Sliding parts

Abstract

Provided is a sliding component in which sliding surfaces can smoothly slide against each other from a low-speed state to a high-speed state, regardless of whether the relative rotation direction is the forward rotation direction or the reverse rotation direction.　The sliding component has deep grooves 17 that section the component into a fluid-side region A1 in which fluid-side grooves 13 and fluid-side reverse grooves 14 are provided, and leak-side regions A2 in which leak-side grooves 15a-15c and leak-side reverse grooves 16a-16c are provided.

Description

Technical Field

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

Background Art

[0002] As a sliding part for preventing leakage of a sealed fluid around a 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 measures and the like, and there are some in which dynamic pressure generating grooves are provided on the sliding surfaces of the sliding rings.

[0003] For example, the mechanical seal shown in Patent Document 1 has a plurality of spiral grooves on the inner diameter side and a plurality of spiral grooves on the outer diameter side provided on the sliding surface of one of the sliding rings. The spiral grooves on the inner diameter side communicate with the space on the leakage side, which is the inner diameter side of the sliding surface, and extend in the outer diameter direction while inclining in one circumferential direction. Further, the spiral grooves on the outer diameter side communicate with the space on the sealed fluid side, which is the outer diameter side of the sliding surface, and extend in the inner diameter direction while inclining in the other circumferential direction. Since the spiral grooves extend in the radial direction while inclining in the circumferential direction, a higher dynamic pressure generating ability can be obtained compared to concave portions and grooves such as dimples and Rayleigh steps extending along the radial direction.

[0004] When the relative rotation speed of the sliding rings is low, the sealed fluid flows into the space between the sliding surfaces from the spiral grooves on the outer diameter side, and a liquid film is formed. Further, when the relative rotation speed of the sliding rings is high, the gas on the leakage side is sucked in from the start end portion on the inner diameter side of the spiral grooves on the inner diameter side, and dynamic pressure is generated at the end portion, so that the sliding surfaces are slightly separated from each other, and the lubricity between the sliding surfaces is improved. Further, when the relative rotation speed of the sliding rings is high, the spiral grooves on the outer diameter side suck in the sealed fluid between the sliding surfaces and discharge it to the outer diameter side, so that leakage of the sealed fluid into the space on the leakage side is suppressed.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] International Publication No. 2018 / 051867 (page 10, Figure 2) [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Depending on the type of rotating machinery, the direction of rotation may be switched depending on the situation, and a mechanical seal that can accommodate the relative rotation direction of both sliding rings was desired. However, mechanical seals such as those in Patent Document 1 can be used at low speeds when the relative rotation of the sliding rings is in the opposite direction, but they cannot be used at high speeds, and therefore cannot accommodate both relative rotation directions of the sliding rings from low speed to high speed.

[0007] This invention addresses these problems and aims to provide a sliding component that allows sliding surfaces to slide smoothly against each other from low speed to high speed, regardless of whether the relative rotation direction is forward or reverse. [Means for solving the problem]

[0008] To solve the aforementioned problems, the sliding component of the present invention is A sliding component having a pair of sliding surfaces that are positioned opposite each other at points that rotate relative to each other when a rotating machine is driven, and which separate a fluid-side space from a leakage-side space, On one of the sliding surfaces, A fluid side groove that communicates with the aforementioned fluid side space and extends in the positive direction of relative rotation, A fluid-side reverse groove that communicates with the fluid-side space and extends in the opposite direction of relative rotation, A leak groove having at least one end positioned on the leak-side space side of the fluid-side groove and the fluid-side reverse groove, and extending from that end toward the fluid-side space in the relative rotational positive direction, At least one end of the leak-side reverse groove is positioned on the leak-side space side of the fluid-side groove and the fluid-side reverse groove, and the leak-side reverse groove extends from that end toward the fluid-side space in the opposite direction of relative rotation, The system includes a deep groove that separates the fluid-side region where the fluid-side groove and the fluid-side reverse groove are provided from the leak-side region where the leak-side groove and the leak-side reverse groove are provided. According to this, when the relative rotation of the sliding parts is in the forward direction at a low speed, the lubrication between the sliding surfaces is improved mainly by the sealed fluid supplied between the sliding surfaces from the closed end of the fluid channel. When the relative rotation is in the forward direction at a high speed, the sealed fluid supplied between the sliding surfaces from the fluid channel is collected in the deep groove, thus suppressing positive pressure in the fluid channel. Furthermore, when the relative rotation is in the reverse direction at a low speed, the lubrication between the sliding surfaces is improved mainly by the sealed fluid supplied between the sliding surfaces from the closed end of the reverse fluid channel. When the reverse rotation is at a high speed, the sealed fluid supplied between the sliding surfaces from the reverse fluid channel is collected in the deep groove, thus suppressing positive pressure in the reverse fluid channel. In addition, the fluid that flows into the sliding surfaces from the closed end of one fluid channel or reverse fluid channel is collected by the other fluid channel or reverse fluid channel and the deep groove, so the suction function of the leak channel or leak reverse channel prevents the sealed fluid from leaking into the leak side space.

