Sliding parts

Abstract

Provided is a sliding component which enables a fluid to easily flow into a spiral groove.　This sliding component comprises a pair of sliding rings 10, 20 that mutually slide relatively to each other, and has provided in a sliding surface 11 of one sliding ring 10 a spiral groove 13 which is contiguous to a space S1 of a leakage side. At the edge of the one sliding ring 10 on the one space S1 side, an expansion part 17 is formed in a manner as to expand toward the one space S1 contiguous from the sliding surface 11 of the one sliding ring 10. An inclined groove 61 that is contiguous to the spiral groove 13 and that extends toward the one space is provided to the expansion part 17.

Description

[Technical Field]

[0001] The present invention relates to a sliding component used in a shaft seal or bearing of a rotary machine. [Background technology]

[0002] Mechanical seals, consisting of a pair of annular sliding rings that rotate relative to one another and whose sliding surfaces slide against each other, are known as sliding components for preventing leakage of sealed fluids around the rotating shaft of rotary machines. In recent years, there has been a demand for reducing the energy lost due to sliding, for environmental reasons, and some mechanical seals have been provided with a positive pressure generating groove on the sliding surface of the sliding ring that communicates with the sealed liquid side and has one end closed on the sliding surface.

[0003] For example, the mechanical seal shown in Patent Document 1 has a plurality of spiral grooves, which are positive pressure generating grooves that communicate with the leakage side but not with the sealed liquid side, arranged circumferentially via lands on the sliding surface of one of the sliding rings. According to this, during relative rotation of the sliding rings, the leakage fluid is introduced into the spiral grooves, and the leakage fluid concentrates on the wall of the end of the spiral groove in the relative rotation direction, generating positive pressure, separating the sliding surfaces, and forming a fluid film of the leakage fluid on the sliding surfaces, improving lubrication and achieving low friction. Furthermore, the leakage fluid acts to push the sealed fluid near the end of the spiral groove in the relative rotation direction back toward the sealed fluid, thereby reducing the amount of sealed fluid leaking to the leakage side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 62-31775 (page 2, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0005] In the mechanical seal of Patent Document 1, the leakage fluid in the spiral groove moves toward the end in the relative rotation direction in response to the relative rotation of the pair of sliding rings, thereby continuously supplying the leakage fluid from the leakage space into the spiral groove. However, in a mechanical seal such as that of Patent Document 1, the corner formed by the bottom surface of the spiral groove and the leakage side circumferential surface of the sliding ring is formed at a right angle, so that when the leakage fluid is introduced from the leakage space into the spiral groove, a vortex is likely to occur near this corner, preventing the leakage fluid from being effectively introduced into the spiral groove, and there is a risk of the leakage fluid in the spiral groove decreasing.

[0006] The present invention has been made in view of these problems, and has as its object to provide a sliding component in which a fluid can be easily introduced into a spiral groove. [Means for solving the problem]

[0007] In order to solve the above problems, the sliding component of the present invention comprises: A pair of sliding rings that slide relative to each other are provided, a sliding component in which a spiral groove communicating with at least one of a space on the sealed fluid side and a space on the leakage side is provided on the sliding surface of the one sliding ring, an expanded portion is formed on an edge portion of the one sliding ring on the side of the one space, the expanded portion being continuous with a sliding surface of the one sliding ring and expanding toward the one space, The expanding portion is provided with an inclined groove that is continuous with the spiral groove and extends toward the one space. With this, the fluid moves smoothly from one space into the spiral groove along the bottom surface of the inclined groove that widens towards one space, making it easier for the fluid to be introduced into the spiral groove.

[0008] The inclined groove may extend to a peripheral surface of the one sliding ring on the side of the one space. This allows fluid to be easily introduced into the inclined groove from the radial direction.

[0009] The bottom surface of the spiral groove and the bottom surface of the inclined groove may form an obtuse angle. This makes it difficult for vortices to occur at the boundary between the bottom surface of the spiral groove and the bottom surface of the inclined groove.

[0010] The inclined groove may be formed by an inclined bottom surface that is continuous with the bottom surface of the spiral groove, and side surfaces that rise from both circumferential edge portions of the inclined bottom surface. This allows the fluid to be easily introduced into the spiral groove from the inclined groove.

[0011] The inclined groove may be formed to a constant depth. This allows the fluid introduced into the inclined groove to move smoothly along the bottom surface of the inclined groove.

[0012] The inclined groove may be formed to the same depth as the spiral groove. This allows the fluid to be easily introduced into the spiral groove from the inclined groove.

[0013] The sliding surface of the one sliding ring may be provided with a reverse spiral groove that is provided on the other space side of the spiral groove, extends in a direction opposite to the spiral groove, and generates dynamic pressure. With this, during reverse rotation, the fluid on the other space side that has entered the reverse spiral groove on the other space side of the spiral groove follows due to shear with the sliding surface of one of the slide rings and is returned between the sliding surfaces from the end of the reverse spiral groove on the other space side toward the other space side. This makes it possible to increase lubrication during reverse rotation as well as forward rotation, and to reduce leakage of the fluid on the other space side into one space side during reverse rotation.

