Sliding component

Abstract

Provided is a sliding component such that it is possible to disperse the locations where dynamic pressure is generated.　A sliding component in which a pair of sliding surfaces 11, 21 are positioned at locations that rotate relative to each other and a dynamic pressure generation mechanism 12 is provided on one of the sliding surfaces 11, wherein the dynamic pressure generation mechanism 12 includes a shallow groove 14 that extends to the relative-rotation downstream side and has a closed end 14a that is closed, and at least one deep groove 16 intersecting the extension direction of the shallow groove 14, and the shallow groove 14 has an upstream region 17 on the relative-rotation upstream side of the deep groove 16, and a downstream region 18 on the relative-rotation downstream side of the deep groove 16.

Description

Sliding component

[0001] The present invention relates to sliding components that rotate relative to each other, and is used, for example, for sliding components used in shaft sealing devices that seal the rotating shafts of rotating machines in the automotive, general industrial machinery, or other sealing fields, or for sliding components used in bearings of machines in the automotive, general industrial machinery, or other bearing fields.

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

[0003] For example, on the sliding surface of one of the sliding rings of the mechanical seal shown in Patent Document 1, a plurality of spiral grooves are formed that communicate with the inner diameter side space, which is the low-pressure side, and extend toward the outer diameter side space, which is the high-pressure side, and the relative rotation downstream side. When the pair of sliding rings rotate relative to each other, the atmosphere in the inner diameter side space is introduced to the closed end located on the outer diameter side in the spiral groove, and hydrodynamic pressure can be generated at the closed end and its vicinity. As a result, the sliding surfaces are slightly separated from each other, so that the frictional force generated when the sliding surfaces rotate relative to each other can be reduced.

[0004] On the sliding surface of one of the sliding rings of such a mechanical seal, there are also some in which a plurality of spiral grooves are formed that communicate with the space into which the fluid to be sealed flows and extend toward the leakage side space and the relative rotation downstream side. Even with such a configuration, when the pair of sliding rings rotate relative to each other, the hydrodynamic pressure generated at the closed end and its vicinity using the fluid to be sealed causes the sliding surfaces to be slightly separated from each other, and the frictional force generated when the sliding surfaces rotate relative to each other can be reduced.

[0005] Microfilm of Japanese Utility Model Application No. 59-13126 (Japanese Utility Model Publication No. 60-126762) (page 3, figure 2)

[0006] However, in the mechanical seal described in Patent Document 1, dynamic pressure is generated only at the closed end of each spiral groove and in its vicinity. As a result, the points where dynamic pressure is generated are far apart, and there is a risk that the sliding surfaces may tilt relative to each other.

[0007] This invention was made in view of these problems, and aims to provide a sliding component that can distribute the points where dynamic pressure is generated.

[0008] To solve the aforementioned problems, the present invention provides a sliding component in which a pair of sliding surfaces are arranged at a location where they rotate relative to each other, and at least one of the sliding surfaces is equipped with a dynamic pressure generating mechanism, wherein the dynamic pressure generating mechanism comprises a shallow groove having a closed end that extends downstream of the relative rotation and is closed, and at least one deep groove intersecting the extension direction of the shallow groove, wherein the shallow groove has an upstream region upstream of the relative rotation of the deep groove and a downstream region downstream of the relative rotation of the deep groove. With this, the fluid flowing along the shallow groove generates dynamic pressure not only at the closed end but also near the deep groove, thus dispersing the locations where dynamic pressure is generated.

[0009] The dynamic pressure generating mechanism may communicate with one of the spaces and have a communication portion that is deeper than the shallow groove. This makes it possible to increase the efficiency of introducing fluid from one of the spaces.

[0010] The deep groove may extend across both sides of the shallow groove. This makes it easier to guide the fluid flowing along the shallow groove into the deep groove, thereby increasing the efficiency of dynamic pressure generation.

[0011] The shallow groove may have a tapered shape that narrows towards the closed end. This can improve the efficiency of dynamic pressure generation at and near the closed end.

[0012] The deep groove may have at least two connecting sections, one on the upstream side of relative rotation which communicates with the upstream region and the other on the downstream side of relative rotation which communicates with the downstream region, and a downstream connecting section, one on the upstream side of relative rotation which faces a land and the other on the downstream side of relative rotation which communicates with the downstream region. This makes it possible to increase the efficiency of fluid recovery into the deep groove.

[0013] The deep groove may have at least two communicating sections, one on the upstream side of relative rotation which communicates with the upstream region and the other on the downstream side of relative rotation which communicates with the downstream region, and an upstream communicating section, one on the upstream side of relative rotation which communicates with the upstream region and the other on the downstream side of relative rotation which faces the land. This makes it easier to supply fluid from the upstream region to the land.

[0014] The extension direction may differ between the downstream side of the relative rotation in the upstream region and the downstream side of the relative rotation in the downstream region. This allows the direction in which the fluid is guided to differ between the upstream and downstream regions, thereby enabling the fluid to be supplied from the shallow groove to a wide area of ​​the land.

[0015] The shallow groove may extend inclined from one space to the other. This allows dynamic pressure to be generated at different radial positions.

[0016] Multiple dynamic pressure generating mechanisms may be provided in the circumferential direction. This allows for the generation of dynamic pressure in a balanced manner in the circumferential direction.

[0017] To solve the aforementioned problems, the sliding component of the present invention is a sliding component in which a pair of sliding surfaces are arranged at a location where they rotate relative to each other, and at least one of the sliding surfaces is equipped with a dynamic pressure generating mechanism, wherein the dynamic pressure generating mechanism has a plurality of grooves that become shallower toward the downstream side of the relative rotation, and the groove located furthest downstream has a closed end that is closed toward the downstream side of the relative rotation. With this, the fluid flowing along the plurality of grooves generates dynamic pressure not only at the closed end but also near the connection portion between adjacent grooves, so that the locations where dynamic pressure is generated can be dispersed.

[0018] This is a longitudinal cross-sectional view showing an example of a mechanical seal in Embodiment 1 of the present invention. This is a view of the sliding surface of the stationary sealing ring in Embodiment 1 from the axial direction. This is an enlarged view of the main part of Figure 2. This is a cross-sectional view taken along line A-A in Figure 3. This is an enlarged view of the main part of the sliding surface of the stationary sealing ring as Modification 1-1. This is a diagram showing an example of a thrust bearing and a radial bearing as Modification 1-2. This is a diagram showing the sliding surface of a radial bearing. This is a view of the sliding surface of the stationary sealing ring in Embodiment 2 of the present invention from the axial direction. This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in Embodiment 2. This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in Embodiment 3 of the present invention. This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in Embodiment 4 of the present invention. This is a diagram of a dynamic pressure generation mechanism as Modification 4-1. This is a view of the sliding surface of the stationary sealing ring in Embodiment 5 of the present invention from the axial direction. This is an enlarged view of the main part of the sliding surface of the stationary sealing ring in Embodiment 5. This is a cross-sectional view of the stationary sealing ring in Embodiment 6 of the present invention. This is a diagram of a dynamic pressure generation mechanism as Modification 7-1. This is a cross-sectional view of the stationary sealing ring as Modification 7-2.

[0019] Embodiments for implementing the sliding component according to the present invention will be described below based on examples.

