram showing a modified example of Embodiment 4. This is a view of the rotating sealing ring in Embodiment 5 of the present invention from the sliding surface side. This is a schematic diagram showing a modified example in the direction of fluid flow. This is a longitudinal cross-sectional view showing a modified example when the housing-side sliding ring rotates.

[0015] Embodiments for implementing the sliding component according to the present invention will be described below based on examples.

[0016] The sliding component according to Embodiment 1 will be described with reference to Figures 1 to 6. Hereinafter, the front side of Figure 1 will be considered the front side of the sliding component, and the left and right sides as viewed from the front will be considered the left and right sides of the sliding component. In this embodiment, a mechanical seal S will be used as an example of the sliding component. Furthermore, in Figure 3(a), dots have been added to the side surface of the wall portion 23 for the sake of explanation.

[0017] The rotary joint shown in Figure 1 mainly consists of a housing 4 of the equipment to be attached, a rotating shaft 1 as an axis rotatably inserted into the housing 4, and a mechanical seal S positioned at the relative rotation points of these. Multiple flow channels 4a extending in the axial direction are formed in the circumferential direction of the housing 4. Multiple flow channels 1a extending in the axial direction are also formed in the circumferential direction of the rotating shaft 1.

[0018] The mechanical seal S seals the fluid F that flows through the approximate radial center of the sliding surface. In this embodiment, the fluid F is used to cool the housing 4 and the rotating shaft 1. Furthermore, this fluid F can be freely changed depending on the application.

[0019] The mechanical seal S mainly consists of a stationary sealing ring 10 as a sliding ring on the housing side and a rotating sealing ring 20 as a sliding ring on the shaft side. The stationary sealing ring 10 is annular in shape and is provided on the inner diameter side of the housing 4 in a non-rotating state and movable in the axial direction. Specifically, the convex piece 4d of the housing 4 fits into a notched recess 10a provided on the outer diameter side of the stationary sealing ring 10, thereby enabling it to move in the axial direction and not rotate. The rotating sealing ring 20 is annular in shape and is provided in a state that allows it to rotate together with the rotating shaft 1 by being sandwiched in the axial direction between a sleeve 5 fixed to the rotating shaft 1 and a stepped portion 1d of the rotating shaft 1.

[0020] The inner diameter end faces 4b and 4c of the housing 4 are positioned such that the inner diameter end face 4c is spaced further inward than the outer diameter end face 4b, and the end face 4c is positioned to the right of the end face 4b.

[0021] An elastic member 7 is positioned between the end faces 4b and 4c of the housing 4 and the right side, i.e., the back surface, of the stationary sealing ring 10, and the stationary sealing ring 10 is biased in the axial direction by the elastic member 7. This elastic member 7 causes the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 to slide in close contact with each other.

[0022] The elastic member 7 is a double bellows composed of a metal outer bellows 71 and an inner bellows 72. The annular internal space 7a between the outer bellows 71 and the inner bellows 72 communicates with each of the flow channels 4a of the housing 4. In other words, the internal space 7a constitutes a part of the flow channels 4a of the housing 4.

[0023] Furthermore, the elastic member 7 may or may not be fixed to the back surface of the stationary sealing ring 10 by welding or the like, as long as the space between the internal space 7a and the communication passage 10A of the stationary sealing ring 10 (described later) is sealed. For example, in environments where the outer bellows 71 and inner bellows 72 are prone to deformation or vibrations are likely to occur, it is preferable that the elastic member 7 is not fixed so that it can easily follow the movement of the stationary sealing ring 10.

[0024] The stationary sealing ring 10 and the rotating sealing ring 20 are typically formed from two SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but are not limited to these; any sliding material used as a sliding material for mechanical seals is applicable. SiC can be sintered using boron, aluminum, carbon, etc. 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, SiC-TiN, etc. Carbon can be a mixture of carbonaceous and graphite, as well as resin-molded carbon, sintered carbon, etc. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc., are also applicable.