[0009] The deep groove may be in communication with the fluid-side space. According to this, fluid enters and exits the deep groove from the fluid-side space, thus stabilizing the amount of sealed fluid within the deep groove.

[0010] The leak-side ends of the leak-side groove and the leak-side reverse groove may be in communication with the leak-side space. According to this, when there is relative rotation in the forward direction, the leaking fluid can be efficiently introduced from the leaking space to the leaking groove, and when there is relative rotation in the reverse direction, the leaking fluid can be efficiently introduced from the leaking space to the reverse leaking groove.

[0011] The sliding surface may be provided with a communication groove that connects the respective leak-side ends of the leak-side groove and the reverse leak-side groove. According to this, when the relative rotation is in the forward direction, the fluid recovered in the leak-side reverse groove can be guided to the leak-side groove through the connecting groove, and when the relative rotation is in the reverse direction, the fluid recovered in the leak-side groove can be guided to the leak-side reverse groove through the connecting groove.

[0012] The aforementioned connecting groove may be annular. According to this design, fluid drawn into the leak side groove or leak side reverse groove can be recovered in the annular connecting groove, and the fluid in the annular connecting groove can be guided to the leak side groove or leak side reverse groove. Furthermore, since a land is formed on the leak side of the annular deep groove, the fluid recovered in the connecting groove is less likely to leak into the leak side space.

[0013] The end portions of the leakage channel and the leakage reverse channel may be positioned on the fluid side of the space than the end portions of the fluid channel and the fluid reverse channel. This ensures that the length of each groove is sufficiently maintained.

[0014] The fluid side groove, the leak side reverse groove, the fluid side reverse groove, and the leak side groove are arranged at an inclination. The deep groove may have a first inclined portion extending along the fluid side groove and the leak side reverse groove, and a second inclined portion extending along the fluid side reverse groove and the leak side groove. According to this, a first inclined section can be placed between the fluid side groove and the leak side reverse groove, and a second inclined section can be placed between the fluid side reverse groove and the leak side groove, allowing multiple grooves to be efficiently arranged in the circumferential direction. [Brief explanation of the drawing]

[0015] [Figure 1] This is a longitudinal cross-sectional view showing an example of a mechanical seal in Embodiment 1 of the present invention. [Figure 2] This is a view of the sliding surface of the stationary sealing ring in Example 1, seen from the axial direction. [Figure 3] This is an enlarged view from the axial direction of the sliding surface of the stationary sealing ring when the rotating sealing ring is rotating at a low forward speed in Example 1. [Figure 4] This is an enlarged view from the axial direction of the sliding surface of the stationary sealing ring when the rotating sealing ring is rotating at high speed in the forward direction in Example 1. [Figure 5] This is a view of the sliding surface of the stationary sealing ring in Embodiment 2 of the present invention, as seen from the axial direction. [Figure 6]This is a view of the sliding surface of the stationary seal ring in Example 3 of the present invention as seen axially. [Figure 7] This is a view of the sliding surface of the stationary seal ring in Example 4 of the present invention as seen axially. [Figure 8] This is a view of the sliding surface of the stationary seal ring in Example 5 of the present invention as seen axially. [Figure 9] This is a schematic view showing a modified example of the fluid-side groove and the fluid-side reverse groove.

Embodiments for Carrying Out the Invention

[0016] Embodiments for implementing the sliding parts according to the present invention will be described below based on examples.

Examples

[0017] The sliding parts according to Example 1 will be described with reference to FIGS. 1 to 4. In this example, a mechanical seal will be described as an example of the sliding parts. In this example of the mechanical seal, the atmosphere A exists in the inner space S1, and the sealed fluid F exists in the outer space S2. The inner diameter side of the sliding ring constituting the mechanical seal will be described as the leakage side (low pressure side), and the outer diameter side will be described as the sealed fluid side (high pressure side). Also, for convenience of explanation, dots may be added to grooves and the like formed on the sliding surface in the drawings.

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

[0019] The mechanical seal mainly consists of a stationary sealing ring 10 and a rotating sealing ring 20. The stationary sealing ring 10 is annular in shape and is provided on a seal cover 5 fixed to the housing 4 of the equipment to be mounted, in a non-rotatable state and movable in the axial direction. The rotating sealing ring 20 is annular in shape and is provided on a rotating shaft 1 via a sleeve 2 so as to be rotatable with the rotating shaft 1. The stationary sealing ring 10 is biased in the axial direction by an elastic member 7, so that the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 slide in close contact with each other. The sliding surface 21 of the rotating sealing ring 20 is a flat surface, and there are no grooves or other recesses on this flat surface.

[0020] 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.

[0021] As shown in Figure 2, the rotating sealing ring 20, which is the mating sealing ring, slides relative to the stationary sealing ring 10 in a clockwise direction as indicated by the solid arrow, or in a counterclockwise 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.