[0020] The sliding component according to Example 1 will be described with reference to Figures 1 to 7. In this example, a mechanical seal will be used as an example of a sliding component. Also, for the sake of explanation, dots may be added to grooves and the like formed on the sliding surface in the drawings.

[0021] The mechanical seal shown in Figure 1 separates the outer space S1, where the sealed fluid F such as oil is present, from the inner space S2, where the atmosphere A is present. In other words, the mechanical seal is an inside type that seals the sealed fluid F that would otherwise leak from the outer space S1 to the inner space S2.

[0022] In this embodiment, we illustrate a configuration in which the atmosphere A is at a lower pressure than the sealed fluid F. Furthermore, the types of fluids present in the outer space S1 and inner space S2 may be changed as appropriate. Additionally, the fluids present in the outer space S1 and inner space S2 may be the same fluid, and their pressures may be the same.

[0023] The mechanical seal comprises a stationary sealing ring 10 and a rotating sealing ring 20. The stationary sealing ring 10 is fixed to a seal cover 5 which is fixed to the housing 4 of the equipment to be mounted, in a non-rotatable and axially movable state. The rotating sealing ring 20 is attached to a sleeve 2 which is fixed to a rotating shaft 1, and is rotatable together with the rotating shaft 1.

[0024] The stationary sealing ring 10 is biased axially by the elastic member 7. The sliding surface 11 of the stationary sealing ring 10, which serves as one sliding surface, and the sliding surface 21 of the rotating sealing ring 20, which serves as the other sliding surface, are in close contact with each other. The sliding surface 21 of the rotating sealing ring 20 is a flat surface and does not have any grooves or other recesses.

[0025] The stationary sealing ring 10 and the rotating sealing ring 20 are typically formed from two SiC (hard material) components or a combination of SiC (hard material) and carbon (soft material), but are not limited to these; any sliding material used for mechanical seals is applicable. SiC can be sintered using boron, aluminum, carbon, etc., as sintering aids, or from materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, SiC-TiN, etc. Carbon can be a mixture of carbonaceous and graphite, as well as resin-molded carbon and sintered carbon. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), and composite materials are also applicable.

[0026] As shown in Figure 2, the rotating sealing ring 20 slides relative to the stationary sealing ring 10 in a counterclockwise direction as indicated by the solid arrow. In this embodiment, with this relative rotation direction as the reference, the clockwise side from the target position is described as the upstream side in the relative rotation direction, and the counterclockwise side from the target position is described as the downstream side in the relative rotation direction.

[0027] Multiple dynamic pressure generating mechanisms 12 are evenly arranged in the circumferential direction on the sliding surface 11 of the stationary sealing ring 10 (24 in this embodiment). The parts of the sliding surface 11 other than the dynamic pressure generating mechanisms 12 form flat lands 13. The number and arrangement of the dynamic pressure generating mechanisms 12 may be changed as appropriate.

[0028] The dynamic pressure generating mechanism 12 has a first deep groove 15 that communicates with the outer space S1, and within that, a second deep groove 16 is provided that intersects the direction of extension of the shallow groove 14. This second deep groove 16 divides the shallow groove 14 into a first shallow groove 17 and a second shallow groove 18. In other words, the dynamic pressure generating mechanism 12 has, in order from the upstream side in the direction of rotation, a first deep groove 15, a first shallow groove 17, a second deep groove 16, and a second shallow groove 18. The first shallow groove 17 is also called the upstream region, and the second shallow groove 18 is also called the downstream region.

[0029] The extension direction of the shallow groove 14 is the direction in which the shallow groove 14 extends from the first deep groove 15 toward the closed end 14a, which will be described later, toward the downstream side in the rotational direction in the circumferential direction and toward the inner diameter in the radial direction, as indicated by the dashed arrow E1 in Figure 3. Furthermore, "intersecting with the extension direction" does not mean being perpendicular to the extension direction, and the angle with respect to the extension direction may be changed as appropriate. In particular, the angle with respect to the extension direction is preferably 45 degrees or more, and more preferably 60 degrees or more, as it makes it easier to generate positive pressure at a more distant position, which will be described in more detail later.

[0030] As shown in Figure 3, the first deep groove 15 is a triangular groove when viewed from the axial direction, and its width narrows from the outer diameter end communicating with the outer space S1 toward the inner diameter and toward the downstream side in the relative rotation direction.

[0031] In the following explanation, the upstream side in the relative rotation direction may simply be referred to as the "upstream side," and the downstream side in the relative rotation direction may simply be referred to as the "downstream side."

[0032] As shown in Figure 4, the first deep groove 15 is a groove with a depth D1, i.e., an axial length that is approximately constant. Furthermore, the first deep groove 15 is formed with a depth D1 that is deeper than the depth D2 of the shallow groove 14 (D1 > D2). More specifically, the depth D1 is approximately 5 to 50 times the depth D2 (D1 ≈ D2 × 5 to 50). Note that in Figure 4, the depths D1 and D2 have been exaggerated in the illustration to make them clearer.

[0033] Furthermore, the depth of the first deep groove 15 may change, for example, becoming shallower from the outer diameter side towards the inner diameter side and downstream in the relative rotation direction. Also, although the cross-sectional shape of the first deep groove 15 is rectangular, it may be U-shaped, semicircular, or triangular, and may be changed as appropriate. The same applies to the other grooves 14 and 16 in terms of depth and cross-sectional shape.

[0034] As shown in Figure 3, the shallow groove 14 has a so-called spiral groove shape, extending in an arc shape from the first deep groove 15, which serves as a communication section at the outer diameter end, towards the inner diameter and downstream in the relative rotation direction. The shallow groove 14 has an arc shape that protrudes toward the outer diameter and downstream. The sealed fluid F present in the outer space S1 can flow into the shallow groove 14 through the first deep groove 15.

[0035] The inner diameter end of the shallow groove 14 is a closed end 14a that is closed off so as not to communicate with the inner space S2.

[0036] As shown in Figure 4, the shallow groove 14 is a groove with a depth D2 that is approximately constant. In other words, the first shallow groove 17 and the second shallow groove 18 each have a depth D2 that is approximately constant. However, the depths of the first shallow groove 17 and the second shallow groove 18 may be different.

[0037] As shown in Figure 3, the first shallow groove 17 is located upstream of the second deep groove 16 and communicates with both the first deep groove 15 and the second deep groove 16. The first shallow groove 17 widens from the first deep groove 15 located upstream to the second deep groove 16 located downstream. In other words, the first shallow groove 17 is widest at its downstream end 17a, and this end 17a communicates with the second deep groove 16.

[0038] The first shallow groove 17 is defined by a flat bottom surface, a first outer diameter side surface 12a that extends axially toward the front side of the paper in Figure 3, i.e., toward the rotating sealing ring 20, substantially perpendicular to the outer diameter edge of the bottom surface, and a first inner diameter side surface 12b that extends axially toward the front side of the paper in Figure 3, substantially perpendicular to the inner diameter edge of the bottom surface.

[0039] The first outer diameter side surface 12a extends in a curved manner, inclined toward the inner diameter and downstream side from the outer diameter edge of the sliding surface 11, projecting toward the outer space S1. The downstream end of the first outer diameter side surface 12a faces the second deep groove 16. The first side surface 12a may be curved to project toward the inner space S2, or it may extend in a straight line. The same applies to the second outer diameter side surface 12c, which will be described later.

