Sliding parts

Abstract

Provided is a sliding component capable of preventing poor lubrication between sliding surfaces during low-speed relative rotation.　In this sliding component in which a pair of sliding rings 10, 20 rotate relative to each other and partition a first fluid space S1 and a second fluid space S2, a sliding surface of corresponding one of the pair of sliding rings 10, 20 has: a specific dynamic pressure generation groove 16 that is provided on the first fluid space S1 side and that generates dynamic pressure by means of a first fluid F; a dynamic pressure generation groove 15 that is provided closer to the second fluid space S2 side as compared to the specific dynamic pressure generation groove 16 and that generates dynamic pressure by means of a second fluid A; a communication groove 131 in communication with the first fluid space S1; a circumferential-direction groove 132 provided closer to the second fluid space S1 side as compared to the specific dynamic pressure generation groove 16 and extending in the circumferential direction from the communication groove 131; and a first fluid introduction groove 14 which is provided closer to the second fluid space S2 side as compared to the circumferential-direction groove 132 and through which the first fluid F is introduced.

Description

[Technical Field]

[0001] The present invention relates to a sliding part that rotates relative to another sliding part, such as a sliding part used in a shaft sealing device that seals the rotating shaft of a rotating machine in an automobile, general industrial machine, or other sealing field, or a sliding part used in a bearing of a machine in an automobile, general industrial machine, or other bearing field. [Background technology]

[0002] Mechanical seals, for example, are shaft sealing devices that prevent leakage of sealed fluids and are equipped with a pair of annular sliding components that rotate relative to one another and have sliding surfaces that slide against each other. In recent years, there has been a demand for reducing the energy lost due to sliding in such mechanical seals, for environmental reasons.

[0003] For example, the mechanical seal shown in Patent Document 1 has a fluid inlet groove, a Rayleigh step, and a dynamic pressure generating groove provided on the sliding surface of the rotating seal ring. The fluid inlet groove is a deep groove that communicates with the liquid space on the outer diameter side and extends in the radial direction. The Rayleigh step is a shallow groove that communicates with the fluid inlet groove and extends circumferentially toward the downstream side in the direction of rotation. The dynamic pressure generating groove is a spiral groove that communicates with the gas space on the inner diameter side and extends toward the outer diameter side while inclining toward the downstream side in the direction of rotation.

[0004] In this mechanical seal, when the rotating seal ring is rotating at low speeds, liquid is introduced between the sliding surfaces from the fluid introduction groove, and the sliding surfaces are liquid-lubricated, thereby improving slidability. Also, when the rotating seal ring is rotating at high speeds, such as during steady operation, gas is introduced from the inner diameter end of the dynamic pressure generating groove, generating dynamic pressure near the closed end, which causes a slight separation between the sliding surfaces and gas-lubrication between the sliding surfaces, thereby improving slidability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO 2016 / 167262 (page 13, Figure 7) Summary of the Invention [Problem to be solved by the invention]

[0006] In a mechanical seal such as that described in Patent Document 1, the pressure in the gas space may change and become higher than the pressure in the liquid space. In such a case, when the rotating seal ring rotates at a low speed, a large amount of gas flows from the gas space into the space between the sliding surfaces, and the gas pushes back the liquid introduced between the sliding surfaces into the liquid space, which may result in poor lubrication between the sliding surfaces.

[0007] The present invention has been made in view of these problems, and has as its object to provide a sliding component that can prevent poor lubrication between sliding surfaces when the relative rotation speed is low. [Means for solving the problem]

[0008] In order to solve the above problems, the sliding component of the present invention comprises: A sliding component in which a pair of sliding rings rotate relative to each other and partition a first fluid space and a second fluid space, The sliding surfaces of the pair of sliding rings are provided on the first fluid space side and have specific dynamic pressure generating grooves that generate dynamic pressure by the first fluid; a dynamic pressure generating groove that is provided closer to the second fluid space than the specific dynamic pressure generating groove and generates dynamic pressure by the second fluid; a communication groove communicating with the first fluid space; a circumferential groove that is provided closer to the second fluid space than the specific dynamic pressure generating groove and extends in a circumferential direction from the communication groove; The first fluid introduction groove is provided closer to the second fluid space than the circumferential groove and introduces the first fluid. This ensures that the amount of first fluid supplied between the sliding surfaces is sufficient over a wide circumferential range of the circumferential groove at low relative rotational speeds, and also prevents the second fluid from moving toward the first fluid space due to the first fluid supplied between the sliding surfaces from the first fluid inlet groove, thereby preventing poor lubrication between the sliding surfaces at low relative rotational speeds.

