Sliding parts

Abstract

To provide a sliding component having high lubrication performance.SOLUTION: At least one sliding surface 11 includes: an outer-diameter side dynamic pressure generation mechanism 12 having an outer-diameter side circulation groove 121 and an outer-diameter side dynamic pressure groove 122b formed on an outer-diameter side with respect to the outer-diameter side circulation groove 121 and surrounded by an outer-diameter side space S1 and the outer-diameter side circulation groove 121; and an inner-diameter side dynamic pressure generation mechanism 13 having an inner-diameter side circulation groove 131 located on an inner-diameter side with respect to the outer-diameter side circulation groove 121, and an inner-diameter dynamic pressure groove 132b arranged on an inner-diameter side with respect to the inner-diameter side circulation groove 131 and surrounded by an inner-diameter side space S2 and the inner-diameter side circulation groove 131. The outer-diameter side dynamic pressure generation mechanism 12 and the inner-diameter side dynamic pressure generation mechanism 13 are arranged on top of with each other in a circumferential direction .SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to sliding parts, for example, sliding parts used for shaft seals and bearings.

Background Art

[0002] As a sliding part for preventing leakage of a fluid to be sealed around a rotating shaft in a rotating machine, for example, a mechanical seal including 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 measures and the like, and some sliding surfaces of the sliding rings are provided with dynamic pressure generating grooves.

[0003] For example, on the sliding surface of one sliding ring of the mechanical seal shown in Patent Document 1, a first negative pressure generating groove and a dynamic pressure generating groove are provided on the inner diameter side, and a second negative pressure generating groove is provided on the outer diameter side. The first negative pressure generating groove is partitioned by an annular land so as to be non-communicating with the second fluid space on the outer diameter side, and the second negative pressure generating groove is partitioned by an annular land so as to be non-communicating with the first fluid space on the inner diameter side. The dynamic pressure generating groove is disposed on the inner diameter side of the first negative pressure generating groove. Also, a first circumferential groove is formed between the first negative pressure generating groove and the second negative pressure generating groove, and another circumferential groove is formed between the first negative pressure generating groove and the dynamic pressure generating groove.

[0004] When the pair of sliding rings rotate relative to each other in the forward direction, dynamic pressure is generated at the closed end of the dynamic pressure generating groove by the first fluid on the inner diameter side, so that the sliding surfaces are slightly separated from each other, and the lubricity between the sliding surfaces is improved. Further, the first fluid flowing out from the closed end of the dynamic pressure generating groove between the sliding surfaces is sucked in by the first negative pressure generating groove and discharged to another circumferential groove. Furthermore, the second fluid flowing into the space between the sliding surfaces from the second fluid space on the outer diameter side due to the separation of the sliding surfaces is sucked in by the second negative pressure generating groove and returned to the second fluid space. Thereby, while ensuring the lubricity between the sliding surfaces, it is possible to prevent the first fluid from flowing into the second fluid space or the second fluid from flowing into the first fluid space.

Prior Art Documents

[0005] [Patent Document 1] International Publication No. 2018 / 092742 (page 11, Figure 3) [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the mechanical seal described in Patent Document 1, the first fluid is collected in one circumferential groove and the second fluid in the other circumferential groove, thereby suppressing the mixing of the first and second fluids. However, there was a risk that the area between the first and second circumferential grooves on the sliding surface, i.e., the radial center of the sliding surface, would suffer from poor lubrication.

[0007] This invention was made in view of these problems, and aims to provide sliding parts with high lubricity. [Means for solving the problem]

[0008] To solve the aforementioned problems, the sliding component of the present invention is A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space, At least one of the sliding surfaces is An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove, The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove. The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are in the circumferential direction From Arranged in overlapping positions Occasionally, The outer diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the outer diameter side dynamic pressure groove is in communication with the circumferential portion. The inner diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the inner diameter side dynamic pressure groove communicates with the circumferential portion. Yes, they are. According to this, the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism can be ensured to be large in the radial direction, and the lands located on the inner diameter side of the outer diameter side dynamic pressure generating mechanism and the lands located on the outer diameter side of the inner diameter side dynamic pressure generating mechanism can be made smaller. Therefore, the lubricity can be enhanced across the radial direction on the sliding surface.

[0009] To solve the aforementioned problems, the sliding component of the present invention is A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space, At least one of the sliding surfaces is An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove, The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove. The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged to overlap when viewed from the circumferential direction. A sliding component having an annular groove extending in the circumferential direction formed between the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism. According to this, the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism can be ensured to be large in the radial direction, and the lands located on the inner diameter side of the outer diameter side dynamic pressure generating mechanism and the lands located on the outer diameter side of the inner diameter side dynamic pressure generating mechanism can be made smaller. Therefore, the lubricity can be enhanced across the radial direction on the sliding surface.