[0025] As shown in Figures 1 and 2(a) and 2(b), the stationary sealing ring 10 includes an annular groove 12 on the sliding surface side, an annular groove 13 on the back side, and a plurality of through holes 14.

[0026] The sliding surface-side annular groove 12 is provided on the sliding surface 11 of the stationary sealing ring 10 in a manner substantially concentric with the sliding surface 11. This sliding surface-side annular groove 12 has a substantially U-shaped cross-section that opens toward the sliding surface 21 side of the rotating sealing ring 20. The left end of the sliding surface-side annular groove 12 communicates with the communication passage 20A of the rotating sealing ring 20, which will be described later.

[0027] The rear annular groove 13 is provided on the back surface of the stationary sealing ring 10, substantially concentric with the back surface. This rear annular groove 13 has a substantially U-shaped cross-section that opens toward the elastic member 7. The right end of the rear annular groove 13 communicates with the internal space 7a of the elastic member 7.

[0028] The through-holes 14 extend axially, connecting the bottom surface of the sliding surface-side annular groove 12 and the bottom surface of the back-side annular groove 13. Multiple through-holes 14 are evenly spaced in the circumferential direction (for example, eight in this embodiment).

[0029] In other words, the sliding surface-side annular groove 12, the rear-side annular groove 13, and the through-hole 14 function as a communication passage 10A for the stationary sealing ring 10 that communicates with the flow path 4a of the housing 4.

[0030] Furthermore, the parts of the sliding surface 11 of the stationary sealing ring 10 other than the sliding surface side annular groove 12 are flat lands.

[0031] As shown in Figures 1 and 3(a) and 3(b), the rotating sealing ring 20 has a communication passage 20A in which a plurality of through holes 28 are equally spaced in the circumferential direction. Each through hole 28 is provided in the same number as the plurality of circumferential flow paths 1a provided on the rotating shaft 1, and communicates in the axial direction (see Figure 5).

[0032] As shown in Figure 3(a), the through hole 28 extends with a circumferential inclination when viewed from the axial direction. As shown in Figure 3(b), the through hole 28 extends linearly from right to left, with a circumferential inclination toward the downstream side in the rotational direction of the rotating sealing ring 20 when viewed from the radial direction.

[0033] Furthermore, the rotating sealing ring 20 is provided with wall portions 23 as inclined walls between adjacent through holes 28 in the circumferential direction. The multiple wall portions 23 are arranged alternately with the multiple through holes 28 in the circumferential direction. In other words, the communication passage 20A is provided with multiple wall portions 23. The communication passage 20A is also defined by the multiple wall portions 23, which define multiple through holes 28 in the circumferential direction.

[0034] As shown in Figure 3(a), the wall portion 23 extends with an inclination in the circumferential direction when viewed from the axial direction. As shown in Figure 3(b), the wall portion 23 extends linearly from the right to the left, with an inclination in the circumferential direction toward the downstream side in the rotational direction of the rotating sealing ring 20 when viewed from the radial direction. Since each wall portion 23 is arranged parallel to the others, the circumferential width W1 of the through hole 28 is constant in the axial direction.

[0035] Furthermore, the circumferential width W2 of the wall portion 23 is greater than the circumferential width W1 of the through hole 28 (W1 < W2). This ensures the strength of the rotating sealing ring 20 and the wall portion 23.

[0036] Furthermore, as shown in Figures 3(a) and 3(b), the sliding surface 21 of the rotating sealing ring 20 is provided with an outer diameter land 24 and an inner diameter land 25, and an annular groove 22 is formed between the outer diameter land 24 and the inner diameter land 25 in the radial direction, which is substantially concentric with the sliding surface 21.

[0037] The annular groove 22 has a roughly U-shaped cross-section that opens toward the sliding surface 11 of the stationary sealing ring 10. A through hole 28 is provided at the bottom of the annular groove 22. In other words, the annular groove 22 is in communication with the through hole 28.