[0009] The circumferential groove and the first fluid introduction groove may be in communication with each other. This allows the first fluid to be introduced into the first fluid introduction groove from the circumferential groove.

[0010] The communication groove may extend radially from the first fluid space toward the circumferential groove. This can prevent the first fluid from being excessively introduced from the first fluid space into the communication groove and the circumferential groove when the pair of sliding rings rotate relative to each other.

[0011] The communication groove may extend from the first fluid space toward the circumferential groove at an angle in the rotational direction. This makes it easier to smoothly introduce the first fluid from the first fluid space into the communication groove and the circumferential groove when the pair of sliding rings rotate relative to each other.

[0012] An annular groove may be formed between the first fluid introduction groove and the dynamic pressure generating groove. According to this, the first fluid and the second fluid move along the annular groove, and therefore the interface between the first fluid and the second fluid can be stabilized.

[0013] The circumferential groove may be annular. This ensures an adequate amount of the first fluid to be supplied between the sliding surfaces from the circumferential groove, and also prevents the second fluid from moving toward the first fluid space side of the circumferential groove.

[0014] The first fluid introduction groove may be a spiral groove. This allows dynamic pressure to be generated at the closed end of the first fluid introduction groove.Furthermore, the first fluid introduction grooves can be provided close to each other in the circumferential direction, which increases the degree of freedom in design.

[0015] The dynamic pressure generating groove may be a spiral groove, and the closed end of the dynamic pressure generating groove may face the closed end of the first fluid introduction groove. This effectively prevents the second fluid from moving toward the first fluid space due to dynamic pressure generated at the closed end of the first fluid introduction groove.

[0016] The first fluid may be a liquid and the second fluid may be a gas. This allows liquid lubrication when the relative rotation speed is low, and gas lubrication when the relative rotation speed is high. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a vertical cross-sectional view showing an example of a mechanical seal according to a first embodiment of the present invention. [Figure 2] 3 is a view of the sliding surface of the stationary seal ring in the first embodiment as viewed from the axial direction. FIG. [Figure 3] 1 is an enlarged view of the sliding surface of the stationary seal ring in Example 1 as viewed from the axial direction, and is also a view for schematically explaining the operation at low relative rotation speeds. [Figure 4] FIG. 10 is an enlarged view of the sliding surface of the stationary seal ring in the second embodiment of the present invention, as viewed from the axial direction. [Figure 5] FIG. 10 is a view of the sliding surface of a stationary seal ring according to a third embodiment of the present invention, as viewed from the axial direction. [Figure 6] FIG. 10 is an enlarged view of the sliding surface of the stationary seal ring according to the fourth embodiment of the present invention, as viewed from the axial direction. [Figure 7] FIG. 10 is an enlarged view of the sliding surface of the stationary seal ring according to the fifth embodiment of the present invention, as viewed from the axial direction. [Figure 8] FIG. 13 is an enlarged view of the sliding surface of the stationary seal ring according to the sixth embodiment of the present invention, as viewed from the axial direction. [Figure 9] FIG. 13 is an enlarged view of the sliding surface of the stationary seal ring according to the seventh embodiment of the present invention, as viewed from the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sliding element according to an embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0019] A sliding component according to a first embodiment will be described with reference to Fig. 1 to Fig. 3. In this embodiment, a liquid F serving as a sealed fluid is present in an outer space S1 serving as a first fluid space of the mechanical seal, and a gas A is present in an inner space S2 serving as a second fluid space. That is, in this embodiment, the first fluid is the liquid F, and the second fluid is the gas A. For ease of explanation, grooves formed on the sliding surface may be indicated by dots in the drawings.