[0040] The first inner diameter side surface 12b curves outward from the outer diameter edge of the sliding surface 11 upstream of the first outer diameter side surface 12a, inclined inward and downstream, and protruding toward the outer space S1. The upstream end of the first inner diameter side surface 12b faces the first deep groove 15. The first side surface 12b may be curved to protrude toward the inner space S2, or it may extend in a straight line. The same applies to the second inner diameter side surface 12d, which will be described later.

[0041] Furthermore, the direction of protrusion in the curved shape of the first side surface 12a on the outer diameter side and the direction of protrusion in the curved shape of the first side surface 12b on the inner diameter side may be different. The same applies to the second side surface 12c on the outer diameter side and the second side surface 12d on the inner diameter side, which will be described later.

[0042] As shown in Figure 4, the second deep groove 16 is a groove with a substantially constant depth D1. In other words, the depth D1 of the second deep groove 16 is substantially the same as the depth D1 of the first deep groove 15. Note that the depths of the first deep groove 15 and the second deep groove 16 may be different. Furthermore, the depths of the double-sided connecting section 16a and the downstream connecting section 16b, the depths of the double-sided connecting section 16a and the upstream connecting section 16c, and the depths of the downstream connecting section 16b and the upstream connecting section 16c may be different.

[0043] Returning to FIG. 3, the second deep groove 16 is formed in a V shape that opens to the downstream side when viewed from the axial direction. The second deep groove 16 includes both-side communication portions 16a and an upstream-side communication portion 16c that are inclined from the outer diameter side toward the inner diameter side and the upstream side and extend linearly, and a downstream-side communication portion 16b that extends linearly substantially along the radial direction of the sliding surface 11 from the inner diameter side end in the both-side communication portion 16a. Note that the second deep groove 16 is not limited to a V shape that opens to the downstream side, and may be a V shape that opens to the upstream side, a curved shape, or a linear shape, and its shape may be changed as appropriate.

[0044] The both-side communication portions 16a and the upstream-side communication portion 16c extend across the downstream end 17a in the first shallow groove 17. That is, the both-side communication portions 16a and the upstream-side communication portion 16c communicate across the width of the downstream end 17a.

[0045] Further, the upstream side of the both-side communication portion 16a communicates with the first shallow groove 17, and the downstream side thereof communicates with the second shallow groove 18.

[0046] The upstream-side communication portion 16c is a portion that extends from the outer diameter side end of the both-side communication portion 16a toward the outer diameter side and the downstream side. The upstream side of the upstream-side communication portion 16c communicates with the first shallow groove 17, and the downstream side thereof faces the land 13. That is, the upstream-side communication portion 16c is a portion that does not communicate with the second shallow groove 18 and communicates only with the first shallow groove 17.

[0047] In other words, the upstream-side communication portion 16c and the corner 17b that communicates with the upstream-side communication portion 16c at the downstream end 17a are formed on the outer diameter side of the second shallow groove 18. More specifically, the corner 17b corresponds to a portion of the corner of the bottom surface where the first side surface 12a on the outer diameter side intersects the boundary between the first shallow groove 17 and the second deep groove 16.

[0048] The upstream-side communication portion 16c and the corner 17b are formed at substantially the same position as the first deep groove 15 in the radial center. Further, the upstream-side communication portion 16c and the corner 17b are formed at substantially the same position as the first deep groove 15 in the radial center in the adjacent downstream dynamic pressure generation mechanism 12.

[0049] The two side connecting sections 16a and the downstream side connecting section 16b extend across the upstream end 18a of the second shallow groove 18. In other words, the two side connecting sections 16a and the downstream side connecting section 16b communicate across the width of the upstream end 18a of the second shallow groove 18.

[0050] The downstream connecting section 16b has its upstream side facing the land 13 and its downstream side communicating with the second shallow groove 18. In other words, the downstream connecting section 16b is not communicating with the first shallow groove 17 and is communicating only with the second shallow groove 18.

[0051] As described above, the two side connecting sections 16a and the upstream side connecting section 16c in the second deep groove 16 extend to the downstream end 17a of the first shallow groove 17. The two side connecting sections 16a and the downstream side connecting section 16b extend to the upstream end 18a of the second shallow groove 18.

[0052] In other words, the second deep groove 16 crosses the direction of extension of the shallow groove 14 and extends across the direction that intersects the shallow groove 14, or in other words, across the first outer diameter side surface 12a and the second inner diameter side surface 12d, which will be described later. Furthermore, there are no regions that are not in communication with the second deep groove 16 at the downstream end 17a of the first shallow groove 17 and the upstream end 18a of the second shallow groove 18.

[0053] Here, in the connecting sections 16a on both sides, the shortest length from the first shallow groove 17 to the second shallow groove 18 is defined as dimension L1. Also, in the connecting section 16b on the downstream side, the shortest length from the land 13 on the inner diameter side of the first shallow groove 17 to the second shallow groove 18 is defined as dimension L2. Also, in the connecting section 16c on the upstream side, the shortest length from the first shallow groove 17 to the land 13 on the outer diameter side of the second shallow groove 18 is dimension L1. Dimensions L1 and L2 are approximately the same and shorter than the depth D1 (L1 = L2 < D1).

[0054] For more details, please refer to Figure 4. The first shallow groove 17 is formed such that its maximum flow channel cross-sectional area s1 is narrower than the minimum flow channel cross-sectional area s2 of the second deep groove 16 (s1 < s2). Note that the flow channel cross-sectional areas s1 and s2 shown in Figure 4 are schematic representations.

[0055] Returning to Figure 3, the second shallow groove 18 is located downstream of the second deep groove 16, and its upstream end 18a communicates with the second deep groove 16. The second shallow groove 18 has a tapered shape, becoming narrower from the upstream end 18a towards the closed end 14a located downstream.

[0056] The second shallow groove 18 is defined by a flat bottom surface, a second outer diameter side surface 12c that extends axially toward the front side of the paper in Figure 3, i.e., toward the rotating sealing ring 20, substantially perpendicular to the outer diameter edge of the bottom surface, and a second inner diameter side surface 12d that extends axially toward the front side of the paper in Figure 3, substantially perpendicular to the inner diameter edge of the bottom surface.

[0057] The second outer diameter side surface 12c extends in a curved manner, inclined inward and downstream from a position spaced further inward than the downstream end of the first outer diameter side surface 12a, so as to protrude toward the outer space S1. The second inner diameter side surface 12d extends in a curved manner, inclined inward and downstream from the portion facing the downstream communication portion 16b of the second deep groove 16, so as to protrude toward the outer space S1. Furthermore, the downstream ends of the second inner diameter side surface 12d and the second outer diameter side surface 12c intersect to form the closed end 14a of the shallow groove 14.

[0058] The closed end 14a of the shallow groove 14 is formed at approximately the same radial center as the downstream communication portion 16b of the second deep groove 16 in the adjacent downstream dynamic pressure generating mechanism 12.

[0059] Next, the sealing between the outer space S1 and the inner space S2 by the stationary sealing ring 10 and the rotating sealing ring 20 will be explained using Figure 3. Note that the fluid flow in Figure 3 is shown in a schematic manner.