[0022] The sliding surface 11 of the stationary sealing ring 10 is provided with a plurality of fluid-side spiral grooves 13 as fluid-side grooves, a plurality of fluid-side reverse spiral grooves 14 as fluid-side reverse grooves, a plurality of leak-side spiral grooves 15a to 15c as leak-side grooves, a plurality of leak-side reverse spiral grooves 16a to 16c as leak-side reverse grooves, and a plurality of deep grooves 17. Hereinafter, a spiral groove is defined as a groove whose extending direction has both a radial component and a circumferential component.

[0023] Multiple fluid-side spiral grooves 13 are arranged circumferentially on the outer diameter side of the sliding surface 11 (three in this embodiment). The outer diameter end 13A of the fluid-side spiral groove 13 communicates with the outer space S2, and extends in the forward rotation direction of the rotating sealing ring 20, i.e., in the circumferential direction, with respect to the point of communication.

[0024] More specifically, the fluid-side spiral groove 13 is a spiral groove that extends in an arc shape, inclined with a clockwise component from the outer diameter side to the inner diameter side. Furthermore, the inner diameter end 13B of the fluid-side spiral groove 13 has a closed shape, i.e., it is a closed end. This fluid-side spiral groove 13 has a constant depth in the direction of extension.

[0025] Multiple fluid-side reverse spiral grooves 14 are arranged circumferentially on the outer diameter side of the sliding surface 11 (three in this embodiment). The outer diameter end 14A of the fluid-side reverse spiral groove 14 communicates with the outer space S2, and extends in the reverse rotation direction of the rotating sealing ring 20, i.e., in the circumferential direction, with respect to the point of communication.

[0026] More specifically, the fluid-side reverse spiral groove 14 is a spiral groove that extends in an arc shape, inclined with a counterclockwise component from the outer diameter side to the inner diameter side. Furthermore, the inner diameter end 14B of the fluid-side reverse spiral groove 14 is closed, i.e., it is a closed end. This fluid-side reverse spiral groove 14 has a constant depth in the direction of extension. In this embodiment, the fluid-side spiral groove 13 and the fluid-side reverse spiral groove 14 have the same depth. In other words, the fluid-side reverse spiral groove 14 has a circumferentially symmetrical shape with respect to the fluid-side spiral groove 13.

[0027] Multiple leak-side spiral grooves 15a to 15c are arranged circumferentially on the inner diameter side of the sliding surface 11 (three grooves in each of these embodiments). The leak-side ends 15A of the leak-side spiral grooves 15a to 15c communicate with the inner space S1, and extend in the forward rotation direction of the rotating sealing ring 20, i.e., in the circumferential direction, relative to the point of communication. The leak-side spiral grooves 15a to 15c extend approximately parallel to the fluid-side spiral groove 13.

[0028] More specifically, the leak-side spiral grooves 15a to 15c are spiral grooves that extend in an arc shape, inclined with a clockwise component from the inner diameter side to the outer diameter side. Furthermore, the outer diameter end 15B of the leak-side spiral grooves 15a to 15c is closed, i.e., a closed end. These leak-side spiral grooves 15a to 15c have a constant depth in the direction of extension.

[0029] Furthermore, the three leak-side spiral grooves 15a to 15c are of different lengths. Leak-side spiral groove 15a is longer than leak-side spiral groove 15b, and leak-side spiral groove 15b is longer than leak-side spiral groove 15c. The ends 15B of each leak-side spiral groove 15a to 15c are arranged radially.

[0030] Furthermore, each end 15B of the leak-side spiral grooves 15a to 15c is positioned on the outer diameter side of the end 13B of the fluid-side spiral groove 13 and the end 14B of the fluid-side reverse spiral groove 14.

[0031] Multiple leak-side reverse spiral grooves 16a to 16c are arranged circumferentially on the inner diameter side of the sliding surface 11 (three grooves in each embodiment). The leak-side ends 16A of the leak-side reverse spiral grooves 16a to 16c communicate with the inner space S1, and extend in the opposite direction of rotation of the rotating sealing ring 20, i.e., in the circumferential direction, relative to the point of communication. The leak-side reverse spiral grooves 16a to 16c extend approximately parallel to the fluid-side reverse spiral groove 14.

[0032] More specifically, the leak-side reverse spiral grooves 16a to 16c are spiral grooves that extend in an arc shape, inclined with a counterclockwise component from the inner diameter side to the outer diameter side. Furthermore, the outer diameter end 16B of the leak-side reverse spiral grooves 16a to 16c is closed, i.e., it is a closed end. In other words, the leak-side reverse spiral grooves 16a to 16c are circumferentially symmetrical with the leak-side spiral grooves 15a to 15c.

[0033] These leak-side reverse spiral grooves 16a to 16c have a constant depth in the extension direction. In this embodiment, the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c are of the same depth, and the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c are formed deeper than the fluid-side spiral groove 13 and the fluid-side reverse spiral groove 14. Furthermore, the volume of the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c is larger than the volume of the fluid-side spiral groove 13 and the fluid-side reverse spiral groove 14.