[0020] The mechanical seal shown in FIG. 1 is an inside type that seals the liquid F in the outer space S1 that tends to leak from the outer diameter side to the inner diameter side of the sliding surface, and the inner space S2 communicates with the gas A.

[0021] The mechanical seal is mainly composed of a rotary seal ring 20 as the other sliding ring and a stationary seal ring 10 as one sliding ring. The rotary seal ring 20 is annular and is attached to the rotating shaft 1 using a sleeve 2 so that it can rotate together with the rotating shaft 1.

[0022] The stationary seal ring 10 is annular and is mounted on a seal cover 5 fixed to a housing 4 of the device to which it is attached in a non-rotating state but movable in the axial direction. The static seal ring 10 is axially biased by an elastic member 7, so that the sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotating seal ring 20 slide closely against each other. The sliding surface 21 of the rotating seal ring 20 is flat, and this flat surface does not have any recesses such as grooves.

[0023] The stationary seal ring 10 and the rotating seal ring 20 are typically formed from a combination of SiC (hard material) or SiC (hard material) and carbon (soft material), but any sliding material used for mechanical seals can be used. Examples of SiC include sintered bodies using boron, aluminum, carbon, or other sintering aids, as well as materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC consisting of SiC and Si, SiC-TiC, and SiC-TiN. Examples of carbon include a mixture of carbonaceous and graphite materials, resin-molded carbon, and sintered carbon. In addition to the above sliding materials, metal materials, resin materials, surface-modified materials (coating materials), and composite materials can also be used.

[0024] As shown in FIGS. 2 and 3, the rotary seal ring 20 slides relative to the stationary seal ring 10 in the clockwise direction as indicated by the solid arrow.

[0025] The sliding surface 11 of the stationary seal ring 10 is provided with a plurality of deep grooves 13 (four in this embodiment), a plurality of liquid introduction grooves 14 (60 in this embodiment) as first fluid introduction grooves, a plurality of dynamic pressure generating grooves 15 (60 in this embodiment), and Rayleigh steps 16 (four in this embodiment) as specific dynamic pressure generating grooves.

[0026] Furthermore, the portion of the sliding surface 11 other than the deep grooves 13, the liquid introduction grooves 14, and the dynamic pressure generating grooves 15 is a flat surface arranged on the same plane as the land 12. The flat surface of the land 12 functions as a sliding surface that essentially slides against the sliding surface 21 of the rotating seal ring 20.

[0027] The deep groove 13 has a communicating groove portion 131 as a communicating groove and a circumferential groove portion 132 as a circumferential groove, and is generally T-shaped when viewed in the axial direction. The communicating groove portion 131 communicates with the outer space S1 and extends from the outer edge of the sliding surface 11 in the radially inward direction.

[0028] The circumferential grooves 132 extend concentrically with the sliding surface 11 from the inner diameter end of the communicating groove 131 on both sides in the circumferential direction. The communicating grooves 131 and the circumferential grooves 132 have the same depth.

[0029] The circumferential length L1 of each circumferential groove 132 is greater than the circumferential length L2 of the communicating groove 131 (L1>L2).

[0030] The liquid introduction groove 14 is provided on the inner diameter side of the circumferential groove portion 132, separated therefrom via the land 12a, and is not connected to the circumferential groove portion 132. The liquid introduction groove 14 extends in an arc shape while slanting with a counterclockwise component from the outer diameter side toward the inner diameter side. In other words, the liquid introduction groove 14 is a spiral groove.

[0031] The liquid introduction groove 14 is formed to a constant depth in the circumferential direction. The depth of this liquid introduction groove 14 is shallower than the depth of the deep groove 13. Note that the liquid introduction groove 14 is not limited to extending in an inclined arc shape, but may also extend linearly, as long as it has the function of introducing liquid into the inner diameter side. Furthermore, the liquid introduction groove 14 of this embodiment introduces liquid into the inner diameter side and generates positive pressure at the closed end 14A.

[0032] The dynamic pressure generating groove 15 communicates with the internal space S2. The dynamic pressure generating groove 15 extends in an arc shape with an inclination having a counterclockwise component from the outer diameter side toward the inner diameter side. In other words, the dynamic pressure generating groove 15 is a spiral groove. The dynamic pressure generating groove 15 may not communicate with the internal space S2.