[0014] In this specification, a spiral groove is defined as a groove extending in a direction that has both radial and circumferential components. Similarly, a reverse spiral groove is defined as a groove extending in a direction that has both radial and circumferential components, and whose circumferential direction extending from upstream to downstream during relative rotation is opposite to that of a spiral groove. [Brief explanation of the drawings]

[0015] [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] 3 is an enlarged view of the sliding surface of the stationary seal ring in the first embodiment as viewed from the axial direction. FIG. [Figure 4] 4(a) is a cross-sectional view taken along the line AA in FIG. 3, and FIG. 4(b) is a view of the spiral groove and the inclined groove as seen from the inner diameter side. [Figure 5] FIG. 10 is a cross-sectional view of a spiral groove and an inclined groove in Example 2 of the present invention. [Figure 6] 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 7] FIG. 10 is a view of the sliding surface of a stationary seal ring according to a fourth embodiment of the present invention, as viewed from the axial direction. [Figure 8] FIG. 10 is a 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 9] FIG. 13 is a view of the sliding surface of a stationary seal ring according to a sixth embodiment of the present invention, as viewed from the axial direction. [Figure 10] FIG. 13 is a 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. [Figure 11] FIG. 13 is a view of the sliding surface of the stationary seal ring according to the eighth embodiment of the present invention, as viewed from the axial direction. [Figure 12] FIG. 13 is a view of the sliding surface of the stationary seal ring according to the ninth embodiment of the present invention, as viewed from the axial direction. [Figure 13] FIG. 23 is a view of the sliding surface of the stationary seal ring according to the tenth embodiment of the present invention, as viewed from the axial direction. [Figure 14] FIG. 23 is a view of the sliding surface of the stationary seal ring according to the eleventh embodiment of the present invention, as viewed from the axial direction. [Figure 15] FIG. 23 is a view of the sliding surface of the stationary seal ring according to the twelfth embodiment of the present invention, as viewed from the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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]

[0017] A mechanical seal as a sliding component according to a first embodiment will be described with reference to Figures 1 to 4. In this embodiment, the atmosphere A is present in the inner space S1 of the mechanical seal, and the sealed fluid F is present in the outer space S2. The inner diameter side of the sliding ring constituting the mechanical seal will be described as the leakage side (low pressure side), and the outer diameter side as the sealed fluid side (high pressure side). For ease of explanation, grooves formed on the sliding surface may be indicated by dots in the drawings.

[0018] 1 is an inside type mechanical seal that seals a sealed fluid F in an outer space S2 that tends to leak from the outer diameter side toward the inner diameter side of the sliding surface, and has an inner space S1 that communicates with the atmosphere A. In this embodiment, the sealed fluid F is a high-pressure liquid, and the atmosphere A is a gas with a lower pressure than the sealed fluid F.

[0019] The mechanical seal is mainly composed of a rotary seal ring 20 as the other sliding ring and a static seal ring 10 as one sliding ring. The rotary seal ring 20 is annular and is mounted on a rotary shaft 1 via a sleeve 2 so that it can rotate together with the rotary shaft 1. The stationary seal ring 10 is annular and is mounted in a seal cover 5 fixed to a housing 4 of the device to which it is attached so that it can move axially but not rotate. 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 rotary seal ring 20 slide closely against each other. The sliding surface 21 of the rotary seal ring 20 is flat and does not have any recesses such as grooves.

[0020] 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.

[0021] As shown in FIGS. 2 and 3, the rotary seal ring 20 slides relative to the stationary seal ring 10 in the counterclockwise direction as indicated by the solid arrow.

[0022] A plurality of spiral grooves 13 are provided on the sliding surface 11 of the stationary seal ring 10. The spiral grooves 13 are arranged evenly in the circumferential direction on the inner diameter side of the sliding surface 11 (24 grooves in this embodiment).

[0023] The portion of the sliding surface 11 other than the spiral groove 13 is a flat land 12 arranged on the same plane. The flat surface of the land 12 functions as a sliding surface that substantially slides against the sliding surface 21 of the rotary seal ring 20.

[0024] Furthermore, the edge portion of the stationary seal ring 10 on the inner space S1 side forms an expansion portion 17 that expands toward the inner space S1, and has a so-called chamfered shape. The expansion portion 17 has a plurality of inclined grooves 61 and an expansion surface 17a. In other words, a plurality of inclined grooves 61 and an expansion surface 17a are provided on the edge portion of the stationary seal ring 10 that is on the inner diameter side of the sliding surface 11. The expansion surfaces 17a are continuous with the sliding surface 11 and are arranged between circumferentially adjacent inclined grooves 61 at the edge portion on the inner diameter side of the sliding surface 11 (24 expansion surfaces in this embodiment). Furthermore, the inclined grooves 61 extend continuously with the spiral groove 13.

[0025] The expansion surface 17a is a tapered surface that gradually deepens from the flat surface of the land 12 toward one space side, that is, toward the inner peripheral surface 10g of the stationary seal ring 10, which is the peripheral surface on the inner space S1 side in this embodiment (see FIG. 4(a)). The expansion surface 17a may have irregularities, but is preferably a flat surface.

[0026] 3, the spiral groove 13 extends in an arc shape while tilting counterclockwise from the inner diameter side to the outer diameter side. The spiral groove 13 communicates with the inner space S1 but does not communicate with the outer space S2.

[0027] As shown in FIGS. 3 and 4, the spiral groove 13 is composed of a bottom surface 13a, side surfaces 13b and 13c, and an outer diameter side end surface 13d. The bottom surface 13a extends radially parallel to the flat surface of the land 12. That is, the spiral groove 13 is formed to a constant depth D1 (see FIG. 4(a)) in the extension direction. The side surfaces 13b and 13c rise from both circumferential edge portions of the bottom surface 13a. The outer diameter side end surface 13d rises from the outer diameter end of the bottom surface 13a and is connected to the outer diameter ends of the side surfaces 13b and 13c, respectively. An opening 13A communicating with the internal space S1 is formed on the inner diameter side of the spiral groove 13. The spiral groove 13 is formed so that its width increases from the inner diameter side opening 13A toward the outer diameter side end surface 13d.

[0028] The spiral groove 13 is continuous with an inclined groove 61 that extends in the thickness direction of the stationary seal ring 10 and toward the inner space S1. More specifically, an inclined bottom surface 6 that extends toward the inner diameter side is provided continuous with an inner diameter side edge 13g of the bottom surface 13a of the spiral groove 13. More specifically, the inclined bottom surface 6 is the bottom surface of the inclined groove 61, and extends linearly at an incline so that the depth increases from the inner diameter side edge 13g of the bottom surface 13a of the spiral groove 13 toward the inner circumferential surface 10g of the stationary seal ring 10, in other words, so that the distance from the sliding surface 21 of the rotary seal ring 20 increases. The inclined bottom surface 6 is also parallel to the expansion surface 17a.