[0060] When the rotating sealing ring 20 is not rotating and the mechanical seal is inactive, the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 are in contact. This prevents the sealed fluid F from leaking into the internal space S2.

[0061] When the rotating sealing ring 20 is rotating relative to the other, as shown by the black arrow in Figure 3, the sealed fluid F inside the dynamic pressure generating mechanism 12 attempts to move in the direction of rotation of the rotating sealing ring 20 due to shear with the sliding surface 21.

[0062] The sealed fluid F in the first deep groove 15 flows downstream along the circumferential direction and flows into the first shallow groove 17.

[0063] The sealed fluid F that flows from the first deep groove 15 into the first shallow groove 17 flows circumferentially towards the downstream end 17a. Furthermore, since the corner 17b is formed at approximately the same position as the first deep groove 15 and the radial center, the sealed fluid F is more likely to flow towards the corner 17b located downstream. In addition, the sealed fluid F that has moved toward the first side surface 12a is guided toward the corner 17b by the first side surface 12a.

[0064] As a result, the flow of the sealed fluid F in the first shallow groove 17 has a larger component directed downstream in the circumferential direction than the component directed inward. Therefore, the sealed fluid F in the first shallow groove 17 tends to flow almost along the circumferential direction, with a slight inclination towards the inward direction from upstream to downstream, as indicated by the black arrows.

[0065] The sealed fluid F that has moved towards corner 17b collides with the sealed fluid F in the upstream communication portion 16c of the second deep groove 16, as will be described in more detail later, and is supplied between the land 13 and the sliding surface 21 from corner 17b and its vicinity. Positive pressure is generated at corner 17b and its vicinity.

[0066] Furthermore, some of the sealed fluid F directly collides with the sealed fluid F within the two-sided connecting section 16a. As a result, positive pressure is generated even in the vicinity of the two-sided connecting section 16a, which is on the inner diameter side of the upstream connecting section 16c.

[0067] Furthermore, a relative negative pressure is generated on the upstream side of the first shallow groove 17, that is, on the side of the first deep groove 15. This negative pressure increases as it approaches the first deep groove 15. In other words, the force drawing in the sealed fluid F becomes stronger. Because this negative pressure makes it easier for the sealed fluid F in the first deep groove 15 to be drawn into the first shallow groove 17, a stable positive pressure can be generated at and near the boundary between the downstream end 17a and the second deep groove 16. Hereafter, the relative negative pressure will be simply referred to as "negative pressure".

[0068] The sealed fluid F supplied between the land 13 and the sliding surface 21 from corner 17b and its vicinity is collected in the first deep groove 15 and the first shallow groove 17 in the adjacent downstream dynamic pressure generating mechanism 12.

[0069] The sealed fluid F in the second deep groove 16 flows downstream along the circumferential direction and flows into the second shallow groove 18.

[0070] The sealed fluid F that flows from the second deep groove 16 into the second shallow groove 18 is easily guided towards the closed end 14a by the second side surface 12c on the outer diameter side and the second side surface 12d on the inner diameter side, because the entire upstream end 18a is in communication with the second deep groove 16. The sealed fluid F guided towards the closed end 14a is supplied between the land 13 and the sliding surface 21 from the closed end 14a and its vicinity. Positive pressure is generated at the closed end 14a and its vicinity.

[0071] The second side surface 12c on the outer diameter side guides the sealed fluid F toward the inner diameter side. The second side surface 12d on the inner diameter side guides the sealed fluid F toward the outer diameter side.

[0072] Furthermore, the inclination of the second side surface 12c on the outer diameter side with respect to the circumferential direction, with respect to its upstream end, is greater than the inclination of the second side surface 12d on the inner diameter side with respect to the circumferential direction, with respect to its upstream end.

[0073] As a result, the component of the sealed fluid F in the second shallow groove 18 that is guided toward the inner diameter side by the second side surface 12c on the outer diameter side is larger than the component that is guided toward the outer diameter side by the second side surface 12d on the inner diameter side. Therefore, the sealed fluid F in the second shallow groove 18 is more likely to flow inclined toward the inner diameter side.

[0074] Furthermore, the sealed fluid F in the second shallow groove 18 is guided by the second side surface 12d on the inner diameter side, and a component directed toward the outer diameter side prevents it from excessively inclining toward the inner diameter side from upstream to downstream and flowing toward the inner space S2.

[0075] Furthermore, the first outer diameter side surface 12a, which serves as the downstream side of relative rotation in the first shallow groove 17, and the second outer diameter side surface 12c, which serves as the downstream side of relative rotation in the second shallow groove 18, have different directions of extension. More specifically, the inclination of the second outer diameter side surface 12c with respect to the circumferential direction, with its upstream end as the reference point, is greater than the inclination of the first outer diameter side surface 12a with respect to the circumferential direction, with respect to its upstream end as the reference point.

[0076] As a result, the flow of the sealed fluid F in the second shallow groove 18 has a larger component directed towards the inner diameter than the flow of the sealed fluid F in the first shallow groove 17. Therefore, as shown by the black arrow, the slope of the flow of the sealed fluid F in the second shallow groove 18 is greater toward the inner diameter than that of the sealed fluid F in the first shallow groove 17.

[0077] Furthermore, at the upstream end 18a of the second shallow groove 18, that is, the side facing the second deep groove 16, a larger negative pressure is generated as one approaches the second deep groove 16. This negative pressure makes it easier for the sealed fluid F in the second deep groove 16 to be drawn into the second shallow groove 18, thereby enabling the stable generation of positive pressure at and near the closed end 14a.

[0078] The sealed fluid F supplied between the land 13 and the sliding surface 21 from the closed end 14a and its vicinity is collected in the downstream communication portion 16b of the second deep groove 16 in the adjacent downstream dynamic pressure generating mechanism 12.

[0079] Furthermore, the main flow direction of the sealed fluid F supplied from the closed end 14a and its vicinity is approximately perpendicular to the radial center of the downstream communication section 16b in the second deep groove 16 of the adjacent downstream dynamic pressure generating mechanism 12, as indicated by the black arrow. As a result, the sealed fluid F is easily recovered in the downstream communication section 16b.

[0080] As described above, the positive pressure generated by the dynamic pressure generating mechanism 12 can slightly separate the sliding surfaces 11 and 21. This allows the sealed fluid F and the atmosphere A to flow into the space between the sliding surfaces 11 and 21. Furthermore, the dynamic pressure generating mechanism 12 is in communication with the outer space S1, making it easier to guide the sealed fluid F towards the closed end 14a. As a result, the sealed fluid F can easily flow into the inner diameter side between the sliding surfaces 11 and 21, so that the sliding surfaces 11 and 21 are primarily lubricated by liquid, and the frictional force due to relative sliding is reduced.

[0081] Furthermore, the sealed fluid F supplied between the land 13 and the sliding surface 21 from the dynamic pressure generating mechanism 12 is recovered by the adjacent dynamic pressure generating mechanism 12 downstream, making it less likely to leak into the internal space S2.

[0082] Next, the positive pressure generated at the boundary between the downstream end 17a and the second deep groove 16 and in its vicinity will be explained with reference to Figure 4. In Figure 4, the length of the arrow schematically indicates the flow velocity of the sealed fluid F. Also, in Figure 4, the illustration is exaggerated to clearly show that the rotating sealing ring 20 is spaced apart from the stationary sealing ring 10 in the axial direction. Furthermore, in Figure 4, the sealed fluid F is shown using shading.