[0034] The leak-side reverse spiral grooves 16a to 16c are of different lengths. Leak-side reverse spiral groove 16a is longer than leak-side reverse spiral groove 16b, and leak-side reverse spiral groove 16b is longer than leak-side reverse spiral groove 16c. The ends 16B of each of the leak-side reverse spiral grooves 16a to 16c are arranged radially.

[0035] Furthermore, each end 16B of the leak-side reverse spiral grooves 16a to 16c is positioned on the outer diameter side of the end 13B of the fluid-side spiral groove 13 and the end 14B of the fluid-side reverse spiral groove 14.

[0036] In the following explanation, the fluid-side spiral groove 13 and the fluid-side reverse spiral groove 14, which face each other so that their ends 13B and 14B approach each other in the circumferential direction, are considered as one set, and the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c, which face each other in the circumferential direction, are considered as one set.

[0037] One set of leak-side spiral grooves 15a-15c and one set of leak-side reverse spiral grooves 16a-16c are arranged in the circumferential direction between one set of fluid-side spiral grooves 13 and another adjacent set of fluid-side reverse spiral grooves 14.

[0038] Multiple deep grooves (three in this embodiment) are arranged circumferentially on the sliding surface 11. These deep grooves 17 have a constant depth in the extension direction. The deep grooves 17 are formed to be deeper than the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c. The depth of the deep grooves 17 is such that almost no dynamic pressure is generated by the relative rotation between the stationary sealing ring 10 and the rotating sealing ring 20.

[0039] The deep groove 17 has circumferential ends 17A and 17B that communicate with the outer space S2 and extends to surround a pair of fluid-side spiral grooves 13 and fluid-side reverse spiral grooves 14. More specifically, the deep groove 17 has a first inclined portion 171, a second inclined portion 172, and a third portion 173. The first portion 171 is a portion that extends approximately parallel to the fluid-side spiral groove 13 and the leak-side reverse spiral grooves 16a to 16c. The second portion 172 is a portion that extends approximately parallel to the fluid-side reverse spiral groove 14 and the leak-side spiral grooves 15a to 15c. The third portion 173 extends concentrically with the stationary sealing ring 10 and is a portion that connects the inner diameter ends of the first portion 171 and the second portion 172.

[0040] Furthermore, the portions of the sliding surface 11 other than the fluid-side spiral groove 13, the fluid-side reverse spiral groove 14, the leak-side spiral grooves 15a-15c, the leak-side reverse spiral grooves 16a-16c, and the deep groove 17 are lands 12 having flat surfaces arranged on the same plane. These flat surfaces of the lands 12 function as sliding surfaces that substantially slide against the sliding surface 21 of the rotating sealing ring 20.

[0041] The sliding surface 11 is divided into a fluid-side region A1 and a leakage-side region A2 by deep grooves 17. The fluid-side region A1 is provided with a pair of fluid-side spiral grooves 13 and fluid-side reverse spiral grooves 14, and lands 12 that separate them. The leakage-side region A2 is provided with all of the leakage-side spiral grooves 15a to 15c and leakage-side reverse spiral grooves 16a to 16c, and lands 12 that separate them. In other words, the leakage-side region A2 is the region of the sliding surface 11 other than the fluid-side region A1.

[0042] Next, the flow of the sealed fluid F and the atmosphere A 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 Figure 2. Note that the relative rotational speeds of the stationary sealing ring 10 and the rotating sealing ring 20 will not be specified in this explanation.

[0043] When the rotating sealing ring 20 rotates relative to the stationary sealing ring 10 in the positive direction, the sealed fluid F moves to the end 13B in the fluid-side spiral groove 13, generating positive pressure at and near the end 13B. In the fluid-side reverse spiral groove 14, the sealed fluid F moves to the end 14A, generating relative negative pressure at and near the end 14B. In the leak-side spiral grooves 15a to 15c, air A moves to each end 15B, generating positive pressure at and near each end 15B. In the leak-side reverse spiral grooves 16a to 16c, air A moves to each end 16A, generating relative negative pressure at and near each end 16B. Note that the relative negative pressure referred to here is not a vacuum, but a state where the pressure is lower than the ambient pressure.

[0044] On the other hand, when the rotating sealing ring 20 rotates relative to the stationary sealing ring 10 in the opposite direction, the sealed fluid F moves to end 13A in the fluid-side spiral groove 13, generating a relative negative pressure at end 13B and its vicinity. Also, in the fluid-side reverse spiral groove 14, the sealed fluid F moves to end 14B, generating a positive pressure at end 14B and its vicinity. Furthermore, in the leak-side spiral grooves 15a to 15c, air A moves to each end 15A, generating a relative negative pressure at each end 15B and its vicinity. Also, in the leak-side reverse spiral grooves 16a to 16c, air A moves to each end 16B, generating a positive pressure at each end 16B and its vicinity.

[0045] Next, the change in the force separating the sliding surfaces 11 and 21 will be explained with reference to Figures 3 and 4. Note that here, the explanation will be given using the case where the rotating sealing ring 20 rotates in the forward direction as an example, and the explanation for the case where the rotating sealing ring 20 rotates in the reverse direction will be omitted. Also, in Figures 3 and 4, for the sake of explanation, the range of positive pressure generated in each spiral groove is enclosed by a dashed line.