[0029] The bottom surface 13a of the spiral groove 13 forms an obtuse angle with the inclined bottom surface 6. While this embodiment illustrates an example in which the bottom surface 13a of the spiral groove 13 forms an obtuse angle with the inclined bottom surface 6, the present invention is not limited to this, and the boundary between the bottom surface 13a and the inclined bottom surface 6 may be continuous by a curved surface. Furthermore, a small step may be formed in part near the boundary between the bottom surface 13a and the inclined bottom surface 6.

[0030] That is, the inclined bottom surface 6 widens toward the inner space S1 in a direction away from the rotary seal ring 20, i.e., in the depth direction of the inclined groove 61 (hereinafter, the distance away from the rotary seal ring 20 may be simply referred to as the "depth", and that direction may be referred to as the "depth direction"). The inclined bottom surface 6 may have an uneven or curved surface, but is preferably a flat surface.

[0031] The inclined bottom surface 6 and the expanding surface 17a are connected by side surfaces 6b and 6c rising from both circumferential edges of the inclined bottom surface 6. The side surfaces 6b and 6c are continuous with the side surfaces 13b and 13c of the spiral groove 13 in the radial direction.

[0032] That is, an inclined groove 61 surrounded by the inclined bottom surface 6 and side surfaces 6b, 6c is formed on the edge portion of the stationary seal ring 10 on the inner space S1 side. That is, the inclined groove 61 is continuous with the spiral groove 13 and extends at an incline in the thickness direction toward the inner space S1 side. In other words, the spiral groove 13 is in communication with the inner space S1 through the inclined groove 61.

[0033] The inclined grooves 61 are formed at a constant depth D2 (see FIG. 4(a)) relative to the expanding surface 17a.

[0034] The inclined groove 61 is formed to the same depth as the spiral groove 13 (D1=D2).

[0035] The inclined groove 61 is formed to have the same width as the opening 13A of the spiral groove 13.

[0036] In addition, the circumferentially adjacent inclined grooves 61 communicate with each other through a communication space S11. The communication space S11 is formed between the expansion portion 17 and the inner diameter side end of the rotary seal ring 20 (see FIG. 4(a)).

[0037] Next, the operation of the stationary seal ring 10 and the rotating seal ring 20 during relative rotation will be described with reference to Figures 3 and 4. Note that the flow of atmosphere A in Figure 3 is shown schematically without specifying the relative rotational speed of the rotating seal ring 20.

[0038] First, when the rotary seal ring 20 is not rotating and is at a standstill, the atmosphere A flows into the spiral groove 13. Furthermore, since the static seal ring 10 is biased toward the rotary seal ring 20 by the elastic member 7, the sliding surfaces 11, 21 are in contact with each other, and almost no sealed fluid F leaks out between the sliding surfaces 11, 21 into the internal space S1.

[0039] 3, when the rotary seal ring 20 rotates relative to the stationary seal ring 10, the atmosphere A in the spiral groove 13 moves in the rotational direction of the rotary seal ring 20 due to shear with the sliding surface 21, and the atmosphere A in the inner space S1 is drawn into the spiral groove 13 through the inclined groove 61. In other words, the atmosphere A moves from the inclined groove 61 toward the opening 13A on the inner diameter side of the spiral groove 13, as shown by arrow H1.

[0040] The pressure of the air A moving toward the outer diameter end face 13d of the spiral groove 13 is increased at and near the corner 13B formed by the outer diameter end face 13d and the side face 13c of the spiral groove 13. In other words, a positive pressure is generated at and near the corner 13B of the spiral groove 13.

[0041] Furthermore, the force of the positive pressure generated at and near the corner 13B of the spiral groove 13 (see the white arrow in FIG. 4(a)) causes a slight separation between the sliding surfaces 11 and 21. As a result, air A in the spiral groove 13, as indicated by arrow H2, mainly flows between the sliding surfaces 11 and 21.

[0042] The atmosphere A in the spiral groove 13 indicated by the arrow H2 acts to push the sealed fluid F near the corners 13B on the outer diameter side of the spiral groove 13 back toward the outer space S2, so that little of the sealed fluid F leaks into the spiral groove 13 or the inner space S1. In the mechanical seal of this embodiment, as the relative rotational speed between the stationary seal ring 10 and the rotating seal ring 20 increases, eventually, only the atmosphere A exists between the sliding surfaces 11, 21, i.e., gas lubrication is achieved.

[0043] As shown in FIG. 4( a), the spiral groove 13 is provided on its inner diameter side with a series of inclined grooves 61, each having an inclined bottom surface 6 that inclines so as to widen in the depth direction. This allows air A flowing in the radial direction from a position deeper than the spiral groove 13 to be smoothly supplied to the opening 13A on the inner diameter side of the spiral groove 13 along the inclined bottom surface 6 that constitutes the inclined groove 61. This facilitates introduction of air A into the spiral groove 13, thereby preventing a decrease in the amount of air A within the spiral groove 13. In other words, vortices are less likely to be generated between the bottom surface 13a of the spiral groove 13 and the inclined bottom surface 6. This makes it possible to avoid poor lubrication between the sliding surfaces 11 and 21 during low-speed rotation.

[0044] Furthermore, since the inclined groove 61 extends to the inner circumferential surface 10g of the stationary seal ring 10 and communicates with the inner space S1, the atmosphere A is easily introduced into the inclined groove 61 from the radial direction.

[0045] Furthermore, since the bottom surface 13a of the spiral groove 13 and the inclined bottom surface 6 form an obtuse angle, vortices are less likely to occur at the boundary between the bottom surface 13a and the inclined bottom surface 6, i.e., near the edge 13g, and the air A is smoothly supplied into the spiral groove 13 from the inclined bottom surface 6.