[0083] As exemplified by Bernoulli's theorem, it is known that as the cross-sectional area of ​​a flow channel narrows, the flow velocity increases and the pressure decreases, while as the cross-sectional area of ​​a flow channel widens, the flow velocity decreases and the pressure increases.

[0084] As described above, the flow path cross-sectional area s1 of the first shallow groove 17 is narrower than the flow path cross-sectional area s2 of the second deep groove 16. Therefore, the flow velocity V1 of the sealed fluid F flowing through the first shallow groove 17 is faster than the flow velocity V2 of the sealed fluid F flowing through the second deep groove 16 (V1 > V2). Also, the pressure P1 of the sealed fluid F flowing through the first shallow groove 17 is lower than the pressure P2 of the sealed fluid F flowing through the second deep groove 16 (P1 < P2).

[0085] In other words, the sealed fluid F attempting to flow from the first shallow groove 17 into the bilateral connecting section 16a and the upstream connecting section 16c in the second deep groove 16 collides with the sealed fluid F in the bilateral connecting section 16a and the upstream connecting section 16c, which have a slower flow velocity and higher pressure than itself. Due to this collision, at and near the boundary between the first shallow groove 17 and the bilateral connecting section 16a and the upstream connecting section 16c, a component of the flow of the sealed fluid F is generated that is directed axially toward the sliding surface 21, resulting in positive pressure.

[0086] In particular, the sealed fluid F is more easily guided at corner 17b, so the amount of sealed fluid F flowing in per short time increases as you approach corner 17b. As a result, at the boundary between the first shallow groove 17 and the two side connecting sections 16a and the upstream side connecting section 16c, and in its vicinity, a larger positive pressure is likely to be generated as you approach corner 17b.

[0087] Furthermore, the sealed fluid F at corner 17b and its vicinity also contains a component directed downstream in the circumferential direction due to the shear force of the sliding surface 21, and is therefore supplied between the land 13 and the sliding surface 21. On the other hand, the sealed fluid F that contributes to the generation of positive pressure but is not supplied between the land 13 and the sliding surface 21 flows into the second deep groove 16.

[0088] As described above, in this embodiment, the mechanical seal generates dynamic pressure not only at the closed end 14a but also near the second deep groove 16 due to the fluid F to be sealed flowing along the shallow groove 14, thus dispersing the locations where dynamic pressure is generated. This makes it easier to keep the sliding surfaces 11 and 21 substantially parallel to each other.

[0089] Furthermore, since the shallow groove 14 is in communication with the outer space S1, which is one of the spaces, through the first deep groove 15, the efficiency of introducing the sealed fluid F from the outer space S1 is enhanced.

[0090] Furthermore, the second deep groove 16 extends in a direction that intersects the shallow groove 14. This makes it easier to guide the sealed fluid F flowing along the shallow groove 14 into the second deep groove 16, thereby increasing the efficiency of dynamic pressure generation.

[0091] Furthermore, since the shallow groove 14 has a tapered shape that narrows towards the closed end 14a, the efficiency of dynamic pressure generation at and near the closed end 14a can be increased.

[0092] Furthermore, the second deep groove 16 has a downstream connecting portion 16b whose upstream side faces the land 13. This improves the efficiency of recovering the sealed fluid F supplied between the land 13 and the sliding surface 21 from the closed end 14a and its vicinity in the adjacent upstream dynamic pressure generating mechanism 12.

[0093] Furthermore, the second deep groove 16 has an upstream connecting portion 16c whose downstream side faces the land 13. This ensures that the downstream end 17a of the first shallow groove 17 does not have a portion downstream of the upstream end 18a of the second shallow groove 18. This portion corresponds to the corner 17b in this embodiment. This makes it easier to supply fluid from the first shallow groove 17 to the land 13.

[0094] Furthermore, since the first shallow groove 17 and the second shallow groove 18 guide the sealed fluid F in different directions, the fluid can be supplied from the shallow groove 14 to a wide area of ​​the land 13.

[0095] Furthermore, because the shallow groove 14 has a spiral groove shape, it can generate dynamic pressure at different positions not only in the circumferential direction but also in the radial direction.

[0096] Furthermore, since multiple dynamic pressure generating mechanisms 12 are provided in the circumferential direction, dynamic pressure can be generated in a balanced manner in the circumferential direction.

[0097] Furthermore, in the dynamic pressure generating mechanism 12, the dimensions L1 and L2 of the second deep groove 16 are shorter than the length in the extension direction of the first shallow groove 17 and the second shallow groove 18, and are less than half of that length. This ensures sufficient volume in the first shallow groove 17 and the second shallow groove 18, allowing for efficient generation of dynamic pressure.

[0098] In this embodiment, one of the sliding surfaces is described as the sliding surface 11 of the stationary sealing ring 10, but it is not limited to this, and may also be the sliding surface 21 of the rotating sealing ring 20.

[0099] Furthermore, in this embodiment, a configuration in which a stationary sealing ring 10 having one sliding surface is applied to an inside-type mechanical seal has been illustrated, but the embodiment is not limited to this, and as illustrated as Modification 1-1 in Figure 5, it may also be applied to an outside-type mechanical seal that separates an outer space S11 where the atmosphere A is present from an inner space S12 where the fluid to be sealed F is present.

[0100] With this configuration, the dynamic pressure generating mechanism 12 can generate dynamic pressure mainly using the atmosphere A, using both the atmosphere A and the sealed fluid F, or generating dynamic pressure mainly using the sealed fluid F, depending on the amount of sealed fluid F held between the sliding surfaces 11 and 21. Each of these cases will be explained below.

[0101] When there is an abundant amount of air A between the sliding surfaces 11 and 21, the inside of the dynamic pressure generating mechanism 12 is almost completely filled with air A. As shown by the white arrows in Figure 5, the dynamic pressure generating mechanism 12 is introduced from the outside space S11, similar to the sealed fluid F in the above embodiment, and can generate dynamic pressure near the two-sided communication section 16a and the upstream communication section 16c, as well as near the closed end 14a and its vicinity, by utilizing the air A guided along the dynamic pressure generating mechanism 12.

[0102] Furthermore, when the sealed fluid F and the atmosphere A are mixed between the sliding surfaces 11 and 21, the dynamic pressure generating mechanism 12 can recover the sealed fluid F that flows between the land 13 and the sliding surface 21 and moves downstream due to the shear force of the sliding surface 21. In other words, the recovered sealed fluid F and the atmosphere A flow into the dynamic pressure generating mechanism 12. The dynamic pressure generating mechanism 12 can use the sealed fluid F and the atmosphere A guided along the dynamic pressure generating mechanism 12 to generate dynamic pressure near the two-sided communication section 16a and the upstream communication section 16c, as well as the closed end 14a and its vicinity.

[0103] Furthermore, when there is an abundant amount of the sealed fluid F between the sliding surfaces 11 and 21, the inside of the dynamic pressure generating mechanism 12 is almost completely filled with the sealed fluid F. The dynamic pressure generating mechanism 12 can generate dynamic pressure near the two-sided communication section 16a and the upstream communication section 16c, as well as near the closed end 14a, by utilizing the sealed fluid F guided along the dynamic pressure generating mechanism 12, similar to the embodiment described above.