Brief Description of the Drawings

[0016] [Figure 1] It is a longitudinal sectional view showing an example of a mechanical seal in Example 1 of the present invention. [Figure 2] It is a view of the sliding surface of the stationary seal ring in Example 1 as seen from the axial direction. [Figure 3] It is an enlarged view of the main part of FIG. 2. [Figure 4] It is a view of the sliding surface of the stationary seal ring when the rotating seal ring rotates forward as seen from the axial direction. [Figure 5] It is a view of the sliding surface of the stationary seal ring when the rotating seal ring rotates backward as seen from the axial direction. [Figure 6] It is a view of the sliding surface of the stationary seal ring in Example 2 of the present invention as seen from the axial direction. [Figure 7] It is a view showing a modified example of the sliding surface of the stationary seal ring in Example 1 of the present invention.

Modes for Carrying Out the Invention

[0017] A mode for implementing the sliding part according to the present invention will be described below based on an embodiment.

Embodiment

[0018] The sliding part according to Embodiment 1 will be described with reference to FIGS. 1 to 5. In this embodiment, a mechanical seal is taken as an example of the sliding part for description. In this mechanical seal of the present embodiment, a first fluid F1 such as oil exists in an outer space S1 as an outer diameter side space, and a second fluid F2 such as water exists in an inner space S2 as an inner diameter side space. Also, for convenience of explanation, dots may be added to grooves or the like formed on the sliding surface in the drawings.

[0019] The mechanical seal shown in FIG. 1 is an inside type that seals the first fluid F1 that tends to leak from the outer diameter side to the inner diameter side of the sliding surface. That is, an example in which the first fluid F1 is at a higher pressure than the second fluid F2 will be described.

[0020] The mechanical seal is mainly composed of a stationary seal ring 10 and a rotating seal ring 20. The stationary seal ring 10 has an annular shape and is provided in a non-rotating state and axially movable state on a seal cover 5 fixed to a housing 4 of the device to be attached. The rotating seal ring 20 has an annular shape and is provided in a state of being rotatable together with the rotating shaft 1 via a sleeve 2 on the rotating shaft 1. The stationary seal ring 10 is axially biased by an elastic member 7. The sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotating seal ring 20 are in close sliding contact with each other. Note that the sliding surface 21 of the rotating seal ring 20 is a flat surface, and no recesses such as grooves are provided on this flat surface.

[0021] 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 above-mentioned sliding materials, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc., are also applicable.

[0022] 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 and in a clockwise direction as indicated by the dashed arrow. Hereafter, the direction of the solid arrow will be described as the forward rotation direction of the rotating sealing ring 20, and the direction of the dashed arrow will be described as the reverse rotation direction of the rotating sealing ring 20.

[0023] Multiple (four of each in this embodiment) outer diameter side dynamic pressure generating mechanisms 12 and inner diameter side dynamic pressure generating mechanisms 13 are provided on the sliding surface 11 of the stationary sealing ring 10. These outer diameter side dynamic pressure generating mechanisms 12 and inner diameter side dynamic pressure generating mechanisms 13 are arranged alternately at circumferential intervals on the sliding surface 11, or in other words, they overlap when viewed from the circumferential direction.

[0024] First, the outer diameter side dynamic pressure generation mechanism 12 will be described. As shown in Figure 3, the outer diameter side dynamic pressure generation mechanism 12 comprises a first outer diameter side circulation groove 121 as an outer diameter side circulation groove, an outer diameter side dynamic pressure generation element 122, a second outer diameter side circulation groove 123, and a specific dynamic pressure generation element 124 as a dynamic pressure generation element.

[0025] The first outer diameter side circulation groove 121 is composed of a first portion 121a as a circumferential portion, a second portion 121b, and a third portion 121c. As will be described in detail later, the second portion 121b functions as an outlet portion during forward rotation and an inlet portion during reverse rotation. On the other hand, the third portion 121c functions as an inlet portion during forward rotation and an outlet portion during reverse rotation.

[0026] The first portion 121a extends in the circumferential direction and is positioned on the inner diameter side of the imaginary line α passing through the radial center of the sliding surface 11.

[0027] The second portion 121b extends outward from one end of the first portion 121a, that is, the downstream end of relative rotation during forward rotation, and communicates with the outer space S1. In an axial view, the second portion 121b extends linearly outward from one end of the first portion 121a, while being inclined toward the downstream side of relative rotation.

[0028] The third portion 121c extends outward from the other end of the first portion 121a, that is, the upstream end of relative rotation during forward rotation, and communicates with the outer space S1. In an axial view, this third portion 121c extends linearly outward from the other end of the first portion 121a, while being inclined toward the upstream side of relative rotation.

[0029] The first outer diameter circulation groove 121 has a symmetrical shape with respect to a virtual line β that extends radially and passes through the circumferential center of the first portion 121a.

[0030] The outer diameter side dynamic pressure generating element 122 is formed in a region enclosed radially and circumferentially by the first outer diameter side circulation groove 121 and the outer space S1. The outer diameter side dynamic pressure generating element 122 includes a communication groove portion 122a, an outer diameter side dynamic pressure groove 122b, and an outer diameter side reverse dynamic pressure groove 122c.