[0046] Furthermore, the inclined grooves 61 are provided continuous with the spiral grooves 13. That is, since the inclined grooves 61 are provided in the stationary seal ring 10 in which the spiral grooves 13 are provided, the state of communication between the inclined grooves 61 and the spiral grooves 13 can always be maintained constant regardless of the relative positions of the stationary seal ring 10 and the rotary seal ring 20 in the circumferential direction or the axial direction.

[0047] Furthermore, multiple inclined grooves 61 are provided spaced apart in the circumferential direction, and adjacent inclined grooves 61 are connected in the circumferential direction by a communication space S11, so that air A can be introduced into the inclined grooves 61 from the radial direction (see arrow H1 in Figure 3) and the circumferential direction (see arrow H3 in Figure 3).

[0048] Furthermore, since the inclined groove 61 is formed at a constant depth D2 (see Figure 4(a)) relative to the expansion surface 17a, the air A introduced into the inclined groove 61 tends to move smoothly along the inclined bottom surface 6, which is the bottom surface of the inclined groove 61.

[0049] Furthermore, since the inclined groove 61 is formed to the same depth as the spiral groove 13 (D1=D2), the fluid can be easily introduced into the spiral groove 13 from the inclined groove 61.

[0050] Furthermore, the expansion surface 17a is formed into an annular shape on the stationary seal ring 10 by grinding or the like, and then the spiral groove 13 and the inclined groove 61 are processed by a laser or the like to form the expansion portion 17, which simplifies the manufacture of the stationary seal ring 10.

[0051] Furthermore, since the inclined groove 61 has side surfaces 6 b and 6 c , the air A introduced into the inclined groove 61 is guided radially toward the spiral groove 13 .

[0052] Furthermore, since the expanding surface 17a does not form an edge on the inner diameter side of the inclined groove 61, it is possible to prevent the end portion on the inner diameter side of the spiral groove 13 from being damaged during relative rotational sliding.

[0053] In this embodiment, the expansion surface 17a extends between the inclined grooves 61 adjacent in the circumferential direction, but the expansion surface may be interrupted midway in the circumferential direction.

[0054] In addition, in this embodiment, the spiral groove has a bottom surface that extends radially parallel to the flat surface of the land, but the bottom surface may be formed as an inclined surface so that the depth of the spiral groove becomes shallower toward the outer or inner end face.

[0055] In addition, in this embodiment, the inclined groove is exemplified as having an inclined bottom surface extending radially parallel to the expansion surface, but the inclined bottom surface may also be formed so that the depth of the inclined groove becomes shallower as it approaches the end face on the outer diameter side or the inner diameter side.

[0056] Furthermore, in this embodiment, the inclined groove and the spiral groove are formed to the same depth, but the inclined groove may be deeper than the spiral groove.

[0057] In addition, in this embodiment, the spiral groove is exemplified as being formed so that its width increases from the opening on the inner diameter side toward the end face on the outer diameter side, but it may also be formed to have the same width from the opening on the inner diameter side to the end face on the outer diameter side, or the end on the outer diameter side may be formed in a tapered shape.

[0058] Furthermore, in this embodiment, the spiral grooves are all formed to the same depth, but for example, shallow spiral grooves for low-speed rotation and deep spiral grooves for high-speed rotation may be arranged alternately in the circumferential direction of the sliding surface.

[0059] Furthermore, the pressure distribution during relative rotation between the stationary seal ring and the rotary seal ring may be optimized by changing the number and width of the spiral grooves provided on the sliding surfaces. [Example]

[0060] Next, a mechanical seal according to a second embodiment will be described with reference to Fig. 5. Note that a description of the same configuration as in the first embodiment will be omitted.

[0061] 5, in the stationary seal ring 210 of the mechanical seal of this embodiment 2, the inclined bottom surface 36 constituting the inclined groove 261 extends radially inward from the radially inner edge of the bottom surface 13a of the spiral groove 13, and unlike in embodiment 1, the inclined bottom surface 36 does not continue to the inner circumferential surface of the stationary seal ring 210. In addition, an end face 36a extending parallel to the flat surface of the land 12 from the radially inner end of the inclined bottom surface 36 further extends radially inward, and the radially inner end of the end face 36a is continuous with the expansion surface 17a.

[0062] Even in this case, the air A is smoothly supplied into the spiral groove 13 along the inclined bottom surface 36 that constitutes the inclined groove 261. [Example]

[0063] Next, a mechanical seal according to a third embodiment will be described with reference to Fig. 6. Note that a description of the same configuration as in the first embodiment will be omitted.

[0064] 6, in the mechanical seal of this third embodiment, a plurality of spiral grooves 13, 315 of different lengths are provided on the sliding surface 311 of the stationary seal ring 310. In detail, the same spiral grooves 13 as in the first embodiment and spiral grooves 315 longer in the extension direction than the spiral grooves 13 are regularly arranged in the circumferential direction on the sliding surface 311. The operation during relative rotation between the stationary seal ring 310 and the rotating seal ring 20 is substantially the same as in the first embodiment except for the change in the length in the extension direction of the spiral grooves 315, and therefore a description thereof will be omitted. [Example]

[0065] Next, a mechanical seal according to a fourth embodiment will be described with reference to Fig. 7. Note that a description of the same configuration as in the first embodiment will be omitted.

[0066] 7, in the mechanical seal of the fourth embodiment, a sliding surface 411 of a stationary seal ring 410 is provided with a plurality of spiral grooves 13, 314, 315 of different lengths. In detail, the sliding surface 411 is regularly arranged in the circumferential direction with the same spiral groove 13 as in the first embodiment, spiral grooves 314 that are shorter in the extension direction than the spiral groove 13, and spiral grooves 315 that are longer in the extension direction than the spiral groove 13. The operation of the stationary seal ring 410 and the rotary seal ring 20 during relative rotation is substantially the same as in the first embodiment except for the change in the extension direction lengths of the spiral grooves 314, 315, and therefore a description thereof will be omitted.