[0104] Furthermore, the air A supplied between the sliding surfaces 11 and 21 by the dynamic pressure generating mechanism 12 may be used to push the sealed fluid F that has flowed between the sliding surfaces 11 and 21 back into the inner space S12, thereby making it less likely for the sealed fluid F to leak into the outer space S11.

[0105] Furthermore, although a mechanical seal has been described as a sliding component, a bearing may also be used. For example, as illustrated in Figure 6 as Modification 1-2, one of the sliding surfaces may be the sliding surface 111 of the stationary ring 110 in a thrust bearing. Even with such a configuration, the dynamic pressure generating mechanism 12 can introduce fluid present in the outer space S21 to generate dynamic pressure near the second deep groove 16, the closed end 14a, and its vicinity.

[0106] One of the sliding surfaces may be the sliding surface 121 of the rotating ring 120 in the thrust bearing.

[0107] Furthermore, as illustrated in Figures 6 and 7 as Modification 1-3, one of the sliding surfaces may be the inner circumferential surface 8a of the radial bearing 8.

[0108] Referring to Figure 7, the dynamic pressure generating mechanism 112 provided on the inner circumferential surface 8a has a shallow groove 114 that communicates with the space on one side of the inner circumferential surface 8a in the axial direction through a first deep groove 115, and this shallow groove is divided into a first shallow groove 117 and a second shallow groove 118 by a second deep groove 116 that intersects with the extension direction of the shallow groove 114.

[0109] As a result, the dynamic pressure generating mechanism 112 can introduce fluid present in the space on one side in the axial direction and generate dynamic pressure near the double-sided connecting portion 116a and the upstream connecting portion 116c in the second deep groove 116, as well as near the closed end 114a.

[0110] One of the sliding surfaces may be the outer circumferential surface 8b (see Figure 6) of the radial bearing 8 as a sliding component, or it may be the inner circumferential surface 8a and the outer circumferential surface 8b.

[0111] Next, the sliding parts according to Embodiment 2 will be described with reference to Figures 8 and 9. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0112] As shown in Figure 8, the stationary sealing ring 210 in Embodiment 2 is provided with a plurality of dynamic pressure generating mechanisms 212 on its sliding surface 211.

[0113] As shown in Figures 8 and 9, the dynamic pressure generating mechanism 212 has substantially the same shape as the dynamic pressure generating mechanism 12 in Embodiment 1, but inverted radially with respect to a line extending in the circumferential direction.

[0114] The dynamic pressure generating mechanism 212 has a shallow groove 214 that communicates with the internal space S2 through a first deep groove 215, and this shallow groove is divided into a first shallow groove 217 and a second shallow groove 218 by a second deep groove 216 that intersects the direction of extension of the shallow groove 214.

[0115] The dynamic pressure generating mechanism 212, similar to the modified example 1-1, can introduce air A present in the internal space S2 to generate dynamic pressure near the two-sided connecting portions 216a and the upstream connecting portion 216c in the second deep groove 216, as well as near the closed end 214a and its vicinity. The dynamic pressure generating mechanism 212 can also collect the sealed fluid F that has flowed between the land 213 and the sliding surface 21 to generate dynamic pressure near the two-sided connecting portions 216a and the upstream connecting portion 216c, as well as near the closed end 214a and its vicinity.

[0116] In addition, the internal space of the stationary sealing ring 210 in Embodiment 2 may contain the sealed fluid F, similar to the modified example 1-1. With this configuration, dynamic pressure can be generated using the sealed fluid F near the two-sided connecting portion 216a and the upstream connecting portion 216c, as well as near the closed end 214a.

[0117] As explained above, the one space is not limited to the outer space S1 described in Embodiment 1, but may also be the inner space S2.

[0118] This is also true for the thrust bearing illustrated in Modification 1-2 of Embodiment 1. In other words, the dynamic pressure generating mechanism 212 is provided on the sliding surface 111 of the stationary ring 110 and may be in communication with the internal space S22 (see Figure 6).

[0119] The same applies to the radial bearing 8 exemplified in Modification 1-3 of Embodiment 1. In other words, although not shown directly, the dynamic pressure generating mechanism 112 in Modification 1-3 may be inverted axially with respect to a line extending in the circumferential direction, and a dynamic pressure generating mechanism communicating with the space on the other side in the axial direction (see Figure 7) may be provided.

[0120] Next, the sliding parts according to Embodiment 3 will be described with reference to Figure 10. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0121] As shown in Figure 10, the stationary sealing ring 310 in Embodiment 3 is provided with a plurality of outer diameter-side dynamic pressure generating mechanisms 12 and a plurality of inner diameter-side dynamic pressure generating mechanisms 212 on its sliding surface 311.

[0122] In this embodiment, the shallow groove 14 in the outer diameter side dynamic pressure generating mechanism 12 has a depth approximately the same as the shallow groove 214 in the inner diameter side dynamic pressure generating mechanism 212, but its volume is smaller than that of the shallow groove 214. Note that the depths of the shallow groove 14 and the shallow groove 214 may be different.

[0123] Furthermore, the deep grooves 15 and 16 in the outer diameter dynamic pressure generating mechanism 12 have approximately the same depth as the deep grooves 215 and 216 in the inner diameter dynamic pressure generating mechanism 212, but their volume is smaller than that of the deep grooves 215 and 216. Note that the depths of the deep grooves 15 and 16 and the deep grooves 215 and 216 may be different.

[0124] As a result, at low speeds immediately after the rotating sealing ring 20 begins to rotate in the forward direction relative to the stationary sealing ring 310, the sliding surfaces 311 and 21 can be slightly separated by the positive pressure mainly generated by the dynamic pressure generating mechanism 12 on the outer diameter side. In addition, since the positive pressure generated by the dynamic pressure generating mechanism 212 on the inner diameter side is small at low speeds, the fluid to be sealed F can easily flow into the inner diameter side between the sliding surfaces 11 and 21 at low speeds. In other words, the sliding surfaces 311 and 21 are in a state where the frictional force due to relative sliding is reduced, mainly due to liquid lubrication.

[0125] Furthermore, when the relative rotational speed of the rotating sealing ring 20 increases further and reaches high-speed rotation, i.e., a steady-state operation, the positive pressure generated at high speed becomes greater than the positive pressure generated at low speed.

[0126] In particular, the positive pressure generated by the dynamic pressure generation mechanism 212 on the inner diameter side increases, strengthening the force that pushes the sealed fluid F back towards the outer space S1, causing air A to flow into the outer diameter side between the sliding surfaces 11 and 21. In other words, the sliding surfaces 311 and 21 are primarily lubricated by gas, and the frictional force due to relative sliding is reduced. At this time, the distance between the sliding surfaces 311 and 21 is greater than at low speeds, so the positive pressure generated by the dynamic pressure generation mechanism 12 on the outer diameter side is smaller.

[0127] As explained above, one sliding surface may be provided with a dynamic pressure generation mechanism on one side of the space and a dynamic pressure generation mechanism on the other side of the space.

[0128] Next, the sliding component according to Embodiment 4 will be described with reference to Figure 11. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0129] As shown in Figure 11, the stationary sealing ring 410 in Embodiment 4 is provided with a plurality of dynamic pressure generating mechanisms 412 on its sliding surface 411.