[0033] The dynamic pressure generating grooves 15 extend in an arc shape in the circumferential direction while inclining with a counterclockwise component from the inner diameter side toward the outer diameter side, and are formed to a constant depth. The depth of these dynamic pressure generating grooves 15 is shallower than the depth of the deep grooves 13. Note that the dynamic pressure generating grooves 15 are not limited to those extending in an arc shape while inclining, and may extend linearly as long as they have the function of guiding gas to the outer diameter side and generating positive pressure at the closed end portions 15A.

[0034] A closed end 14A on the inner diameter side of the liquid introduction groove 14 and a closed end 15A on the outer diameter side of the dynamic pressure generation groove 15 are spaced apart in the radial direction by the land 12c and face each other.

[0035] The Rayleigh step 16 extends counterclockwise from the communicating groove portion 131 concentrically with the sliding surface 11, and is disposed on the outer diameter side of the annular circumferential groove portion 132. The Rayleigh step 16 is shallower than the deep groove 13, and has a constant depth in the circumferential direction. Note that the Rayleigh step 16 may not be connected to the communicating groove portion 131.

[0036] Next, the operation of the stationary seal ring 10 and the rotary seal ring 20 during relative rotation will be described with reference to Figure 3. In Figure 3, the flow of liquid F is shown by white arrows, and the flow of gas A is shown by black arrows.

[0037] First, when the rotary seal ring 20 is not rotating and is at rest, liquid F flows into the deep groove 13, liquid introduction groove 14, and Rayleigh step 16, which are provided closer to the outer space S1 than the land 12c. Also, gas A flows into the dynamic pressure generating groove 15, which is provided closer to the inner space S2 than the land 12c.

[0038] Furthermore, when not rotating, the stationary seal ring 10 is biased toward the rotating seal ring 20 by the elastic member 7, so the sliding surfaces 11, 21 are in contact with each other, and almost no liquid F leaks out between the sliding surfaces 11, 21 into the internal space S2.

[0039] As shown in FIG. 3, during low-speed rotation when the rotating seal ring 20 begins to rotate relative to the stationary seal ring 10, the liquid F in the deep grooves 13, liquid introduction grooves 14, and Rayleigh steps 16, mainly the surface layer of the liquid F, moves in the rotational direction of the rotating seal ring 20 due to shear with the sliding surface 21.

[0040] As a result, the liquid F in the circumferential groove portion 132 moves from the end portion 132A (see FIG. 2) on the upstream side of the relative rotation toward the end portion 132B on the downstream side of the relative rotation, as shown by the arrow D2.

[0041] The liquid F that has moved toward the end 132B of the circumferential groove portion 132 flows out from the end 132B and its vicinity between the sliding surfaces 11 and 21, as shown by arrow D3. The deep groove 13 is deep enough so that no positive pressure is generated at the end 132B and its vicinity.

[0042] Furthermore, as shown by arrow D1, the liquid F in the outer space S1 is drawn into the circumferential groove portion 132 and the Rayleigh step 16 through the communicating groove portion 131.

[0043] Furthermore, as shown by arrow D8, the liquid F inside the Rayleigh step 16 moves toward the closed end 16A of the Rayleigh step 16. As shown by arrow D9, the liquid F that has moved toward the closed end 16A of the Rayleigh step 16 generates positive pressure at and near the closed end 16A.

[0044] Furthermore, the liquid F in the liquid inlet groove 14 moves from the closed end 14B on the outer diameter side toward the closed end 14A on the inner diameter side, as shown by arrow D4. The liquid F between the sliding surfaces 11 and 21 is drawn into the liquid inlet groove 14 from the periphery of the closed end 14B.

[0045] The liquid F that has moved toward the closed end 14A of the liquid introduction groove 14 flows out from the closed end 14A and its vicinity into between the sliding surfaces 11 and 21, as shown by arrow D5.

[0046] Furthermore, the pressure of the liquid F in the liquid inlet groove 14 is increased at the closed end 14A and its vicinity. That is, a positive pressure is generated at the closed end 14A of the liquid inlet groove 14 and its vicinity.