[0067] Although the second embodiment exemplifies a configuration in which two types of spiral grooves 13, 315 and the third embodiment exemplifies a configuration in which three types of spiral grooves 13, 314, 315 are regularly arranged in the circumferential direction, for example, four or more types of spiral grooves may be provided, and the circumferential arrangement of each spiral groove may also be freely changed. It is preferable that the circumferential arrangement of each spiral groove has regularity from the viewpoint of optimizing the pressure distribution during relative rotation between the stationary seal ring and the rotating seal ring. [Example]

[0068] Next, a mechanical seal according to a fifth embodiment will be described with reference to Fig. 8. Note that a description of the same configuration as in the first embodiment will be omitted.

[0069] As shown in FIG. 8 , in the mechanical seal of the fifth embodiment, a sliding surface 511 of a stationary seal ring 510 is provided with a plurality of spiral grooves 513, 515 of different lengths. Specifically, the sliding surface 511 is regularly arranged in the circumferential direction with a spiral groove 513 having the same length in the extension direction as that of the first embodiment and a spiral groove 515 having a longer length in the extension direction than the spiral groove 513. The spiral grooves 513, 515 are each composed of shallow groove portions 513a, 515a and deep groove portions 513b, 515b. That is, the spiral grooves 513, 515 are formed as two-stage stepped grooves with the shallow groove portions 513a, 515a and the deep groove portions 513b, 515b. The shallow groove portions 513a, 515a and the deep groove portions 513b, 515b are each formed to a depth sufficient to generate dynamic pressure.

[0070] The deep groove portions 513b and 515b are formed at the outer diameter side ends of the spiral grooves 513 and 515. The shallow groove portions 513a and 515a extend from the inner diameter side ends of the spiral grooves 513 and 515 along both side surfaces to outer diameter side end faces 513d and 515d.

[0071] This allows the groove portions of the spiral grooves 513, 515 that primarily generate positive pressure to be changed depending on the relative rotational speed between the stationary seal ring 510 and the rotary seal ring 20. At this time, the pressure generated in the deep groove portions 513b, 515b becomes negative relative to the pressure generated in the shallow groove portions 513a, 515a. This promotes the flow of air A introduced into the spiral grooves 513, 515 toward the outer diameter end through the shallow groove portions 513a, 515a and then through the deep groove portions 513b, 515b. Furthermore, the provision of the deep groove portions 513b, 515b makes it difficult for fluid to run out of the spiral grooves 513, 515.

[0072] In this fifth embodiment, the deep groove portions 513b, 515b are formed at the outer diameter side ends of the spiral grooves 513, 515, but the deep groove portions may be formed at the inner diameter side ends of the spiral grooves. Even in this case, the flow of the air A introduced into the spiral grooves toward the outer diameter side ends is promoted, moving in this order through the deep groove portions and then the shallow groove portions.

[0073] Furthermore, in this Example 5, an example was given of a configuration in which the spiral groove is formed as a two-stage stepped groove consisting of a shallow groove portion and a deep groove portion, but the spiral groove may also be formed as a stepped groove with three or more stages in the extension direction of the groove. [Example]

[0074] Next, a mechanical seal according to a sixth embodiment will be described with reference to Fig. 9. Note that a description of the same configuration as in the first embodiment will be omitted.

[0075] 9, a plurality of spiral grooves 613 are provided on a sliding surface 611 of a stationary seal ring 610 in the mechanical seal of this embodiment 6. The spiral grooves 613 extend linearly while inclining with a counterclockwise component from the inner diameter side to the outer diameter side.

[0076] The spiral groove 613 is formed as a stepped groove whose depth decreases from the inner diameter side to the outer diameter side. Specifically, the spiral groove 613 is composed of a substantially rectangular first groove portion 613a, a substantially L-shaped second groove portion 613b that is wider than the first groove portion 613a, and a substantially L-shaped third groove portion 613c that is wider than the second groove portion 613b. In the spiral groove 613, the first groove portion 613a formed on the inner diameter side is deepest, and the second groove portion 613b and the third groove portion 613c are shallower in this order. That is, the spiral groove 613 is formed as a three-stepped groove consisting of the first groove portion 613a, the second groove portion 613b, and the third groove portion 613c. The first groove portion 613a, the second groove portion 613b, and the third groove portion 613c are each formed to a depth sufficient to generate dynamic pressure.

[0077] In addition, in the first groove portion 613a, the second groove portion 613b, and the third groove portion 613c, a first inclined bottom surface 606a, a second inclined bottom surface 606b, and a third inclined bottom surface 606c extending toward the inner diameter side are continuously provided at the inner diameter side edge of each bottom surface. More specifically, the first inclined bottom surface 606a, the second inclined bottom surface 606b, and the third inclined bottom surface 606c are the bottom surfaces of the inclined groove 661. The first inclined bottom surface 606a, the second inclined bottom surface 606b, and the third inclined bottom surface 606c are each parallel to the expansion surface 17a. That is, the inclined groove 661 is formed as a stepped groove whose depth becomes shallower in the relative rotation direction.

[0078] This makes it possible to change the groove portion in the spiral groove 613 that mainly generates positive pressure depending on the relative rotational speed between the stationary seal ring 610 and the rotary seal ring 20. Even in this case, the flow of the atmosphere A introduced into the spiral groove 613 toward the outer diameter side end is promoted, moving in this order through the first groove portion 613a, the second groove portion 613b, and the third groove portion 613c.