[0031] The communication groove 122a is provided along the circumferential center of the first portion 121a in the first outer diameter side circulation groove 121 and communicates with the first portion 121a.

[0032] The outer diameter side dynamic pressure groove 122b extends outward from one end of the communication groove 122a, i.e., the downstream end of the relative rotation during forward rotation, while inclined toward the downstream side of the relative rotation, and then extends further circumferentially toward the downstream side of the relative rotation. In other words, the outer diameter side dynamic pressure groove 122b extends from one end of the communication groove 122a in an approximately inverted L shape when viewed from the axial direction.

[0033] The outer diameter reverse dynamic pressure groove 122c extends outward from the other end of the communication groove 122a, i.e., the end on the relative rotation upstream side during forward rotation, while inclined toward the relative rotation upstream side, and then extends further circumferentially toward the relative rotation upstream side. In other words, the outer diameter reverse dynamic pressure groove 122c extends from the other end of the communication groove 122a in an approximately L-shape when viewed from the axial direction.

[0034] The outer diameter side dynamic pressure generating element 122 has a symmetrical shape with respect to the imaginary line β.

[0035] The second outer diameter side circulation groove 123 is located on the outer diameter side of the outer diameter side dynamic pressure generating element 122 in the region enclosed in the radial and circumferential directions by the first outer diameter side circulation groove 121 and the outer space S1 on the sliding surface 11.

[0036] The second outer diameter side circulation groove 123 is composed of a first portion 123a, a second portion 123b, and a third portion 123c. The first portion 123a is parallel to the first portion 121a of the first outer diameter side circulation groove 121.

[0037] The second portion 123b extends outward from one end of the first portion 123a, communicates with the outer space S1, and is parallel to the second portion 123b of the first outer diameter side circulation groove 121.

[0038] The third portion 123c extends outward from the other end of the first portion 123a, communicates with the outer space S1, and is parallel to the third portion 121c of the first outer diameter side circulation groove 121.

[0039] The specific dynamic pressure generating element 124 is provided in a region enclosed in the radial and circumferential directions by the second outer diameter side circulation groove 123 and the outer space S1 on the sliding surface 11. The specific dynamic pressure generating element 124 comprises a radial groove 124a communicating with the outer space S1, and Rayleigh steps 124b and 124c extending from the inner diameter end of the radial groove 124a to both sides in the circumferential direction. The radial groove 124a is formed to the same depth as the Rayleigh steps 124b and 124c, but they may be formed to different depths.

[0040] In this embodiment, the first outer diameter side circulation groove 121 and the second outer diameter side circulation groove 123 are formed to the same depth, and are formed deeper than the outer diameter side dynamic pressure generating element 122 and the specific dynamic pressure generating element 124. However, the first outer diameter side circulation groove 121 and the second outer diameter side circulation groove 123 may be formed to different depths, as long as they are formed deeper than the outer diameter side dynamic pressure generating element 122 and the specific dynamic pressure generating element 124. Furthermore, the outer diameter side dynamic pressure generating element 122 and the specific dynamic pressure generating element 124 may be of the same depth or of different depths.

[0041] Next, the inner diameter side dynamic pressure generation mechanism 13 will be described. As shown in Figure 3, the inner diameter side dynamic pressure generation mechanism 13 comprises a first inner diameter side circulation groove 131 as an inner diameter side circulation groove, an inner diameter side dynamic pressure generation element 132, a second inner diameter side circulation groove 133, and a specific dynamic pressure generation element 134 as a dynamic pressure generation element.

[0042] The first inner diameter side circulation groove 131 is composed of a first portion 131a as a circumferential portion, a second portion 131b, and a third portion 131c. As will be described in detail later, the second portion 131b functions as an outlet portion during forward rotation and an inlet portion during reverse rotation. On the other hand, the third portion 131c functions as an inlet portion during forward rotation and an outlet portion during reverse rotation.

[0043] The first portion 131a extends in the circumferential direction and is positioned on the outer diameter side of the imaginary line α passing through the radial center of the sliding surface 11.

[0044] The second portion 131b extends inward from one end of the first portion 131a, that is, the downstream end of the relative rotation during forward rotation, and communicates with the internal space S2. In an axial view, the second portion 131b extends linearly inward from one end of the first portion 131a, while being inclined toward the downstream side of the relative rotation.

[0045] The third portion 131c extends inward from the other end of the first portion 131a, that is, the upstream end of relative rotation during forward rotation, and communicates with the internal space S2. In an axial view, this third portion 131c extends linearly inward from the other end of the first portion 131a, while being inclined toward the upstream side of relative rotation.

[0046] The first inner diameter circulation groove 131 has a symmetrical shape with respect to a virtual line β' that extends radially and passes through the circumferential center of the first portion 131a.

[0047] The inner diameter side dynamic pressure generating element 132 is formed in a region enclosed in the radial and circumferential directions by the first inner diameter side circulation groove 131 and the inner space S2. The inner diameter side dynamic pressure generating element 132 includes a communication groove portion 132a, an inner diameter side dynamic pressure groove 132b, and an inner diameter side reverse dynamic pressure groove 132c.