[0046] First, when the rotating sealing ring 20 is stopped and not rotating, the sealed fluid F flows into the fluid-side spiral groove 13 and the fluid-side reverse spiral groove 14 from the openings at ends 13A and 14A. Also, the sealed fluid F flows into the deep groove 17 from the openings at ends 17A and 17B. In addition, air A flows into the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c from the openings at ends 15A and 16A. Furthermore, since the stationary sealing ring 10 is biased toward the rotating sealing ring 20 by the elastic member 7, the sliding surfaces 11 and 21 are in contact with each other, and the amount of sealed fluid F leaking between the sliding surfaces 11 and 21 into the internal space S1 is almost zero.

[0047] At low speeds immediately after the rotating sealing ring 20 begins to rotate relative to the stationary sealing ring 10, positive pressure is generated at the end 13B of the fluid-side spiral groove 13 and at the ends 15B of the leak-side spiral grooves 15a to 15c, as shown in Figure 3. This positive pressure causes a slight separation between the sliding surfaces 11 and 21.

[0048] More specifically, the fluid-side spiral groove 13 contains a sealed fluid F with a higher pressure than the atmospheric air A flowing into the leak-side spiral grooves 15a to 15c. Furthermore, the fluid-side spiral groove 13 has a smaller capacity than the leak-side spiral grooves 15a to 15c. Therefore, the first force due to the positive pressure generated at the end 13B of the fluid-side spiral groove 13 is greater than the second force due to the positive pressure generated at each end 15B of the leak-side spiral grooves 15a to 15c. Consequently, during low-speed rotation of the rotating sealing ring 20, the first force is the dominant force causing the sliding surfaces 11 and 21 to separate from each other.

[0049] In this way, the sealed fluid F is supplied between the sliding surfaces 11 and 21 from the fluid-side spiral groove 13, and the sliding surfaces 11 and 21 are slightly separated, which improves lubrication even at low rotational speeds and suppresses wear between the sliding surfaces 11 and 21.

[0050] Furthermore, the sealed fluid F supplied to the fluid-side region A1 on the sliding surface 11 is mainly drawn into the fluid-side reverse spiral groove 14 as indicated by arrow H1, and a portion is recovered in the deep groove 17 as indicated by arrow H2. Also, since the floating distance between the sliding surfaces 11 and 21 is small, almost no sealed fluid F flows into the leak-side region A2 on the sliding surface 11. Therefore, leakage of the sealed fluid F into the inner space S1 is suppressed. When more sealed fluid F is recovered than the amount that can be stored in the deep groove 17, the excess sealed fluid F is returned to the outer space S2.

[0051] As the relative rotational speed of the rotating sealing ring 20 increases, the positive pressure generated at the end 13B of the fluid-side spiral groove 13 and the ends 15B of the leak-side spiral grooves 15a to 15c gradually increases, as shown in Figure 4. As a result, the first and second forces increase, and the sliding surfaces 11 and 21 are further separated compared to the state shown in Figure 3.

[0052] Furthermore, when the relative rotational speed of the rotating sealing ring 20 exceeds a certain level, as indicated by arrow H3, a portion of the sealed fluid F supplied from the end 13B of the fluid-side spiral groove 13 between the sliding surfaces 11 and 21 is recovered into the deep groove 17. Therefore, the first force due to the positive pressure generated at the end 13B of the fluid-side spiral groove 13 does not increase any further.

[0053] 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 amount of air A drawn into the leak-side spiral grooves 15a to 15c increases further, generating a high positive pressure, increasing the second force, and causing the sliding surfaces 11 and 21 to separate more widely.

[0054] In this embodiment, as the levitation distance increases due to the high-speed rotation of the rotating sealing ring 20, the positive pressure generated in the fluid-side spiral groove 13 becomes negligibly small. Therefore, when the rotating sealing ring 20 rotates at high speed, the second force becomes the main force that separates the sliding surfaces 11 and 21 from each other.

[0055] Furthermore, in the steady-state operation of the mechanical seal, the negative pressure generated at each end 16B of the leak-side reverse spiral grooves 16a to 16c and in their vicinity is relatively small, and the positive pressure generated at each end 15B of the opposing leak-side spiral grooves 15a to 15c acts to push most of the sealed fluid F flowing in from the outer diameter side of the leak-side region A2 into the outer space S2.

[0056] Thus, when the relative rotation of the mechanical seal is in the forward direction at a low speed, the lubrication between the sliding surfaces 11 and 21 is improved mainly by the sealed fluid F supplied between the sliding surfaces 11 and 21 from the end 13B of the fluid-side spiral groove 13. Furthermore, when the relative rotation of the mechanical seal is in the forward direction at a high speed, the sealed fluid F supplied between the sliding surfaces 11 and 21 from the fluid-side spiral groove 13 is collected in the deep groove 17, so the positive pressure in the fluid-side spiral groove 13 is suppressed, and the sliding surfaces 11 and 21 are separated by the positive pressure mainly generated at the end 15B of the leak-side spiral grooves 15a to 15c, thereby improving lubrication.