[0079] In Example 6, the spiral groove 613 includes the first groove portion 613a, the second groove portion 613b, and the third groove portion 613c. The spiral groove 613 includes the first inclined bottom surface 606a, the second inclined bottom surface 606b, and the third inclined bottom surface 606c, which are respectively continuous with the inner diameter edge of the bottom surface of the inclined groove 661. However, the spiral groove may include, for example, the first groove portion, the second groove portion, and the third groove portion, which are substantially rectangular and have the same width, arranged in succession from the inner diameter side of the spiral groove, and the inner diameter edge of the bottom surface of the first groove portion on the inner diameter side of the spiral groove may be continuous with the inclined bottom surface of the inclined groove. Even in this case, the flow of air A introduced into the spiral groove toward the outer diameter end is promoted through the first groove portion, the second groove portion, and the third groove portion in this order.

[0080] Furthermore, in this Example 6, an example was given of a configuration in which the spiral groove is formed as a three-stage stepped groove consisting of a first groove portion, a second groove portion, and a third groove portion, but the spiral groove may also be formed as a two-stage or four or more-stage stepped groove in the width direction of the groove. [Example]

[0081] Next, a mechanical seal according to a seventh embodiment will be described with reference to Fig. 10. Note that a description of the same configuration as in the first embodiment will be omitted.

[0082] 10 , in the mechanical seal of the seventh embodiment, a sliding surface 711 of a stationary seal ring 710 is provided with a plurality of spiral grooves 13, 715 of different lengths and discharge grooves 716. More specifically, on the inner diameter side of the sliding surface 711, the same spiral grooves 13 as in the first embodiment and spiral grooves 715 longer in the extension direction than the spiral grooves 13 are regularly arranged in the circumferential direction. In addition, on the outer diameter side of the sliding surface 711, discharge grooves 716 (six in the seventh embodiment) are evenly arranged in the circumferential direction.

[0083] The discharge groove 716 is a spiral groove formed on an extension of the spiral groove 13 in the extending direction, and is in communication with the outer space S2 but not with the inner space S1.

[0084] With this, even if contaminants are mixed in when the atmosphere A in the spiral groove 13 flows into between the sliding surfaces 11, 21 due to the relative rotation between the stationary seal ring 710 and the rotary seal ring 20, the contaminants can be collected from between the sliding surfaces 11, 21 into the discharge groove 716 together with the sealed fluid F and the atmosphere A and discharged to the external space S2. Therefore, wear of the sliding surfaces 11, 21 due to the entrapment of contaminants can be suppressed.

[0085] In this Example 7, the shape of the discharge groove 716 is exemplified as a spiral groove formed on an extension of the extension direction of the spiral groove 13, but the shape of the discharge groove may be freely changed as long as it is connected to the outer space S2 and not to the inner space S1. [Example]

[0086] Next, a mechanical seal according to an eighth embodiment will be described with reference to Fig. 11. Note that a description of the same configuration as in the first embodiment will be omitted.

[0087] 11, in the mechanical seal of this embodiment 8, a plurality of dynamic pressure generating mechanisms 813 are provided on the sliding surface 811 of the stationary seal ring 810. The dynamic pressure generating mechanisms 813 are evenly arranged in the circumferential direction on the inner diameter side of the sliding surface 811 (eight in this embodiment 8).

[0088] The dynamic pressure generating mechanism 813 is composed of three spiral grooves 813a, 813b, and 813c. The spiral grooves 813a, 813b, and 813c extend in an arc shape, tilting with a counterclockwise component from the inner diameter side to the outer diameter side. The spiral grooves 813a, 813b, and 813c have different radial and circumferential components in the groove extension direction, with the spiral groove 813a being the shortest, followed by the spiral groove 813b and the spiral groove 813c in order. The outer diameter end face 813d of the spiral groove 813a, the outer diameter end face 813e of the spiral groove 813b, and the outer diameter corner 813f of the spiral groove 813c are aligned in the same circumferential position, i.e., aligned linearly in the radial direction.

[0089] As a result, the spiral grooves 813a, 813b, and 813c that constitute the multiple dynamic pressure generating mechanisms 813, which are evenly arranged circumferentially on the inner diameter side of the sliding surface 811, allow positive pressure to be distributed uniformly in the radial direction of the sliding surface 811. [Example]

[0090] Next, a mechanical seal according to a ninth embodiment will be described with reference to Fig. 12. Note that a description of the same configuration as in the first embodiment will be omitted.

[0091] 12, in the mechanical seal of this ninth embodiment, a plurality of spiral grooves 913 are provided on the sliding surface 911 of the stationary seal ring 910. The spiral grooves 913 are evenly arranged in the circumferential direction on the inner diameter side of the sliding surface 911 (12 grooves in this ninth embodiment).

[0092] The spiral groove 913 extends linearly from the inner diameter side toward the outer diameter side while inclining with a counterclockwise component. Specifically, one side surface 913c of the spiral groove 913 extends in a tangential direction to the inner circumferential surface 910g of the stationary seal ring 910. The other side surface 913b of the spiral groove 913 extends parallel to the one side surface 913c. An outer diameter side end surface 913d of the spiral groove 913 is connected to the outer diameter ends of the side surfaces 913b and 913c perpendicularly, so that the outer diameter side end of the spiral groove 913 forms a rectangular shape. [Example]

[0093] Next, a mechanical seal according to a tenth embodiment will be described with reference to Fig. 13. Note that a description of the same configuration as in the first embodiment will be omitted.

[0094] The mechanical seal of this embodiment 10 differs from the mechanical seal of embodiment 1 in that the spiral grooves are arranged on the outer diameter side of the sliding surface. Also, as shown in Fig. 13, the sealed fluid F exists in the inner space S1 of the mechanical seal, and the atmosphere A exists in the outer space S2, and the inner diameter side of the sliding ring constituting the mechanical seal is the sealed fluid side (high pressure side), and the outer diameter side is the leakage side (low pressure side). Also, the mechanical seal of this embodiment 10 differs from the mechanical seal of embodiment 1 in that the rotary seal ring 20 slides relative to the stationary seal ring 10 in a clockwise direction as shown by the solid arrow.