[0038] Referring to Figure 4, in this embodiment, the rotary joint is pumped to the left by an external pump (not shown) located on the right side of the flow path 4a of the housing 4. The fluid F pumped by the external pump flows through the flow path 4a of the housing 4, the internal space 7a, the communication passage 10A of the stationary sealing ring 10, and the communication passage 20A of the rotating sealing ring 20 to the flow path 1a of the rotating shaft 1. The fluid F in the flow path 1a of the rotating shaft 1 is returned to the external pump side and circulates throughout the entire series of flow paths.

[0039] During relative rotation between the rotating shaft 1 and the housing 4, the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 slide relative to each other, preventing fluid F from leaking from between the sliding surfaces 11 and 21 to the outer space S1 and the inner space S2.

[0040] As shown in Figures 4 and 5, the fluid F flowing from the communication passage 10A of the stationary sealing ring 10 toward the communication passage 20A of the rotating sealing ring 20 is pushed toward the flow path 1a of the rotating shaft 1 by each rotating wall portion 23. In other words, each wall portion 23 functions as a rotor, allowing the fluid F to flow smoothly toward the downstream side.

[0041] According to this, even if fluid loss of fluid F occurs in the flow path 4a, internal space 7a, etc. of the housing 4, each wall portion 23 functions as a rotor, promoting the flow of fluid F downstream and suppressing fluid F stagnation. For example, it is possible to avoid a decrease in the cooling function of the housing 4 and rotating shaft 1 due to fluid F, and to easily discharge contaminants mixed in the fluid F through the series of flow paths.

[0042] Furthermore, multiple through-holes 28 are defined in the circumferential direction by multiple wall portions 23, and the fluid F can be efficiently delivered to the downstream side by passing through each through-hole 28.

[0043] In addition, since the wall portions 23 are equally distributed in the circumferential direction, the momentum of the fluid F can be made uniform in the circumferential direction. Therefore, the flow of the fluid F on the downstream side becomes smooth.

[0044] Further, since the wall portion 23 extends from the right side to the left side while inclining in the circumferential direction toward the relatively rotating downstream side of the rotary seal ring 20 when viewed from the radial direction, it is easy to catch the fluid F flowing from the right side to the left side with the wall portion 23, and the fluid F can be efficiently sent to the downstream side while being pressurized.

[0045] Further, on the upstream side of the communication passage 20A of the rotary seal ring 20, the sliding surface side annular groove 12 and the annular groove 22 are formed in the communication passage 10A of the stationary seal ring 10. According to this, regardless of the phase of each through hole 28 of the rotary seal ring 20, each through hole 28 is always in communication with the sliding surface side annular groove 12 and the annular groove 22, so that the fluid F can always be sent to the downstream side without being retained. Further, it is possible to avoid interference with the sliding surface 11 of the stationary seal ring 10 when the rotary seal ring 20 rotates. Incidentally, on the upstream side of the communication passage 20A of the rotary seal ring 20, either the sliding surface side annular groove 12 and the annular groove 22 may be provided and the other configuration may be omitted, or both may be omitted.

[0046] Further, the through holes 28 of the rotary seal ring 20 have a constant circumferential width W1 in the axial direction, that is, a constant flow path cross section in the axial direction, and no throttle portion or the like is formed in the through holes 28, so that the fluid F can flow smoothly to the downstream side.

[0047] Further, the internal space 7a of the elastic member 7 constituting a part of the flow path 4a of the housing 4 is composed of an outer bellows 71 and an inner bellows 72, and the elastic member 7 expands and contracts due to vibration or the like, so that the fluid F can be directly pressed. Therefore, the fluid F can hit the wall portion 23 at a high pressure and the fluid can be introduced more efficiently.

[0048] Further, since the outer bellows 71 and the inner bellows 72 are made of metal, for example, in a low temperature environment or when the fluid F is at a low temperature, it is easier to maintain the followability with respect to the stationary seal ring 10 than a secondary seal made of rubber or the like, so that leakage of the fluid F can be suppressed.