[0057] Furthermore, the sealed fluid F that flows from the end 13B of the fluid-side spiral groove 13 between the sliding surfaces 11 and 21 is collected by the fluid-side reverse spiral groove 14 and the deep groove 17. Therefore, the suction function of the leak-side reverse spiral grooves 16a to 16c prevents the sealed fluid F from leaking into the internal space S1.

[0058] Furthermore, the sliding surface 11 is provided with a fluid-side reverse spiral groove 14 that is circumferentially symmetrical to the fluid-side spiral groove 13, and leak-side reverse spiral grooves 16a to 16c that are circumferentially symmetrical to the leak-side spiral grooves 15a to 15c. Therefore, when the relative rotation of the mechanical seal is in the reverse direction, it performs the same function as described above.

[0059] Furthermore, since the deep groove 17 is in communication with the outer space S2, the sealed fluid F can be moved in and out between the deep groove 17 and the outer space S2, and the amount of sealed fluid F in the deep groove 17 is stabilized. In other words, the sealed fluid F supplied between the sliding surfaces 11 and 21 from the fluid-side spiral groove 13 or the fluid-side reverse spiral groove 14 can be reliably recovered into the deep groove 17.

[0060] Furthermore, the ends 15A and 16A of the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c are in communication with the internal space S1. As a result, when the mechanical seal rotates relative to the internal space S1, atmospheric air A can be introduced into the leak-side spiral grooves 15a to 15c, and when it rotates relative to the internal space S1, atmospheric air A can be introduced into the leak-side reverse spiral grooves 16a to 16c, thereby stably generating positive pressure in the leak-side spiral grooves 15a to 15c and the leak-side reverse spiral grooves 16a to 16c.

[0061] Furthermore, the ends 15B of the leak-side spiral grooves 15a to 15c and the ends 16B of the leak-side reverse spiral grooves 16a to 16c are positioned on the outer diameter side, i.e., on the outer space S2 side, than the ends 13B of the fluid-side spiral groove 13 and the ends 14B of the fluid-side reverse spiral groove 14. This ensures that the length of each spiral groove is sufficiently maintained.

[0062] Furthermore, since the deep groove 17 has a first portion 171 that extends along the fluid-side spiral groove 13 and the leak-side reverse spiral grooves 16a to 16c, and a second portion 172 that extends along the fluid-side reverse spiral groove 14 and the leak-side spiral grooves 15a to 15c, multiple spiral grooves can be efficiently arranged in the circumferential direction. [Examples]

[0063] Next, the sliding parts according to Example 2 will be described with reference to Figure 5. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0064] In this embodiment 2, an annular land 18 is provided on the inner diameter side edge of the sliding surface 111 of the stationary sealing ring 100. On the outer diameter side of the annular land 18, an annular deep groove 117 is formed concentrically with the stationary sealing ring 100 as a communication groove. This annular deep groove 117 and the third portion 173 of the deep groove 17 are separated by a land 112 that constitutes the leakage side region A20. The annular deep groove 117 is formed to a depth such that almost no dynamic pressure is generated by the relative rotation of the mechanical seal.

[0065] On the outer diameter side of the annular deep groove 117, leak-side spiral grooves 151a to 151c and leak-side reverse spiral grooves 161a to 161c are provided. Each end 151A of the leak-side spiral grooves 151a to 151c and each end 161A of the leak-side reverse spiral grooves 161a to 161c are in communication with the annular deep groove 117. The configuration other than that described above is the same as that of Embodiment 1.

[0066] According to this, when the mechanical seal rotates relative to the other side in the forward direction, the sealed fluid F collected in the leak-side reverse spiral grooves 161a to 161c can be guided through the annular deep groove 117 to the leak-side spiral grooves 151a to 151c. Also, when the mechanical seal rotates relative to the other side in the reverse direction, the sealed fluid F collected in the leak-side spiral grooves 151a to 151c can be guided through the annular deep groove 117 to the leak-side reverse spiral grooves 161a to 161c. Therefore, the sealed fluid F collected in the leak-side spiral grooves 151a to 151c and the leak-side reverse spiral grooves 161a to 161c is less likely to leak into the internal space S1.

[0067] Furthermore, the annular deep groove 117 can also recover the sealed fluid F from the lands 112 that constitute the leak-side region A20, i.e., the portions other than the leak-side spiral grooves 151a to 151c and the leak-side reverse spiral grooves 161a to 161c.

[0068] Furthermore, an annular land 18 is formed on the inner diameter side of the annular deep groove 117. In other words, since the annular deep groove 117 and the inner space S1 are separated by the annular land 18, the sealed fluid F collected in the annular deep groove 117 is less likely to leak into the inner space S1.

[0069] In this embodiment, a configuration in which the deep groove and the annular connecting groove are separated by a land is illustrated, but the deep groove and the annular connecting groove may be in communication with each other. [Examples]

[0070] Next, the sliding parts according to Embodiment 3 will be described with reference to Figure 6. Note that descriptions of components that are identical to those in Embodiment 2 and therefore redundant will be omitted.