[0047] The positive pressure generated at and near the closed end 14A of the liquid introduction groove 14 and the positive pressure generated at and near the closed end 16A of the Rayleigh step 16 cause a slight separation between the sliding surfaces 11 and 21, causing liquid F to flow between the sliding surfaces 11 and 21 from the outer space S1 as shown by arrow D10, and gas A to flow between the sliding surfaces 11 and 21 from the inner space S2 as shown by arrow D11.

[0048] On the other hand, gas A in the dynamic pressure generating groove 15 moves from the inner diameter side closed end 15B toward the inner diameter side closed end 15A as shown by arrow D6. Note that gas A between the sliding surfaces 11 and 21 is drawn into the dynamic pressure generating groove 15 from the periphery of the closed end 15B.

[0049] The gas A that has moved toward the closed end 15A of the dynamic pressure generating groove 15 flows out from the vicinity of the closed end 15A to between the sliding surfaces 11 and 21, as shown by arrow D7.

[0050] Furthermore, when the relative rotation speed between the rotating seal ring 20 and the stationary seal ring 10 is low, the gas A does not become sufficiently dense within the dynamic pressure generating groove 15, so high positive pressure is not generated, and almost no force acts to separate the sliding surfaces 11, 21.

[0051] Gas A that flows out from the closed end 15A and its vicinity between the sliding surfaces 11 and 21 is guided to move toward the outer diameter side, but is pushed back toward the inner diameter side by the positive pressure generated at the closed end 14A of the liquid introduction groove 14 and its vicinity.

[0052] Furthermore, although not shown, when the relative rotational speed of the rotating seal ring 20 increases, a large amount of gas A moves from the closed end 15B of the dynamic pressure generating groove 15 toward the closed end 15A, increasing the pressure at and near the closed end 15A. In other words, a positive pressure is generated at and near the closed end 15A of the dynamic pressure generating groove 15.

[0053] At this time, the positive pressure generated at and near the closed end 15A of the dynamic pressure generating groove 15 becomes greater than the positive pressure generated at and near the closed end 14A of the liquid introduction groove 14, and the sliding surfaces 11 and 21 become further apart than when the relative rotation speed is low.

[0054] During high-speed rotation, the mechanical seal of this embodiment separates the sliding surfaces 11, 21 to such an extent that the liquid F in the deep groove 13 and the liquid introduction groove 14 hardly acts on the sliding surface 21. Consequently, gas lubrication by the gas A is ultimately achieved between the sliding surfaces 11, 21.

[0055] As explained above, when the relative rotation speed between the stationary seal ring 10 and the rotating seal ring 20 is low, the amount of liquid F supplied between the sliding surfaces 11, 21 can be ensured over a wide circumferential range of the circumferential groove portion 132 of the deep groove 13. In addition, the liquid F supplied between the sliding surfaces 11, 21 from the liquid introduction groove 14 pushes back the gas A supplied between the sliding surfaces 11, 21 from the internal space S2 or the closed end 15A of the dynamic pressure generating groove 15 in the radially inward direction.

[0056] For example, normally, the pressure of the liquid F in the outer space S1 is higher than the pressure of the gas A in the inner space S2, but there are cases where the pressure of the gas A becomes higher than the pressure of the liquid F. Even in such a case, the liquid introduction groove 14 is provided at a distance on the outer diameter side from the closed end 15A of the dynamic pressure generating groove 15, and this liquid introduction groove 14 draws in the liquid F from the outer diameter side, thereby preventing the gas A from pushing out the liquid F from between the sliding surfaces 11, 21. This makes it possible to prevent poor lubrication between the sliding surfaces 11, 21 when the relative rotation speed is low.

[0057] Furthermore, the communicating groove portion 131 extends radially from the outer space S1 toward the circumferential groove portion 132. This makes it possible to suppress excessive introduction of the liquid F from the outer space S1 into the deep groove 13 when the stationary seal ring 10 and the rotating seal ring 20 are rotating at high relative rotational speeds, thereby preventing gas lubrication from being hindered.