[0095] 13, a plurality of spiral grooves 1013 are provided on the sliding surface 1011 of the stationary seal ring 1010 in the mechanical seal of this embodiment 10. The spiral grooves 1013 (24 in this embodiment) are evenly arranged in the circumferential direction on the outer diameter side of the sliding surface 1011.

[0096] The edge of the stationary seal ring 1010 on the outer space S2 side is an expansion portion 107, and is provided with a plurality of inclined grooves 1061 and an expansion surface 1017a. In other words, the edge of the stationary seal ring 1010 on the outer diameter side of the sliding surface 1011 is provided with a plurality of inclined grooves 1061 and an expansion surface 1017a.

[0097] Even in this case, the air A is smoothly supplied into the spiral groove 1013 along the inclined bottom surface 1006 that constitutes the inclined groove 1061 . [Example]

[0098] Next, a mechanical seal according to an eleventh embodiment will be described with reference to Fig. 14. Note that a description of the same configuration as in the first embodiment will be omitted.

[0099] 14, in the mechanical seal of this embodiment 11, a plurality of dynamic pressure generating grooves 1116 are provided on the sliding surface 1111 of the stationary seal ring 1110. The dynamic pressure generating grooves 1116 are evenly arranged in the circumferential direction on the inner diameter side of the sliding surface 1111 (24 grooves in this embodiment).

[0100] The dynamic pressure generating grooves 1116 are comprised of spiral grooves 1113 and reverse spiral grooves 1115 that are formed continuously with the spiral grooves 1113 on the outer diameter side thereof, extend in the opposite direction to the spiral grooves 1113, and generate dynamic pressure, forming an L shape. Note that extending in the opposite direction to the spiral grooves means that, while the spiral grooves 1113 extend from the inner diameter side to the outer diameter side while inclining with a component in the forward rotation direction, the reverse spiral grooves 1115 extend from the inner diameter side to the outer diameter side while inclining with a component in the reverse rotation direction.

[0101] The reverse spiral groove 1115 extends linearly from the inner diameter side end toward the outer diameter side while being inclined in the reverse rotation direction of the rotary seal ring 20, and the outer diameter side end, i.e., the outer diameter end of the dynamic pressure generating groove 1116, is closed so as not to be in communication with the external space S2. Note that the reverse spiral groove 1115 is not limited to extending linearly while being inclined, but may extend in an arc shape.

[0102] Furthermore, the extension distance of the reverse spiral groove 1115 is shorter than the extension distance of the spiral groove 1113 .

[0103] The depth of the reverse spiral groove 1115 is the same as the depth of the spiral groove 1113. That is, the bottom surface of the reverse spiral groove 1115 is disposed in the same plane as the bottom surface of the continuous spiral groove 1113, forming a flat surface. Note that the bottom surfaces of the spiral groove 1113 and the reverse spiral groove 1115 are not limited to being flat surfaces, and may have slopes or irregularities.

[0104] According to this, during forward rotation of the rotary seal ring 20, the positive pressure generated in the dynamic pressure generating groove 1116, mainly in the spiral groove 1113, sucks in the atmosphere A that has flowed from the inner space S1 between the sliding surfaces 1111, 21, and pushes the sealed fluid F back toward the outer space S2, thereby suppressing leakage of the sealed fluid F from between the sliding surfaces 1111, 21 into the inner space S1. On the other hand, during reverse rotation of the rotary seal ring 20, the sealed fluid F that has entered the reverse spiral groove 1115 on the outer diameter side of the spiral groove 1113 follows due to shear with the sliding surface 21 of the rotary seal ring 20 and is returned from the outer diameter side end of the reverse spiral groove 1115 toward the outer space S2 to between the sliding surfaces 1111, 21, thereby reducing leakage of the sealed fluid F into the inner space S1. In this way, the dynamic pressure generating groove 1116 has the spiral groove 1113 and the reverse spiral groove 1115 which have different rotation directions for generating the main dynamic pressure, so that the sliding surfaces 1111, 21 can be separated from each other during both rotations, thereby suppressing wear and also suppressing leakage of the sealed fluid F from between the sliding surfaces 1111, 21 into the internal space S1.

[0105] Furthermore, since the dynamic pressure generating groove 1116 is formed in an L-shape by the spiral groove 1113 and the reverse spiral groove 1115, during forward rotation, the air A drawn from the inner space S1 into the spiral groove 1113 and the sealed fluid F drawn from the outer diameter end into the reverse spiral groove 1115 are collected at the acute angle portion 1116C, generating positive pressure. During reverse rotation, the sealed fluid F is pushed back toward the outer space S2 by the dynamic pressure generated in the reverse spiral groove 1115, so that the intrusion of the sealed fluid F into the spiral groove 1113 can be suppressed, and leakage of the sealed fluid F through the spiral groove 1113 into the inner space S1 can be suppressed. [Example]

[0106] Next, a mechanical seal according to a twelfth embodiment will be described with reference to Fig. 15. Note that the description of the same configuration as that of the eleventh embodiment will be omitted.

[0107] 15, in the mechanical seal of this embodiment 12, the dynamic pressure generating groove 1216 on the sliding surface 1211 of the stationary seal ring 1210 is composed of a spiral groove 1213 that extends from the inner diameter side toward the outer diameter side and generates dynamic pressure, and a reverse spiral groove 1215 that is spaced apart radially on the outer diameter side of the spiral groove 1213, extends in the opposite direction to the spiral groove 1213, and generates dynamic pressure. In other words, the dynamic pressure generating groove 1216 is configured such that the spiral groove 1213 and the reverse spiral groove 1215 are separated radially by the annular land portion 1212d.

[0108] More specifically, the spiral groove 1213 has an inner diameter end that communicates with the inner space S1, and extends in an arc shape from the inner diameter end toward the outer diameter side while inclining in the forward rotation direction of the rotating seal ring 20, and the linear outer diameter end of the spiral groove 1213 is closed so as not to communicate with the reverse spiral groove 1215.