[0048] The communication groove 132a is provided along the circumferential center of the first portion 131a in the first inner diameter side circulation groove 131 and communicates with the first portion 131a.

[0049] The inner diameter side dynamic pressure groove 132b extends inward from one end of the communication groove 132a, that is, the downstream end of the relative rotation during forward rotation, while inclined toward the downstream side of the relative rotation, and then extends further circumferentially toward the downstream side of the relative rotation. In other words, the inner diameter side dynamic pressure groove 132b extends in a substantially L-shape in axial view from one end of the communication groove 132a.

[0050] The inner diameter reverse dynamic pressure groove 132c extends inward from the other end of the communication groove 132a, i.e., the end on the relative rotation upstream side during forward rotation, while inclined toward the relative rotation upstream side, and then extends further circumferentially toward the relative rotation upstream side. In other words, the inner diameter reverse dynamic pressure groove 132c extends from the other end of the communication groove 122a in an approximately inverted L shape when viewed from the axial direction.

[0051] The inner diameter side dynamic pressure generating element 132 has a symmetrical shape with respect to the imaginary line β'.

[0052] The second inner diameter side circulation groove 133 is located on the inner diameter side of the inner diameter side dynamic pressure generating element 132 in the region enclosed in the radial and circumferential directions by the first inner diameter side circulation groove 131 and the inner space S2 on the sliding surface 11.

[0053] The second inner diameter side circulation groove 133 is composed of a first portion 133a, a second portion 133b, and a third portion 133c. The first portion 133a is parallel to the first portion 131a of the first inner diameter side circulation groove 131.

[0054] The second portion 133b extends outward from one end of the first portion 133a, communicates with the inner space S2, and is parallel to the second portion 133b of the first inner diameter side circulation groove 131.

[0055] The third portion 133c extends outward from the other end of the first portion 133a, communicates with the inner space S2, and is parallel to the third portion 131c of the first inner diameter side circulation groove 131.

[0056] The specific dynamic pressure generating element 134 is provided in the region enclosed in the radial and circumferential directions by the second inner diameter side circulation groove 133 and the inner space S2 on the sliding surface 11. The specific dynamic pressure generating element 134 comprises a radial groove 134a communicating with the inner space S2, and Rayleigh steps 134b and 134c extending from the outer diameter end of the radial groove 134a in both circumferential directions. The radial groove 134a is formed to the same depth as the Rayleigh steps 134b and 134c, but they may be formed to different depths.

[0057] In this embodiment, the first inner diameter side circulation groove 131 and the second inner diameter side circulation groove 133 are formed to the same depth, and are formed deeper than the inner diameter side dynamic pressure generating element 132 and the specific dynamic pressure generating element 134. However, the first inner diameter side circulation groove 131 and the second inner diameter side circulation groove 133 may be formed to different depths, as long as they are formed deeper than the inner diameter side dynamic pressure generating element 132 and the specific dynamic pressure generating element 134. Furthermore, the inner diameter side dynamic pressure generating element 132 and the specific dynamic pressure generating element 134 may be of the same depth or of different depths.

[0058] Next, the flow of the first fluid F1 and the second fluid F2 during the relative rotation of the stationary sealing ring 10 and the rotating sealing ring 20 will be described in general terms with reference to Figures 4 and 5. Note that the relative rotational speed of the stationary sealing ring 10 and the rotating sealing ring 20 will not be specified in this explanation.

[0059] First, when the rotating sealing ring 20 is stopped and not rotating, the first fluid F1 flows into each groove of the outer diameter side dynamic pressure generating mechanism 12, and the second fluid F2 flows into each groove of the inner diameter side dynamic pressure generating mechanism 13.

[0060] Furthermore, when not rotating, the sliding surfaces 11 and 21 are in contact with each other, and the first fluid F1 and the second fluid F2 are hardly mixed between the sliding surfaces 11 and 21.

[0061] Next, we will describe the state in which the rotating sealing ring 20 is rotated relative to the stationary sealing ring 10 in the positive direction.

[0062] As shown in Figure 4, when the rotating sealing ring 20 rotates relative to the stationary sealing ring 10 in the positive direction, the first fluid F1 and the second fluid F2 move within each groove in accordance with the rotational direction of the stationary sealing ring 10.

[0063] Specifically, in the specific dynamic pressure generating elements 124 and 134, the first fluid F1 and the second fluid F2 move to the closed ends 124d and 134d of the Rayleigh steps 124b and 134b, and positive pressure is generated at and near the closed ends 124d and 134d. The force caused by the positive pressure generated at and near the closed ends 124d and 134d of the Rayleigh steps 124b and 134b separates the sliding surfaces 11 and 21 from each other, thereby improving lubrication and suppressing wear between the sliding surfaces 11 and 21.

[0064] Furthermore, at the opposite Rayleigh steps 124c and 134c, the first fluid F1 and the second fluid F2 move from the closed ends 124e and 134e to the radial grooves 124a and 134a, generating a relative negative pressure at and near the closed ends 124e and 134e. Consequently, the relative negative pressure generated at and near the closed ends 124e and 134e of the Rayleigh steps 124c and 134c draws in the surrounding first fluid F1 and second fluid F2. Note that the relative negative pressure referred to here is not a vacuum, but rather a pressure lower than the surrounding pressure.