[0071] In this embodiment 3, the fluid-side region A10 of the sliding surface 211 of the stationary sealing ring 200 is provided with two fluid-side spiral grooves 213a and 213b, and two fluid-side reverse spiral grooves 214a and 214b.

[0072] The fluid-side spiral groove 213a is longer than the fluid-side spiral groove 213b. Furthermore, the fluid-side spiral groove 213a is positioned in the opposite direction of rotation of the fluid-side spiral groove 213b to the rotating sealing ring 20.

[0073] The fluid-side reverse spiral groove 214a is longer than the fluid-side reverse spiral groove 214b and is the same length as the fluid-side spiral groove 213a. Furthermore, the fluid-side reverse spiral groove 214a is positioned in the forward rotation direction of the rotating sealing ring 20 of the fluid-side reverse spiral groove 214b.

[0074] Furthermore, the fluid-side spiral groove 213b and the fluid-side reverse spiral groove 214b are of the same length. Note that all other configurations are the same as those in Example 2. [Examples]

[0075] Next, the sliding parts according to Embodiment 4 will be described with reference to Figure 7. Note that descriptions of components that are identical to those in Embodiment 2 and therefore redundant will be omitted.

[0076] In this embodiment 4, the sliding surface 311 of the stationary sealing ring 300 is provided with a continuous deep groove 317 extending in the circumferential direction. This deep groove 317 has a first portion 317a, a second portion 317b, a third portion 317c, and a fourth portion 317d.

[0077] The first portion 317a is a portion that extends substantially parallel to the fluid-side spiral groove 13 and the leak-side reverse spiral grooves 161a to 161c. The outer diameter end of the first portion 317a does not communicate with the outer space S2. The second portion 317b is a portion that extends substantially parallel to the fluid-side reverse spiral groove 14 and the leak-side spiral grooves 151a to 151c. The outer diameter end of the second portion 317b does not communicate with the outer space S2.

[0078] The third portion 317c extends concentrically with the stationary sealing ring 300 and connects the inner diameter ends of the first portion 317a and the second portion 317b. The fourth portion 317d extends concentrically with the stationary sealing ring 300 and connects the outer diameter ends of the first portion 317a and the second portion 317b.

[0079] According to this, since an endless deep groove 317 is arranged between the leak-side region A20' and the outer space S2, the inflow of the sealed fluid F into the leak-side region A20' is reduced, and thus the leakage of the sealed fluid F into the inner space S1 can be minimized. [Examples]

[0080] Next, the sliding parts according to Example 5 will be described with reference to Figure 8. Note that descriptions of components that are identical to those in Example 2 and therefore redundant will be omitted.

[0081] The mechanical seal in this embodiment 5 is an outside type, where the sealed fluid F in the inner space S1 is sealed, and the outer space S2 is open to the atmosphere A. In other words, in this embodiment 5, the inner space S1 functions as the fluid-side space, and the outer space S2 functions as the leak-side space.

[0082] In this embodiment 5, the sliding surface 411 of the stationary sealing ring 400 has an annular land 18' on its outer diameter side edge. An annular deep groove 117' is formed on the inner diameter side of the annular land 18' as a communicating groove. On the inner diameter side of the annular deep groove 117', four deep grooves 417 are provided in the circumferential direction, with both ends communicating with the inner space S1. The deep grooves 417 do not communicate with the outer space S2.

[0083] The fluid-side region A100 is provided with fluid-side spiral grooves 413 and fluid-side reverse spiral grooves 414. The leak-side region A200 is provided with leak-side spiral grooves 451a to 451c and leak-side reverse spiral grooves 461a to 461c. The leak-side spiral grooves 451a to 451c and the leak-side reverse spiral grooves 461a to 461c communicate with the annular deep groove 117' and extend toward the inner diameter.

[0084] 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.

[0085] For example, in the above embodiments 1 to 5, mechanical seals were used as examples of sliding parts, but other mechanical seals such as those used in general industrial machinery, automobiles, or water pumps may also be used. Furthermore, the invention is not limited to mechanical seals, but may also use sliding parts other than mechanical seals, such as sliding bearings.

[0086] Furthermore, while embodiments 1 to 5 illustrate configurations in which the fluid side groove and the fluid side reverse groove are directly connected to the fluid side space, as shown in the stationary sealing ring 500 in Figure 9, the fluid side groove 513 may extend concentrically in one direction circumferentially from the first portion 171 of the deep groove 17 with respect to the stationary sealing ring 500, and the fluid side reverse groove 514 may extend concentrically in another direction circumferentially from the second portion 172 of the deep groove 17 with respect to the stationary sealing ring 500. In other words, the fluid side groove 513 and the fluid side reverse groove 514 may be connected to the outer space S2, i.e., the fluid side space, via the deep groove 17. Also, the fluid side groove 513 and the fluid side reverse groove 514 do not have a radial component; that is, they do not have to be spiral grooves.