[0130] The dynamic pressure generating mechanism 412 has a single shallow groove 414 that communicates with the outer space S1 through a first deep groove 15, which is divided into a first shallow groove 417, a second shallow groove 418, and a third shallow groove 419 by a second deep groove 416 and a third deep groove 19 that intersect with the direction of extension of the shallow groove 414.

[0131] The third deep groove 19 has two connecting sections 19a, one on the upstream side which communicates with the first shallow groove 417 as an upstream region and the other on the downstream side which communicates with the third shallow groove 419 as a downstream region; a downstream connecting section 19b, the other on the upstream side which faces the land 413 and the other on the downstream side which communicates with the third shallow groove 419; and an upstream connecting section 19c, the other on the upstream side which communicates with the first shallow groove 417 and the other on the downstream side which faces the land 413. The downstream connecting section 19b also communicates with the second deep groove 416, which is located further downstream than itself.

[0132] Furthermore, as illustrated in Figure 12 as Modification 4-1, the dynamic pressure generating mechanism 412A may not have a downstream connecting portion 19b. In other words, multiple deep grooves, such as the second deep groove 416A and the third deep groove 19A in the dynamic pressure generating mechanism 412A, may not communicate with each other.

[0133] Returning to Figure 11, the second deep groove 416 has two side connecting sections 416a, the upstream side of which communicates with the third shallow groove 419 as an upstream region and the downstream side of which communicates with the second shallow groove 418 as a downstream region; a downstream side connecting section 416b, the upstream side of which faces the land 413 and the downstream side of which communicates with the second shallow groove 418; and an upstream side connecting section 416c, the upstream side of which communicates with the third shallow groove 419 and the downstream side of which faces the land 413.

[0134] The dynamic pressure generating mechanism 412 can generate dynamic pressure near the double-sided connecting portion 19a and the upstream connecting portion 19c in the third deep groove 19, near the double-sided connecting portion 416a and the upstream connecting portion 416c in the second deep groove 416, and near the closed end 414a and its vicinity, by the sealed fluid F flowing along the shallow groove 414.

[0135] Thus, shallow grooves only need to be divided by one or more deep grooves, and the number of divided regions may be changed as appropriate. In particular, when the surface width of the sliding surface is wide, increasing the number of divided regions is preferable in that it makes it easier to distribute the dynamic pressure.

[0136] Furthermore, since the dynamic pressure generating mechanism 412 has a downstream communication portion 19b in the third deep groove 19 and a downstream communication portion 416b in the second deep groove 416, the efficiency of recovering the sealed fluid F supplied between the land 413 and the sliding surface 421 from the closed end 414a and its vicinity in the adjacent upstream dynamic pressure generating mechanism 412 is higher than that of the dynamic pressure generating mechanism 12 in the first embodiment.

[0137] Next, the sliding parts according to Embodiment 5 will be described with reference to Figures 13 and 14. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0138] As shown in Figure 13, the stationary sealing ring 510 in Embodiment 5 is provided with a plurality of dynamic pressure generating mechanisms 512 on its sliding surface 511 (nine in this embodiment).

[0139] As shown in Figure 14, the dynamic pressure generating mechanism 512 has a shallow groove 514 that communicates with the outer space S1 through a first deep groove 515, and this shallow groove is divided into a first shallow groove 517 and a second shallow groove 518 by a second deep groove 516 that intersects its extension direction.

[0140] The second deep groove 516 has a double-sided connecting section 516a, which communicates with the first shallow groove 517 on the upstream side and with the second shallow groove 518 on the downstream side, and a downstream-side connecting section 516b, which faces the land 513 on the upstream side and communicates with the second shallow groove 518 on the downstream side.

[0141] The dynamic pressure generating mechanism 512 can generate dynamic pressure near the two-sided connecting portion 516a and the closed end 514a and its vicinity in the second deep groove 516 by the sealed fluid F flowing along the shallow groove 514.

[0142] Furthermore, since the dynamic pressure generating mechanism 512 has a downstream communication portion 516b in the second deep groove 516, the efficiency of recovering the sealed fluid F supplied between the land 513 and the sliding surface 21 from the closed end 514a and its vicinity in the adjacent upstream dynamic pressure generating mechanism 512 is improved. On the other hand, from the viewpoint of easily supplying fluid from the first shallow groove 17 to the land 13, the dynamic pressure generating mechanism 12 of the above embodiment 1 is preferable.

[0143] Furthermore, the second shallow groove 518 in Example 5 is wider and has a longer circumference than the second shallow groove 18 in Example 1, making it easier to generate positive pressure even at low rotational speeds, thus providing a configuration suitable for low speeds.

[0144] Next, the sliding parts according to Embodiment 6 will be described with reference to Figure 15. Note that descriptions of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0145] As shown in Figure 15, the dynamic pressure generating mechanism 612 of the stationary sealing ring 610 in Embodiment 6 includes a communication groove 615 and two grooves 617 and 618 that become shallower toward the downstream side. The communication groove 615 is the first deep groove 15 of Embodiment 1.

[0146] Groove 617 is located upstream of groove 618 and is connected to groove 618.

[0147] More specifically, the upstream groove 617 communicates with the downstream end of the communication groove 615. The bottom surface 617d of groove 617 extends from the downstream end of the bottom surface 615a of the communication groove 615 toward the downstream groove 618 and axially toward the rotating sealing ring 20. Furthermore, the downstream end edge of the bottom surface 617d of groove 617 is continuous with the axially extending side surface 612f.

[0148] The deepest part of the groove 617 is the portion where the upstream edge of the bottom surface 617d of the groove 617 is located, that is, the corner portion with the bottom surfaces 617d and 615a, and its depth is approximately the same as that of the first deep groove 15 in Embodiment 1. However, the deepest part of the groove 617 may have a different depth from that of the first deep groove 15 in Embodiment 1.

[0149] The shallowest part of groove 617 is the portion where the downstream edge of the bottom surface 617d of groove 617 is located, that is, the corner portion between the bottom surface 617d and the side surface 612f, and its depth is approximately the same as that of the shallow groove 14 in Embodiment 1. In other words, the downstream side of the upstream groove 617 and the upstream side of the downstream groove 618 are in direct communication. Note that the shallowest part of groove 617 may have a different depth from that of the shallow groove 14 in Embodiment 1.

[0150] The downstream groove 618, like the second shallow groove 18 in Embodiment 1, has a tapered shape that narrows towards the closed end 618b located downstream when viewed from the axial direction. The bottom surface 618d of the groove 618 extends inclined from the deeper end in the axial direction on the side surface 612f toward the closed end 618b and toward the rotating sealing ring 20 in the axial direction. The downstream edge of the bottom surface 618d of the groove 618 is continuous with the land 613.

[0151] The deepest part of groove 618 is the portion where the upstream edge of the bottom surface 618d of groove 618 is located, that is, the corner portion formed by the bottom surface 618d and the side surface 612f, and its depth is approximately the same as that of the second deep groove 16 in Embodiment 1. However, the deepest part of groove 618 may have a different depth than the second deep groove 16 in Embodiment 1. Furthermore, it is preferable that the deepest parts of groove 617 and groove 618 have the same depth, but they may be different.