[0109] The reverse spiral groove 1215 is approximately parallelogram-shaped and extends linearly from the inner diameter end toward the outer diameter side while inclining in the reverse rotation direction of the rotating seal ring 20, and the outer diameter end is closed so as not to be in communication with the outer space S2.

[0110] According to this, during forward rotation of the rotary seal ring 20, the sealed fluid F that has flowed from the outer space S2 between the sliding surfaces 1211, 21 is sucked in by the positive pressures generated in the spiral groove 1213 and the reverse spiral groove 1215 of the dynamic pressure generating groove 1216 and pushed back toward the outer space S2, thereby suppressing leakage of the sealed fluid F from between the sliding surfaces 1211, 21 into the inner space S1. On the other hand, during reverse rotation of the rotary seal ring 20, the sealed fluid F that has entered the reverse spiral groove 1215 on the outer diameter side of the spiral groove 1213 follows due to shear with the sliding surface 21 of the rotary seal ring 20 and is returned from the end of the reverse spiral groove 1215 on the sealed fluid F side toward the outer diameter side to between the sliding surfaces 1211, 21, thereby reducing leakage of the sealed fluid F into the inner space S1. In this way, the dynamic pressure generating groove 1216 has the spiral groove 1213 and the reverse spiral groove 1215 which have different rotation directions for generating the main dynamic pressure, so that the sliding surfaces 1211, 21 can be separated from each other during both rotations, thereby suppressing wear and also suppressing leakage of the sealed fluid F from between the sliding surfaces 1211, 21 into the internal space S1.

[0111] Furthermore, an annular land portion 1212d that is continuous in the circumferential direction and has a radial width of at least a predetermined value is formed between the spiral groove 1213 and the reverse spiral groove 1215. The spiral groove 1213 and the reverse spiral groove 1215 are separated by this annular land portion 1212d. As a result, during reverse rotation of the rotary seal ring 20, the sealed fluid F is sucked into the reverse spiral groove 1215 from the acute angle portion 1215C on the outer diameter side of the annular land portion 1212d and captured therein. This prevents the sealed fluid F from crossing the annular land portion 1212d and entering the spiral groove 1213, thereby further reducing the amount of sealed fluid F that leaks into the internal space S1 through the spiral groove 1213.

[0112] Furthermore, since the spiral groove 1213 and the reverse spiral groove 1215 are separated by the annular land portion 1212d, the spiral groove 1213 and the reverse spiral groove 1215 do not interfere with each other's dynamic pressure generation during both rotations, making it easier to exert the dynamic pressure effect.

[0113] 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.

[0114] For example, in the above embodiment, a mechanical seal is used as an example of the sliding component, but the sliding component may be a shaft seal component other than a mechanical seal.Furthermore, the sliding component may be a component other than a shaft seal component, such as a bearing component.

[0115] In addition, in the above-described Examples 1 to 12, examples were described in which spiral grooves or reverse spiral grooves were provided on the stationary seal ring, but spiral grooves or reverse spiral grooves 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 stationary seal ring or a rotary seal ring.

[0116] In addition, in the above-described embodiments 1 to 12, the sealed fluid side has been described as the high pressure side and the leakage side as the low pressure side, but the sealed fluid side and the leakage side may be at approximately the same pressure.

[0117] In addition, in the above-described embodiments 1 to 12, the sealed fluid F is described as a high-pressure liquid, but it is not limited to this and may be a gas or a low-pressure liquid, or may be a mist in which a liquid and a gas are mixed.

[0118] Furthermore, in the above-described Examples 1 to 12, the fluid on the leakage side was described as being the atmosphere A, which is a low-pressure gas, but it is not limited to this and may be a liquid or a high-pressure gas, or may be a mist-like mixture of liquid and gas. [Explanation of symbols]

[0119] 1 Rotation axis 2 sleeves 4. Housing 6 Slanted bottom 10 Stationary seal ring (one of the sliding rings) 10g Inner surface (surface on one space side) 11 Sliding surface 12 rand 13 Spiral groove 13A aperture 13B Corner 13a Bottom 13b,13c side 13d end face 13g edge 17 Expansion section 20 Rotating seal ring (other sliding ring) 21 Sliding surface 61 Slant groove A. Atmosphere F Sealed fluid S1 Internal space (leak side space) S2 Outer space (space on the sealed fluid side) S11 Communication space

Claims

1. A pair of sliding rings that slide relative to each other are provided, one of the spaces on the outer diameter side and the inner diameter side of the pair of sliding rings is a space on the sealed fluid side, and the other space is a space on the leakage side, a sliding component in which a dynamic pressure generating groove communicating with the leakage side space is provided on the sliding surface of the one sliding ring, an expanded portion is formed on the edge portion of the one sliding ring on the leakage side, the expanded portion continuing from the sliding surface of the one sliding ring and expanding toward the space on the leakage side, The expanding portion is provided with an inclined groove that is continuous with the dynamic pressure generating groove and extends toward the leakage side space.

2. The sliding element according to claim 1 , wherein the inclined groove extends to the peripheral surface of the one sliding ring on the leakage side.

3. 2. The sliding component according to claim 1, wherein a bottom surface of the hydrodynamic groove and a bottom surface of the inclined groove form an obtuse angle.

4. 4. The sliding element according to claim 1, wherein the inclined groove is formed by an inclined bottom surface that is continuous with the bottom surface of the dynamic pressure generating groove, and side surfaces that rise from both circumferential end edges of the inclined bottom surface.

5. 2. The sliding element according to claim 1, wherein the inclined groove is formed to a constant depth.

6. 6. The sliding element according to claim 5, wherein the inclined grooves are formed to the same depth as the dynamic pressure generating grooves.

7. 2. The sliding component according to claim 1, wherein the sliding surface of one of the sliding rings is provided with a reverse dynamic pressure generating groove that is provided on the sealed fluid side of the dynamic pressure generating groove and extends in a direction opposite to the dynamic pressure generating groove to generate dynamic pressure.

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