[0049] Furthermore, the annular members 71a and 72a, which are fixed to the left end of the outer bellows 71 and the left end of the inner bellows 72 respectively, are not fixed to the stationary sealing ring 10. As a result, the deformation of the outer bellows 71 and the inner bellows 72 is not directly transmitted to the stationary sealing ring 10, so even if the biasing force of the outer bellows 71 and the inner bellows 72 differs instantaneously, the stationary sealing ring 10 is less likely to tilt. Note that the annular members 71a and 72a may be fixed to the stationary sealing ring 10.

[0050] In this embodiment, the flow path 1a of the rotating shaft 1 is an example in which a through hole with a circular cross-section is provided in multiple locations in the circumferential direction. However, the embodiment is not limited to this, and for example, the flow path of the rotating shaft may be an arc-shaped groove or an annular groove extending in the circumferential direction. In other words, it is not limited to the case that one through hole of the rotating sealing ring corresponds to one flow path of a rotating shaft, but rather that multiple through holes of the rotating sealing ring are in communication with each other for one flow path of a rotating shaft.

[0051] Furthermore, although this embodiment illustrates a configuration in which the wall portion 23 is inclined in the circumferential direction when viewed from the axial direction, the inclined wall may also extend radially when viewed from the axial direction.

[0052] Next, the sliding parts according to Embodiment 2 will be described with reference to Figure 6. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted. For the sake of clarity, dots have been added to the wall portion 223.

[0053] As shown in Figure 6, the wall portion 223 of the rotating sealing ring 220 in this embodiment 2 extends axially while twisting in a spiral shape. That is, the through hole 228 is inclined circumferentially with respect to the axial direction and extends spirally. As a result, the angle of the wall portion 223 (i.e., the through hole 228) changes gradually, so that the flow of the fluid F is smoothly guided, the generation of vortices is suppressed, and the fluid can be efficiently sent to the downstream side.

[0054] Furthermore, since the circumferential width of the wall portion 223 in this embodiment 2 is smaller than the circumferential width of the through hole 228, a large opening area for each through hole 228 can be secured in the circumferential direction.

[0055] The twist angle of the wall portion 223 can be freely changed, but a twist angle of about 10 to 40 degrees is preferred.

[0056] Next, the sliding parts according to Embodiment 3 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.

[0057] As shown in Figure 7, the stationary sealing ring 310 of this embodiment 3 is composed of an outer diameter annular member 316 and an inner diameter annular member 317. The space between the outer diameter annular member 316 and the inner diameter annular member 317 forms a connecting passage 310A. The outer diameter annular member 316 is prevented from rotating by a protrusion 4d of the housing 4 fitting into a notched recess 316a provided on the outer diameter side, and the inner diameter annular member 317 is prevented from rotating by a protrusion 4e of the housing 4 fitting into a notched recess 317a provided on the inner diameter side.

[0058] According to this, the communication passage 310A that communicates with the internal space 7a of the elastic member 7 can be configured in an annular shape, so no portion is formed separating the internal space 7a and the communication passage 310A. In other words, a large circumferential communication area between the internal space 7a and the communication passage 310A can be secured, so fluid loss between the internal space 7a and the communication passage 310A is suppressed, and fluid F stagnation can be prevented. Similarly, a large communication area between the rotating sealing ring 320 and the communication passage can also be secured.

[0059] Next, the sliding parts according to Embodiment 4 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.

[0060] As shown in Figure 8, in this embodiment 4, the stationary sealing ring 410 has a sliding surface-side annular groove 412 that tapers toward the communication passage 420A (i.e., through hole 428) of the rotating sealing ring 420. Specifically, the outer surface 412a constituting the sliding surface-side annular groove 412 is an inclined surface that slopes toward the inner diameter from the right to the left, and the inner surface 412b constituting the sliding surface-side annular groove 412 is an inclined surface that slopes toward the outer diameter from the right to the left.

[0061] According to this design, the fluid F flowing into the sliding surface-side annular groove 412 from the right is guided by the outer surface 412a and inner surface 412b toward the communication passage 420A of the left-side rotating sealing ring 420, thereby allowing the fluid F to be smoothly delivered downstream. Furthermore, since no step is formed between the sliding surface-side annular groove 412 of the stationary sealing ring 410 and the through hole 428 of the rotating sealing ring 420, the formation of vortices can be avoided.