[0152] Even with a dynamic pressure generating mechanism 612 configured in this way, dynamic pressure can be generated not only at the closed end 618b of the downstream groove 618 and its vicinity, but also near the connection point between the upstream groove 617 and the downstream groove 618, similar to the dynamic pressure generating mechanism 12 of Embodiment 1. In other words, the dynamic pressure generating mechanism 612 can distribute the locations where dynamic pressure is generated.

[0153] Furthermore, the depth of the grooves 617 and 618 gradually decreases towards the downstream side. As a result, the dynamic pressure generating mechanism 612 is more efficient at generating dynamic pressure at the closed end 618b of the downstream groove 618 and its vicinity, as well as near the connection point between the upstream groove 617 and the downstream groove 618.

[0154] The number of grooves constituting the dynamic pressure generation mechanism may be changed as appropriate, as long as there are two or more grooves. Increasing the number of grooves allows for an increase in the number of locations where dynamic pressure is generated by a single dynamic pressure generation mechanism.

[0155] Furthermore, the bottom surface 618d of the downstream groove 618 in this embodiment has a shape like a negative linear function when the intersection of the bottom surface 618d and the side surface 612f is considered as the origin, the side surface 612f as the Y-axis, and the direction perpendicular to it in the plane of the paper as the X-axis. However, it is not limited to this, and a curved shape, such as a quadratic function, exponential function, or logarithmic function, is also acceptable. On the other hand, a shape like a negative linear function or logarithmic function is preferred from the viewpoint that the depth decreases rapidly towards the closed end, making it easier to generate positive pressure at and near the closed end. The same applies to the upstream groove 617.

[0156] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0157] For example, in the above embodiments 1 to 5, the shallow groove was described as having a spiral groove shape, but it is not limited to this. It may also be a linearly extending inclined groove, a groove extending only in the circumferential direction, a wide groove, or a groove of constant width. Any groove shape that can generate dynamic pressure may be appropriately modified.

[0158] Furthermore, although the shallow groove has been described as being in communication with one space through a connecting section, it is not limited to this configuration, and may not be in communication with either space. Even with such a configuration, fluid can be drawn in from one space by the relative negative pressure generated on the upstream side. On the other hand, from the viewpoint of efficiently generating dynamic pressure, it is preferable to have a connecting section.

[0159] Furthermore, although the shallow groove may be in direct communication with one of the spaces, it is preferable to have a connecting section from the viewpoint of efficiently generating dynamic pressure.

[0160] Furthermore, while embodiments 1 to 5 illustrate structures in which the deep groove extends in a direction intersecting the shallow groove, the invention is not limited to this. For example, the deep groove does not have to extend in a direction intersecting the shallow groove, as is the case with the second deep groove 716A of the dynamic pressure generating mechanism 712A in the stationary sealing ring 710A illustrated as modified example 7-1 in Figure 16. In other words, it does not have to extend from one side to the other located in the direction in which the shallow grooves intersect. Also, as with the shallow groove 714A, a part of the first shallow groove 717A and a part of the second shallow groove 718A may be in direct communication. In short, the shallow groove only needs to have an upstream region on the relative rotation upstream side of the deep groove and a downstream region on the relative rotation downstream side of the deep groove.

[0161] Furthermore, from the viewpoint of easily generating dynamic pressure, it is preferable that the deep groove be formed on the downstream side in the upstream region, as in the second deep groove 716A, and it is even more preferable that it has an upstream communication section.

[0162] Furthermore, although the depth of the first shallow groove was described as being approximately constant in the above embodiments 1 to 5, it is not limited to this, and may become shallower toward the second deep groove 716B, as shown in Figure 17 as modified example 7-2 of the first shallow groove 717B of the dynamic pressure generating mechanism 712B in the stationary sealing ring 710B. With such a configuration, the efficiency of generating dynamic pressure near the second deep groove can be increased.

[0163] Similarly, the depth of the second shallow groove may be shallower in the direction away from the second deep groove 716B, that is, toward the closed end 714a, as in the second shallow groove 718B of the dynamic pressure generating mechanism 712B. With such a configuration, the efficiency of generating dynamic pressure at and near the closed end can be increased.

[0164] Furthermore, although it was explained in Examples 1 to 5 that the deep groove has a portion that communicates only with the downstream region, this is not limited to this, and it is not necessary to have a portion that communicates only with the downstream region. On the other hand, from the viewpoint of contributing to the smooth generation of dynamic pressure by storing the recovered fluid, a structure in which a portion that communicates only with the downstream region is provided is preferable.

[0165] Furthermore, the fluid used for lubrication may be a liquid or a gas, or it may be a mist mixture of liquid and gas.

[0166] 1 Rotating shaft 4 Housing 11 Sliding surface (one sliding surface) 14 Shallow groove 14a Closed end 15 First deep groove (communicating section) 16 Second deep groove (deep groove) 16a Both side communicating sections 16b Downstream communicating section 16c Upstream communicating section 17 First shallow groove (upstream region) 18 Second shallow groove (downstream region) 21 Sliding surface (the other sliding surface) S1 Outer space (one space) S2 Inner space (the other space)

Claims

1. A sliding component in which a pair of sliding surfaces are arranged at a location where they rotate relative to each other, and at least one of the sliding surfaces is provided with a dynamic pressure generating mechanism, wherein the dynamic pressure generating mechanism comprises a shallow groove having a closed end that extends downstream of the relative rotation and is closed, and at least one deep groove intersecting the direction of extension of the shallow groove, wherein the shallow groove has an upstream region on the upstream side of the relative rotation of the deep groove and a downstream region on the downstream side of the relative rotation of the deep groove.

2. The sliding component according to claim 1, wherein the dynamic pressure generating mechanism communicates with the one space and has a communication portion that is deeper than the shallow groove.

3. The sliding component according to claim 1, wherein the deep groove extends across both sides of the shallow groove.

4. The sliding component according to claim 1, wherein the shallow groove has a tapered shape that narrows towards the closed end.

5. The sliding part according to claim 1, wherein the deep groove has at least two communicating portions, the upstream side of relative rotation communicating with the upstream region and the downstream side of relative rotation communicating with the downstream region, and the downstream side communicating with the land, and the downstream side communicating with the downstream region.

6. The sliding part according to claim 1, wherein the deep groove has at least two communicating portions, the upstream side of relative rotation communicating with the upstream region and the downstream side of relative rotation communicating with the downstream region, and an upstream communicating portion, the upstream side of relative rotation communicating with the upstream region and the downstream side of relative rotation facing a land.

7. The sliding component according to claim 1, wherein the extension direction is different between the side surface on the downstream side of the relative rotation of the upstream region and the side surface on the downstream side of the relative rotation of the downstream region.

8. The sliding component according to claim 1, wherein the shallow groove extends inclined from one space to the other space.

9. The sliding component according to any one of claims 1 to 8, wherein the dynamic pressure generating mechanism is provided in multiple locations in the circumferential direction.

10. A sliding component in which a pair of sliding surfaces are arranged at a location where they rotate relative to each other, and at least one of the sliding surfaces is equipped with a dynamic pressure generating mechanism, wherein the dynamic pressure generating mechanism has a plurality of interconnected grooves that become shallower toward the downstream side of the relative rotation, and the groove located furthest downstream has a closed end that is closed toward the downstream side of the relative rotation.

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