[0058] Furthermore, because the liquid inlet groove 14 is a spiral groove, dynamic pressure can be generated at the closed end 14A of the liquid inlet groove 14. Therefore, even if the gas A has a higher pressure than the liquid F, the gas A can be effectively pushed back toward the inner diameter side.

[0059] Furthermore, the liquid introduction grooves 14 can be provided close to each other in the circumferential direction, allowing for a high degree of freedom in design.

[0060] Furthermore, the dynamic pressure generating groove 15 is a spiral groove, and the closed end 15A of the dynamic pressure generating groove 15 faces the closed end 14A of the liquid introduction groove 14. This effectively prevents the gas A from moving toward the external space S1 due to the positive pressure generated at the closed end 14A of the liquid introduction groove 14.

[0061] Furthermore, liquid lubrication can be achieved by the liquid F when the relative rotation speed is low, and gas lubrication can be achieved by the gas A when the relative rotation speed is high.

[0062] In this embodiment, the deep groove 13 is exemplified as having a substantially T-shape in the axial direction formed by the communicating groove portion 131 and the circumferential groove portion 132, but the circumferential groove may be formed in an L-shape in the axial direction, with the circumferential groove extending from the inner diameter end of the communicating groove to one side in the circumferential direction. Also, the communicating groove portion may extend more inward than the circumferential groove portion.

[0063] Furthermore, the circumferential groove 132 is not limited to extending in an arc shape, but may extend linearly.

[0064] Furthermore, in this embodiment, the liquid introduction groove 14 and the dynamic pressure generating groove 15 are spiral grooves that are inclined with radial and circumferential components, but this is not limited to this, and they may be dimples that are rectangular or circular when viewed in the axial direction, or Rayleigh steps that extend circumferentially, etc.

[0065] Furthermore, the liquid introduction groove 14 may be a deep groove that does not generate positive pressure.

[0066] Furthermore, in this embodiment, the closed end 14A of the liquid introduction groove 14 and the closed end 15A of the dynamic pressure generating groove 15 are exemplified as being arranged radially spaced apart and facing each other along a radial line, but the closed ends of the liquid introduction groove and the dynamic pressure generating groove do not have to be on a meridian as long as they are spaced apart radially. [Example]

[0067] Next, a sliding element according to a second embodiment will be described with reference to Fig. 4. Note that a description of the same configuration as in the first embodiment will be omitted.

[0068] 4, in the stationary seal ring 200 of this second embodiment, the outer diameter end of the liquid introduction groove 24 communicates with the circumferential groove portion 232 of the deep groove 23. This allows a large amount of liquid F to be introduced into the liquid introduction groove 24 from the circumferential groove portion 232 of the deep groove 23, so that liquid F can be reliably supplied between the sliding surfaces at low relative rotational speeds, enabling liquid lubrication. Furthermore, even if gas A has a higher pressure than liquid F, gas A can be reliably pushed back toward the inner diameter side.

[0069] Furthermore, the inner diameter ends of the dynamic pressure generating grooves 25 communicate with the internal space S2. This allows gas A to be supplied from the internal space S2 to the dynamic pressure generating grooves 25, so that positive pressure is reliably generated at high relative rotation speeds, the sliding surfaces can be separated, and gas lubrication can be achieved. [Example]

[0070] Next, a sliding element according to a third embodiment will be described with reference to Fig. 5. Note that a description of the same configuration as in the second embodiment will be omitted.

[0071] 5, in the stationary seal ring 300 of the third embodiment, the circumferential groove portion 332 of the deep groove 33 has an annular shape.

[0072] In this way, since the circumferential groove portion 332 has an annular shape, the liquid F can be supplied between the sliding surfaces around the entire circumference of the sliding surface 310 when the relative rotation speed is low, and the amount of liquid F supplied between the sliding surfaces can be ensured.

[0073] Furthermore, even if gas A moves beyond the liquid introduction groove 34 toward the outer diameter side during low relative rotation speeds, the gas A is recovered in the circumferential groove portion 332, so that the liquid F can be maintained on the outer diameter side of the circumferential groove portion 332 between the sliding surfaces.