[0062] Furthermore, as described later, when fluid flows from the communication passage of the rotating sealing ring toward the communication passage of the stationary sealing ring (see Figure 11), the outer and inner surfaces of the annular groove 422' of the rotating sealing ring 420' may taper toward the communication passage 410A' of the stationary sealing ring 410', as shown in Figure 9.

[0063] Alternatively, instead of forming an annular groove, the edges of the through holes in the rotating sealing ring and the through holes in the stationary sealing ring, which have different diameters, may be tapered to be continuous.

[0064] Next, the sliding component according to Embodiment 5 will be described with reference to Figure 10. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted. In Figure 10, the rotation direction of the rotating sealing ring is indicated by a dashed arrow. Also, for the sake of clarity, dots are added to the wall surface.

[0065] As shown in Figure 10, multiple outer diameter side dynamic pressure generating grooves 526 are provided circumferentially on the outer diameter side land 524 of the sliding surface 521 of the rotating sealing ring 520. In addition, multiple inner diameter side dynamic pressure generating grooves 527 are provided circumferentially on the inner diameter side land 525. The outer diameter side dynamic pressure generating grooves 526 and the inner diameter side dynamic pressure generating grooves 527 are in communication with the annular groove 522.

[0066] The outer diameter side dynamic pressure generating groove 526 is a spiral groove that extends in an arc shape from the inner diameter side to the outer diameter side, inclined toward the upstream side in the rotational direction of the rotating sealing ring 520. The outer diameter side dynamic pressure generating groove 526 is provided on the inner diameter side of the outer diameter side land 524, that is, close to the communication passage 520A (through hole 528) of the rotating sealing ring 520.

[0067] In this embodiment 5, the inner diameter end of the outer diameter side dynamic pressure generating groove 526 is in communication with the annular groove 522, but it may be separated from the annular groove 522 by a land.

[0068] The inner diameter side dynamic pressure generating groove 527 is a spiral groove that extends in an arc shape from the outer diameter side to the inner diameter side, inclined toward the upstream side in the rotational direction of the rotating sealing ring 520. The inner diameter side dynamic pressure generating groove 527 is provided on the outer diameter side of the inner diameter side land 525, that is, close to the communication passage 520A (through hole 528) of the rotating sealing ring 520.

[0069] In this embodiment 5, the outer diameter end of the inner diameter side dynamic pressure generating groove 527 is in communication with the annular groove 522, but it may be separated from the annular groove 522 by a land.

[0070] As the rotating sealing ring 520 rotates, the fluid supplied from the stationary sealing ring side through the annular groove 522 into the outer diameter side dynamic pressure generating groove 526 and the inner diameter side dynamic pressure generating groove 527 moves downstream in the relative rotation direction due to relative sliding with the stationary sealing ring, generating dynamic pressure at the outer diameter end 526a of the outer diameter side dynamic pressure generating groove 526 and the inner diameter end 527a of the inner diameter side dynamic pressure generating groove 527. This dynamic pressure causes the sliding surfaces to float, improving sliding performance.

[0071] Furthermore, when generating dynamic pressure by providing a dynamic pressure generating groove on the sliding surface, as in this embodiment, it is preferable that the bellows and the stationary sealing ring are not fixed but can move relative to each other, as in Embodiment 1 described above, in order to reliably generate dynamic pressure.

[0072] In this embodiment 5, the dynamic pressure generating groove is shown as a spiral groove, but it may also be a dimple or Rayleigh step.

[0073] Furthermore, the dynamic pressure generating groove only needs to be provided on either the outer diameter land or the inner diameter land.

[0074] Furthermore, the dynamic pressure generating groove is not limited to being provided in the rotating sealing ring, but may also be provided in the stationary sealing ring, or in both. Also, as will be described later, when fluid flows from the communication passage of the rotating sealing ring toward the communication passage of the stationary sealing ring (see Figure 11), it goes without saying that dynamic pressure is generated by the fluid supplied from the rotating sealing ring side.