[0065] The first fluid F1 and the second fluid F2 that flow out from the closed ends 124d, 134d of the Rayleigh steps 124b, 134b between the sliding surfaces 11, 21 are recovered by the second outer diameter side circulation groove 123 and the second inner diameter side circulation groove 133 and returned to the outer space S1 and the inner space S2.

[0066] In the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132, positive pressure is generated at the closed ends 122d, 132d and their vicinity on the downstream side of relative rotation, while relative negative pressure is generated at the closed ends 122e, 132e and their vicinity on the upstream side of relative rotation.

[0067] Since the first fluid F1 and the second fluid F2 are taken in from the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131 into the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132, poor lubrication is suppressed.

[0068] Furthermore, the first fluid F1 and the second fluid F2 that flow out between the sliding surfaces 11 and 21 from the closed ends 122d, 132d and their vicinity of the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132 are recovered by the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131, or the second outer diameter side circulation groove 123 and the second inner diameter side circulation groove 133, and returned to the outer space S1 and the inner space S2.

[0069] The dynamic pressure generated at the closed ends 122d, 132d and near the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132, and the dynamic pressure generated at the closed ends 124d, 134d and near the Rayleigh steps 124b, 134b, are prevented from interfering with each other by the second outer diameter side circulation groove 123 and the second inner diameter side circulation groove 133.

[0070] Next, we will describe the state in which the rotating sealing ring 20 rotates relative to the stationary sealing ring 10 in the opposite direction.

[0071] As shown in Figure 5, when the rotating sealing ring 20 rotates relative to the stationary sealing ring 10 in the opposite direction, the first fluid F1 and the second fluid F2 move within each groove in accordance with the rotational direction of the stationary sealing ring 10.

[0072] Specifically, in the specific dynamic pressure generating elements 124 and 134, the first fluid F1 and the second fluid F2 move to the closed ends 124e and 134e of the Rayleigh steps 124c and 134c, and positive pressure is generated at and near the closed ends 124e and 134e.

[0073] Furthermore, at the opposite Rayleigh steps 124b and 134b, relative negative pressure is generated at the closed ends 124d and 134d and their vicinity.

[0074] The first fluid F1 and the second fluid F2 that flow out from the closed ends 124e and 134e of the Rayleigh steps 124c and 134c between the sliding surfaces 11 and 21 are recovered by the second outer diameter side circulation groove 123 and the second inner diameter side circulation groove 133 and returned to the outer space S1 and the inner space S2.

[0075] Furthermore, in the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132, positive pressure is generated at the closed ends 122e, 132e on the downstream side of relative rotation and in their vicinity, while relative negative pressure is generated at the closed ends 122d, 132d on the upstream side of relative rotation and in their vicinity.

[0076] Since the first fluid F1 and the second fluid F2 are taken in from the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131 into the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132, poor lubrication is suppressed.

[0077] Furthermore, the first fluid F1 and the second fluid F2 that flow out between the sliding surfaces 11 and 21 from the closed ends 122e, 132e and their vicinity of the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132 are recovered by the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131, or the second outer diameter side circulation groove 123 and the second inner diameter side circulation groove 133, and returned to the outer space S1 and the inner space S2.

[0078] The dynamic pressure generated at the closed ends 122e, 132e of the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132, and the dynamic pressure generated at the closed ends 124e, 134e of the Rayleigh steps 124b, 134b, and their vicinity, are prevented from interfering with each other by the second outer diameter side circulation groove 123 and the second inner diameter side circulation groove 133.

[0079] As explained above, the first fluid F1 and the second fluid F2 that flow out from the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132 between the sliding surfaces 11 and 21 are mainly recovered by the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131 and returned to the outer space S1 and inner space S2, thus preventing mixing.

[0080] In other words, the region between the first outer diameter circulation groove 121 and the second outer diameter circulation groove 123 is lubricated by the dynamic pressure from the outer diameter dynamic pressure groove 122b, and the region between the first inner diameter circulation groove 131 and the second inner diameter circulation groove 133 is lubricated by the dynamic pressure from the inner diameter dynamic pressure groove 132b. The dynamic pressure from the circumferentially adjacent outer diameter dynamic pressure groove 122b and the dynamic pressure from the inner diameter dynamic pressure groove 132b are prevented from interfering with each other by the first outer diameter circulation groove 121 and the first inner diameter circulation groove 131, respectively, and the fluid is recovered, thus suppressing the mixing of fluids in each region.

[0081] Furthermore, the space between the second outer diameter circulation groove 123 and the outer diameter end of the sliding surface 11, and the space between the second inner diameter circulation groove 133 and the inner diameter end of the sliding surface 11 are lubricated by specific dynamic pressure generating elements 124 and 134. However, if the specific dynamic pressure generating elements 124 and 134, the second outer diameter circulation groove 123, and the second inner diameter circulation groove 133 are absent, the outer diameter dynamic pressure groove 122b can lubricate up to the outer diameter end, and the inner diameter dynamic pressure groove 132b can lubricate up to the inner diameter end, respectively.