[0074] Furthermore, in the third embodiment, the form in which four communication grooves 331 communicate with the annular circumferential groove 332 has been exemplified, but the communication grooves communicating with the annular circumferential groove can be freely changed. For example, it is sufficient that one or more communication grooves communicate with the annular circumferential groove.

Embodiment

[0075] Next, the sliding component according to the fourth embodiment will be described with reference to FIG. 6. In addition, the description of the same configuration as that of the third embodiment will be omitted.

[0076] As shown in FIG. 6, in the stationary seal ring 400 of the fourth embodiment, an annular groove 47 is formed between the liquid introduction groove 44 and the dynamic pressure generation groove 45. According to this, the liquid F introduced from the liquid introduction groove 44 between the sliding surfaces and the gas A introduced from the dynamic pressure generation groove 45 between the sliding surfaces move along the annular groove 47, so that the interface between the liquid F and the gas A can be stabilized.

[0077] Furthermore, the groove provided between the liquid introduction groove 44 and the dynamic pressure generation groove 45 is not limited to the annular groove 47, and may be a substantially C-shaped or arc-shaped groove. Furthermore, a plurality of concentric grooves may be provided.

Embodiment

[0078] Next, the sliding component according to the fifth embodiment will be described with reference to FIG. 7. In addition, the description of the same configuration as that of the fourth embodiment will be omitted.

[0079] As shown in FIG. 7, in the stationary seal ring 500 of the fifth embodiment, the circumferential length L10 of the circumferential groove portion 532 in the deep groove 53 is smaller than the circumferential length L20 of the communication groove portion 531 (L10 < L20). In other words, a large area of the deep groove 53 is secured. According to this, the amount of the liquid F supplied from the deep groove 53 to between the sliding surfaces or the liquid introduction groove 54 can be ensured at the time of relatively low rotational speed.

Embodiment

[0080] Next, a sliding element according to a sixth embodiment will be described with reference to Fig. 8. Note that a description of the same configuration as in the fifth embodiment will be omitted.

[0081] 8, in the stationary seal ring 600 of this fifth embodiment, the communicating groove portion 631 of the deep groove 63 extends from the outer space S1 in the radially inward direction while inclining counterclockwise. This allows liquid to be smoothly introduced from the outer space S1 toward the circumferential groove portion 632 when the relative rotation speed is low.

[0082] Furthermore, the stationary seal ring 600 is provided with a spiral groove 640 as a specific dynamic pressure generating groove. This spiral groove 640 extends approximately parallel to the communicating groove portion 631. As a result, the spiral groove 640 allows the liquid F in the outer space S1 to be introduced to the inner diameter side, so that a large amount of liquid F can be secured between the sliding surfaces, thereby improving slidability. [Example]

[0083] Next, a sliding element according to a seventh embodiment will be described with reference to Fig. 9. Note that a description of the same configuration as in the second embodiment will be omitted.

[0084] 9, in the mechanical seal of the seventh embodiment, a liquid F exists in the inner space S2 and a gas A exists in the outer space S1. In the stationary seal ring 700, the communicating groove portion 731 of the deep groove 73 communicates with the inner space S2.

[0085] The liquid introduction groove 74 extends in an arc shape from the circumferential groove portion 732 of the deep groove 73 to the outer diameter side while being inclined with a counterclockwise component.

[0086] The dynamic pressure generating groove 75 extends in an arc shape while tilting counterclockwise from the outer diameter side to the inner diameter side. The outer diameter end of this dynamic pressure generating groove 75 communicates with the outer space S1.

[0087] The Rayleigh step 76 extends counterclockwise from the communicating groove 731 concentrically with the sliding surface.

[0088] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0089] For example, in the first to seventh embodiments, a mechanical seal was used as an example of the sliding component, but the sliding component may be a shaft sealing component other than a mechanical seal.Furthermore, the sliding component may be a component other than a shaft sealing component, such as a bearing component.