[0075] 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.

[0076] For example, in the above embodiments 1 to 5, a configuration in which multiple inclined walls are provided was illustrated, but it is sufficient to provide at least one, and the number can be freely changed.

[0077] Furthermore, while embodiments 1 to 5 above illustrate configurations in which the inclined walls are equally spaced, the arrangement of the inclined walls can be freely changed.

[0078] Furthermore, while embodiments 1 to 5 illustrate configurations in which an annular groove is formed on both the stationary ring and the rotating ring, it is sufficient for an annular groove to be formed on at least one side. On the other hand, a configuration in which an annular groove is formed on the rotating ring side and a connecting passage is provided downstream of the annular groove is preferable from the viewpoint of ensuring that the annular groove is reliably located upstream of the connecting passage on the rotating ring.

[0079] Furthermore, while embodiments 1 to 5 illustrate a configuration in which the fluid flows from the housing side to the rotating shaft side, the invention is not limited to this configuration. As shown in Figure 11, the fluid F may flow from the flow path 1a of the rotating shaft 1 to the flow path 4a of the housing 4. In this case, the fluid F flows through the flow path 1a of the rotating shaft 1, the communication passage 20A of the rotating sealing ring 20, the communication passage 10A of the stationary sealing ring 10, and the internal space 7a to the flow path 4a of the housing 4. The fluid F flowing from the communication passage 20A of the rotating sealing ring 20 toward the communication passage 10A of the stationary sealing ring 10 is pushed toward the flow path 4a of the housing 4 by the rotating walls 23, allowing the fluid F to flow smoothly toward the downstream side.

[0080] Furthermore, although the above embodiments 1 to 5 described the housing as the stationary side and the shaft as the rotating side, the invention is not limited to this configuration. As shown in Figure 12, the housing 604 may rotate relative to the fixed shaft 601. In this case, it is sufficient that the housing-side sliding ring 620 is provided with an inclined wall 623. The rotating inclined wall 623 can then pump the fluid downstream.

[0081] Furthermore, although the sliding parts were described as mechanical seals that seal fluids in the above-described embodiments 1 to 5, they may also be used in fields such as bearings.

[0082] 1 Rotating shaft (shaft) 1a Flow path 4 Housing 4a Flow path 7 Elastic member 7a Internal space 10 Stationary sealing ring (housing-side sliding ring) 10A Connecting passage 11 Sliding surface 12 Sliding surface-side annular groove (annular groove) 20 Rotating sealing ring (shaft-side sliding ring) 20A Connecting passage 21 Sliding surface 22 Annular groove 23 Wall portion (inclined wall) 28 Through hole F Fluid S Mechanical seal (sliding part)

Claims

1. A sliding component comprising: a housing-side sliding ring fixed to a housing and having a passage that communicates with a flow path in the housing; and a shaft-side sliding ring fixed to a shaft inserted through the housing and having a passage that communicates with a flow path in the shaft and is also able to communicate with the passage of the housing-side sliding ring, wherein fluid can flow from one flow path to the other, and the sliding surface of the housing-side sliding ring and the sliding surface of the shaft-side sliding ring rotate relative to each other, wherein the passages of the housing-side sliding ring and the rotating sliding ring of the shaft-side sliding ring are provided with inclined walls that are inclined with respect to the axial direction.

2. The sliding component according to claim 1, wherein the communication passage of the rotating sliding ring is defined in the circumferential direction by the inclined wall, comprising a plurality of through holes.

3. The sliding component according to claim 2, wherein the inclined walls are equally spaced in the circumferential direction.

4. The sliding component according to claim 1, wherein an annular groove is formed on the sliding surface side of the communication passage of the rotating sliding ring.

5. The sliding component according to claim 4, wherein the annular groove tapers toward the communication passage of the sliding ring on the rotating side.

6. The sliding component according to claim 1, wherein the inclined wall is spiral-shaped.

7. The sliding component according to claim 1, wherein at least one of the sliding surfaces of the rotating sliding ring and the stationary sliding ring is provided with a dynamic pressure generating groove.

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