[0082] Furthermore, since the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 are offset in the circumferential direction and overlap in the circumferential direction, a large radial area can be secured for the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 on the sliding surface 11, and the land 111 located on the inner diameter side of the outer diameter side dynamic pressure generating mechanism 12 and the land 112 located on the outer diameter side of the inner diameter side dynamic pressure generating mechanism 13 can be made smaller. As a result, lubrication can be improved along the radial direction of the sliding surface 11.

[0083] Specifically, the outer diameter side dynamic pressure generation mechanism 12 can improve lubricity using the first fluid F1, and the inner diameter side dynamic pressure generation mechanism 13 can improve lubricity using the second fluid F2.

[0084] Furthermore, the dynamic pressure generated by the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 causes the sliding surfaces 11 and 21 to separate, thereby supplying the second fluid F2 to the land 111 from the inner space S2 and the first fluid F1 to the land 112 from the outer space S1, further enhancing lubrication.

[0085] Furthermore, the second fluid F2 supplied to land 111 and the first fluid F1 supplied to land 112 move more circumferentially due to the rotating sealing ring 20 than radially due to fluid pressure. Therefore, the second fluid F2 is less likely to flow into the first outer diameter side circulation groove 121, and the first fluid F1 is less likely to flow into the first inner diameter side circulation groove 131.

[0086] Furthermore, the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 are arranged alternately in the circumferential direction. This arrangement ensures that the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 are well-balanced in the circumferential direction of the sliding surface 11, eliminating any areas that are always poorly lubricated in the radial direction when viewed in the circumferential direction, thus making the lubrication in the circumferential direction nearly uniform.

[0087] Furthermore, referring to Figure 3, the first outer diameter side circulation groove 121 is positioned on the inner diameter side of the imaginary line α, and the first inner diameter side circulation groove 131 is positioned on the outer diameter side of the imaginary line α. This allows for a larger radial region between the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13, thereby improving lubrication by the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13.

[0088] Furthermore, referring to Figures 4 and 5, the adjacent first outer diameter side circulation groove 121 has its second portion 121b and third portion 121c extending from both sides of the first portion 121a, inclined away from the circumferential direction, and the first inner diameter side circulation groove 131 has its second portion 131b and third portion 131c extending from both sides of the first portion 131a, inclined away from the circumferential direction. As a result, the closed end 122d of the outer diameter side dynamic pressure groove 122b and the closed end 132e of the inner diameter side dynamic pressure groove 132b can be spaced apart in the circumferential direction by the amount of the circumferentially adjacent second portion 121b and third portion 131c. Also, the closed end 132d of the inner diameter side dynamic pressure groove 132b and the closed end 122e of the outer diameter side dynamic pressure groove 122b can be spaced apart in the circumferential direction by the amount of the circumferentially adjacent second portion 131b and second portion 131b. This prevents the fluid that flows out between the sliding surfaces 11 and 21 from mixing.

[0089] Furthermore, the second portion 121b and the third portion 121c of the first outer diameter side circulation groove 121 communicate with the outer space S1, and the second portion 131b of the first inner diameter side circulation groove 131 communicate with the inner space S2. As a result, during relative rotation, fluid always flows through the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131, and this flow allows the first fluid F1 recovered in the first outer diameter side circulation groove 121 to be returned to the outer space S1, and the second fluid F2 recovered in the first inner diameter side circulation groove 131 to be returned to the inner space S2, so that the fluids do not easily mix.

[0090] Furthermore, the angles formed by the first part 121a and the second part 121b, the angles formed by the first part 121a and the third part 121c, the angles formed by the first part 131a and the second part 131b, and the angles formed by the first part 131a and the third part 131c are obtuse angles, so fluid flows smoothly between the first part 121a and the second part 121b and the third part 121c, and between the first part 131a and the second part 131b and the third part 131c.

[0091] Furthermore, the outer diameter side dynamic pressure generating mechanism 12 is equipped with an outer diameter side dynamic pressure groove 122b and an outer diameter side reverse dynamic pressure groove 122c, and the inner diameter side dynamic pressure generating mechanism 13 is equipped with an inner diameter side dynamic pressure groove 132b and an inner diameter side reverse dynamic pressure groove 132c. As a result, regardless of the rotation direction of the rotating sealing ring 20, dynamic pressure can be generated in the dynamic pressure generating groove on one side, and fluid can be recovered in the dynamic pressure generating groove on the opposite side.

[0092] Furthermore, since the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132 are in communication with the first portion 121a of the first outer diameter side circulation groove 121 and the first portion 131a of the first inner diameter side circulation groove 131, fluid can be reliably introduced into the outer diameter side dynamic pressure generating element 122 and the inner diameter side dynamic pressure generating element 132.