[0090] Furthermore, in the above-described Examples 1 to 7, examples were described in which the deep grooves, liquid introduction grooves, and dynamic pressure generating grooves were provided on the stationary seal ring, but each groove may also be provided on the rotary seal ring. In other words, one of the sliding rings of the present invention may be either a static seal ring or a rotary seal ring. Furthermore, these grooves may be provided on both the stationary seal ring and the rotary seal ring. Furthermore, it is sufficient that the sliding surfaces of the pair of sliding rings are provided with these grooves. For example, the sliding surface of one sliding ring may be provided with the deep grooves and liquid introduction grooves, and the sliding surface of the other sliding ring may be provided with the dynamic pressure generating grooves.

[0091] Furthermore, in Examples 1 to 7, a configuration was exemplified in which liquid F was present in one of the outer space and the inner space and gas A was present in the other, but liquid F may be present in both spaces, or gas A may be present in both spaces.

[0092] In addition, in the above-mentioned Examples 1 to 7, the gas A may be in the form of a mist in which a liquid and a gas are mixed.

[0093] Furthermore, in Examples 1 to 7, the bottom surfaces of the deep grooves, liquid introduction grooves, and dynamic pressure generating grooves extend parallel to the flat surface of the land, but this is not limited to this. For example, the bottom surface of each groove may be inclined so that it becomes shallower toward the downstream side of the relative rotation.

[0094] In the above-described Examples 4 to 6, the specific dynamic pressure generating grooves communicate with the liquid space, but they may not communicate with the liquid space. Furthermore, the specific dynamic pressure generating grooves are not limited to Rayleigh step grooves or spiral grooves and may be freely changed. [Explanation of symbols]

[0095] 1 Rotation axis 2 sleeves 4. Housing 10 Stationary seal ring (one of the sliding rings) 11 Sliding surface 12c Land 13 deep groove 14 Liquid introduction groove 14A Closed end 15 Dynamic pressure generating groove 15A closed end 16 Rayleigh Step (specific dynamic pressure generating groove) 20 Rotating seal ring 21 Sliding surface 23 deep groove 24 Liquid introduction groove 25 Dynamic pressure generating groove 33 deep groove 34 Liquid introduction groove 43 deep groove 44 Liquid introduction groove 53 deep groove 63 deep groove 73 deep groove 74 Liquid introduction groove 75 Dynamic pressure generating groove 131 Communication groove (communication groove) 132 Circumferential groove (circumferential groove) 200~700 Stationary sealing ring 640 Spiral groove (specific dynamic pressure generating groove) A Gas (second fluid) F liquid (first fluid) S1 outside space (first fluid space) S2 Inner space (second fluid space)

Claims

1. A sliding component including a pair of sliding rings that rotate relative to each other and that partition a first fluid space and a second fluid space, The sliding surfaces of the pair of sliding rings are provided on the first fluid space side and have specific dynamic pressure generating grooves that generate dynamic pressure by the first fluid; a dynamic pressure generating groove that is provided closer to the second fluid space than the specific dynamic pressure generating groove and generates dynamic pressure by the second fluid; a communication groove communicating with the first fluid space; a circumferential groove that is provided closer to the second fluid space than the specific dynamic pressure generating groove and extends in a circumferential direction from the communication groove; a first fluid introduction groove that is provided closer to the second fluid space than the circumferential groove and that introduces the first fluid.

2. The sliding component according to claim 1 , wherein the circumferential groove and the first fluid introduction groove are in communication with each other.

3. The sliding element according to claim 1 , wherein the communication groove extends in a radial direction from the first fluid space toward the circumferential groove.

4. The sliding element according to claim 1 , wherein the communication groove extends from the first fluid space toward the circumferential groove at an angle in the rotational direction.

5. 2. The sliding component according to claim 1, wherein an annular groove is formed between the first fluid introduction groove and the hydrodynamic pressure generating groove.

6. 2. The sliding element according to claim 1, wherein the circumferential groove is annular.

7. 2. The sliding component according to claim 1, wherein the first fluid introduction groove is a spiral groove.

8. 8. A sliding component according to claim 7, wherein the dynamic pressure generating groove is a spiral groove, and a closed end of the dynamic pressure generating groove faces a closed end of the first fluid introduction groove.

9. 9. The sliding element according to claim 1, wherein the first fluid is a liquid and the second fluid is a gas.

Images