[0093] Furthermore, since the outer diameter side dynamic pressure generating mechanism 12 has a specific dynamic pressure generating element 124 that communicates with the outer space S1, and the inner diameter side dynamic pressure generating mechanism 13 has a specific dynamic pressure generating element 134 that communicates with the inner space S2, the levitation effect between the sliding surfaces 11 and 21 can be enhanced, thereby improving lubrication. [Examples]

[0094] Next, the sliding parts according to Example 2 will be described with reference to Figure 6. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0095] In this embodiment 2, the sliding surface 211 of the stationary sealing ring 210 is provided with an annular deep groove 214 that divides the region on the outer diameter side of the dynamic pressure generating mechanism 212 from the region on the inner diameter side of the dynamic pressure generating mechanism 213.

[0096] This annular deep groove 214 comprises a first portion 214a, a second portion 214b, and a third portion 214c.

[0097] The first part 214a extends along the land 111. The second part 214b extends along the land 112. The third part 214c extends along the land 113 between the circumferentially adjacent outer diameter side dynamic pressure generating mechanism 212 and inner diameter side dynamic pressure generating mechanism 213, and connects the first part 214a and the second part 214b.

[0098] According to this, the annular deep groove 214 can recover the first fluid F1 moving from the outer space S1 to the inner space S2 and the second fluid F2 moving from the inner space S2 to the outer space S1, thereby preventing the inflow of the first fluid F1 into the inner space S2 and the inflow of the second fluid F2 into the outer space S1.

[0099] Furthermore, in this embodiment 2, since there is one annular deep groove 214, a region prone to poor lubrication is not formed, unlike in the conventional configuration where two annular deep grooves are provided in the radial direction.

[0100] In this embodiment 2, a configuration with one annular deep groove 214 is illustrated, but multiple grooves may be provided. Even in this case, the land 111 on the inner diameter side is smaller than the outer diameter side dynamic pressure generating mechanism 212, and the land 112 on the outer diameter side is smaller than the inner diameter side dynamic pressure generating mechanism, thus improving lubrication compared to the conventional configuration. Furthermore, from the viewpoint of two-liquid separation, it is preferable to provide an even number of annular deep grooves.

[0101] 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.

[0102] For example, in the above embodiments 1 and 2, an example was given in which the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism have radially symmetrical shapes, but they may also have asymmetrical shapes.

[0103] Furthermore, while embodiments 1 and 2 illustrate a configuration in which the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are alternately provided in the circumferential direction, they do not necessarily have to be alternate in the circumferential direction.

[0104] Furthermore, in the above embodiments 1 and 2, the configuration is not limited to one in which multiple outer diameter side dynamic pressure generating mechanisms and multiple inner diameter side dynamic pressure generating mechanisms are provided; as long as at least one is provided, the number of each can be freely changed.

[0105] Furthermore, while embodiments 1 and 2 described above illustrate configurations in which the outer diameter side dynamic pressure generating mechanism is positioned on the inner diameter side of the radial center of the sliding surface, and the inner diameter side dynamic pressure generating mechanism is positioned on the outer diameter side of the radial center of the sliding surface, it is sufficient that the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism overlap in the circumferential direction. For example, one dynamic pressure generating mechanism does not need to extend radially to the opposite side of the radial center of the sliding surface, and the other dynamic pressure generating mechanism does not need to extend radially to the opposite side of the radial center of the sliding surface.

[0106] Furthermore, while embodiments 1 and 2 described above illustrate a configuration in which the outer diameter side circulation groove and the inner diameter side circulation groove communicate with the outer diameter side space and the inner diameter side space, one end may not communicate, or both ends may not communicate. Even in this case of non-communication, the outer diameter side dynamic pressure generation mechanism can be said to be surrounded by the outer diameter side circulation groove and the outer space S1. The same applies to the inner diameter side dynamic pressure generation mechanism.

[0107] Furthermore, in the above-described embodiments 1 and 2, the outer diameter side dynamic pressure groove and the inner diameter side dynamic pressure groove were shown to be in communication with the outer diameter side circulation groove and the inner diameter side circulation groove, respectively. However, they may not be in communication with the outer diameter side circulation groove and the inner diameter side circulation groove as long as it is possible to introduce fluid from the outer diameter side space and the inner diameter side space.

[0108] Furthermore, the outer diameter and inner diameter dynamic pressure grooves are not limited to the shapes of Embodiments 1 and 2, but may also be Rayleigh steps, spiral grooves, etc., and can be freely changed. It is also possible to have a structure in which multiple dynamic pressure grooves are connected to or located close to a single lubrication groove.

[0109] Furthermore, while embodiments 1 and 2 illustrate a configuration in which the outer diameter circulation groove and the inner diameter circulation groove form a roughly trapezoidal shape in axial view, the invention is not limited to this configuration and can be freely modified to, for example, a roughly triangular shape or a roughly arc shape in axial view.

[0110] Furthermore, while embodiments 1 and 2 above illustrate configurations in which a second outer diameter side circulation groove and a second inner diameter side circulation groove are provided, these configurations may be omitted. In this case, the outer diameter side dynamic pressure groove and the inner diameter side dynamic pressure groove may be in direct communication with the outer diameter side space and the inner diameter side space. In addition, the configurations of the second outer diameter side circulation groove and the second inner diameter side circulation groove may be omitted, as may the configurations of the specific dynamic pressure generating elements on the inner diameter side and outer diameter side.

[0111] Furthermore, while embodiments 1 and 2 above illustrate configurations in which the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are compatible with both rotational and unidirectional rotation, they may also be compatible with only unidirectional rotation.

[0112] For example, it may be a configuration that supports unidirectional rotation as shown in Figure 7. The sliding surface 311 of the stationary sealing ring 310 is provided with four outer diameter side dynamic pressure generating mechanisms 312 and four inner diameter side dynamic pressure generating mechanisms 313. The outer diameter side dynamic pressure generating mechanism 312 consists of an outer diameter side circulation groove 321 and an outer diameter side dynamic pressure generating element 322. The inner diameter side dynamic pressure generating mechanism 313 consists of an inner diameter side circulation groove 331 and an inner diameter side dynamic pressure generating element 332.

[0113] The outer diameter side dynamic pressure generating element 322 is composed of a portion extending outward from the first portion 321a of the outer diameter side circulation groove 321, and a portion extending downstream from the outer diameter end of said portion in the relative rotation direction in the positive rotation direction, forming a substantially inverted L shape.

[0114] The inner diameter side dynamic pressure generating element 332 is substantially L-shaped and consists of a portion extending inward from the first portion 331a of the inner diameter side circulation groove 331 and a portion extending downstream in the relative rotation direction in the positive rotation direction from the inner diameter end of said portion.

[0115] Furthermore, while mechanical seals were used as an example of sliding parts in Examples 1 and 2 above, other mechanical seals such as those used in general industrial machinery, automobiles, and water pumps may also be used. Moreover, the invention is not limited to mechanical seals, but may also use sliding parts other than mechanical seals, such as sliding bearings. [Explanation of symbols]

[0116] 1. Axis of rotation 4 Housing 10 Stationary sealing ring 11 Sliding surface 12. Outer diameter side dynamic pressure generation mechanism 13. Inner diameter side dynamic pressure generation mechanism 20 Rotating Sealing Rings 21 Sliding surface 111-113 Land 121 1st outer diameter side circulation groove (outer diameter side circulation groove) 121a 1st part (circumferential part) 121b Part 2 (Introduction, Derivation) 121c Part 3 (Introduction, Derivation) 122 Outer diameter side dynamic pressure generating element 122b Outer diameter side dynamic pressure groove 122c Reverse dynamic pressure groove on outer diameter side 124 Specific Dynamic Pressure Generating Elements (Dynamic Pressure Generating Elements) 131 1st inner diameter side circulation groove (inner diameter side circulation groove) 131a 1st part (circumferential part) 131b Part 2 (Introduction, Derivation) 131c Part 3 (Introduction, Derivation) 132 Inner diameter side dynamic pressure generating element 132b Inner diameter side dynamic pressure generating groove 132c Inner diameter side reverse dynamic pressure groove 134 Specific Dynamic Pressure Generating Elements (Dynamic Pressure Generating Elements) F1 1st fluid F2 2nd fluid S1 outer space (outer diameter side space) S2 Inner space (inner diameter side space)

Claims

1. A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space, At least one of the sliding surfaces is An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove, The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove. The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged to overlap when viewed from the circumferential direction. The outer diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the outer diameter side dynamic pressure groove is in communication with the circumferential portion. The inner diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the inner diameter side dynamic pressure groove is in communication with the circumferential portion, making it a sliding component.

2. A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space, At least one of the sliding surfaces is An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove, The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove. The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged to overlap when viewed from the circumferential direction. A sliding component having an annular groove extending in the circumferential direction formed between the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism.

3. The sliding component according to claim 1 or 2, wherein the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged alternately in the circumferential direction.

4. The sliding component according to claim 1 or 2, wherein the outer diameter side dynamic pressure generating mechanism extends beyond the radial center of the sliding surface to the inner diameter side, and the inner diameter side dynamic pressure generating mechanism extends beyond the radial center of the sliding surface to the outer diameter side.

5. At least one of the ends of the outer diameter side circulation groove communicates with the outer diameter side space, The sliding part according to claim 1 or 2, wherein at least one of the ends of the inner diameter side circulation groove is in communication with the inner diameter side space.

6. The outer diameter side dynamic pressure generating mechanism has an outer diameter side reverse dynamic pressure groove extending in the circumferential direction opposite to the outer diameter side dynamic pressure groove, The sliding component according to claim 1 or 2, wherein the inner diameter side dynamic pressure generating mechanism has an inner diameter side reverse dynamic pressure groove extending in the circumferential direction opposite to the inner diameter side dynamic pressure groove.

7. The sliding component according to claim 1 or 2, wherein at least one of the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism is provided with a dynamic pressure generating element that communicates with the outer diameter side space or the inner diameter side space.

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