[0087] Furthermore, while the above-described embodiments 1 to 5 illustrate a configuration in which the fluid side groove and the fluid side reverse groove have symmetrical shapes, and the leak side groove and the leak side reverse groove have symmetrical shapes, and positive pressure and relative negative pressure are generated in the same way in both the forward and reverse directions of relative rotation, the invention is not limited to this configuration. Each groove may have an asymmetrical shape, so that positive pressure and relative negative pressure are generated differently in the forward and reverse directions of relative rotation.

[0088] Furthermore, while embodiments 1 to 5 above illustrate a configuration in which the connecting grooves connecting the respective leak-side ends of the leak-side groove and the reverse leak-side groove are deep grooves, they may also be shallow grooves having a depth sufficient to generate dynamic pressure due to the relative rotation of the mechanical seal.

[0089] Furthermore, while embodiments 2 to 5 above illustrate an annular configuration for the connecting groove, the invention is not limited to this, and the connecting groove may extend in an arc shape to connect the leak-side ends of the leak-side groove and the reverse leak-side groove. The connecting groove is not limited to an arc shape; it may also extend in a sinusoidal or linear shape.

[0090] Furthermore, the number of each groove and deep groove may be freely changed.

[0091] Furthermore, while embodiments 1 to 5 above illustrate configurations in which the degree of inclination in the circumferential direction of the fluid side groove and the leak side reverse groove, as viewed from the axial direction, is approximately the same, the degree of inclination in the circumferential direction may differ.

[0092] Furthermore, while embodiments 1 to 5 above illustrate a configuration in which each groove is provided on a stationary sealing ring, the grooves may also be provided on a rotating sealing ring.

[0093] Furthermore, while embodiments 1 to 5 above illustrate a configuration in which each groove has a certain depth in the extension direction, steps or inclined surfaces may be formed on the bottom surface of the grooves.

[0094] Furthermore, while embodiments 1 to 5 described above illustrate configurations in which the fluid side groove and fluid side reverse groove are shallower and have a smaller capacity than the leak side groove and leak side reverse groove, the depth and capacity of the fluid side groove and fluid side reverse groove may be formed to be approximately the same as the depth and capacity of the leak side groove and leak side reverse groove.

[0095] Furthermore, while we have described the sealed fluid side as the high-pressure side and the leak side as the low-pressure side, the sealed fluid side may be the low-pressure side and the leak side the high-pressure side, or the sealed fluid side and the leak side may be at approximately the same pressure.

[0096] Furthermore, although the sealed fluid F was described as a high-pressure liquid in Examples 1 to 5, it is not limited to this; it may also be a gas or a low-pressure liquid, or a mist-like mixture of liquid and gas.

[0097] Furthermore, although the leaking fluid in Examples 1 to 5 was described as atmospheric air A, which is a low-pressure gas, it is not limited to this; it may also be a liquid or a high-pressure gas, or a mist-like mixture of liquid and gas. [Explanation of Symbols]

[0098] 10 Stationary sealing ring 11 Sliding surface 12 Land 13. Fluid-side spiral groove (fluid-side groove) 13A end 13B End (Terminal) 14. Fluid-side reverse spiral groove (fluid-side reverse groove) 14A End 14B End (Terminal) 15A end 15B End (Terminal end, Leak-side end) 15a~15c Leak-side spiral groove (leak-side groove) 16A end 16B End (Terminal) 16a~16c Leak-side reverse spiral groove (leak-side reverse groove) 17 deep groove 18 Ring Land 20 Rotating Sealing Rings 21 Sliding surface 117 Annular deep groove A atmosphere A1 Fluid side area A2 Leakage side area F Sealed fluid S1 Internal space (leakage side space) S2 Outside space (fluid side space)

Claims

1. A sliding component that is positioned opposite to a part that rotates relative to it when a rotating machine is driven, and has a pair of sliding surfaces that separate the fluid-side space from the leakage-side space, On one of the sliding surfaces, A fluid side groove that communicates with the aforementioned fluid side space and extends in the positive direction of relative rotation, A fluid-side reverse groove that communicates with the fluid-side space and extends in the opposite direction of relative rotation, A leak groove having at least one end positioned on the leak-side space side of the fluid-side groove and the fluid-side reverse groove, and extending from that end toward the fluid-side space in the relative rotational positive direction, At least one end of the leak-side reverse groove is positioned on the leak-side space side of the fluid-side groove and the fluid-side reverse groove, and the leak-side reverse groove extends from that end toward the fluid-side space in the opposite direction of relative rotation, A deep groove is provided that separates the fluid-side region where the fluid-side groove and the fluid-side reverse groove are provided from the leak-side region where the leak-side groove and the leak-side reverse groove are provided. The end portions of the leakage side groove and the leakage side reverse groove are positioned on the fluid side space side than the end portions of the fluid side groove and the fluid side reverse groove. The deep groove extends to surround the fluid side groove and the fluid side reverse groove, Within the fluid-side region, the fluid-side reverse groove is a sliding component provided downstream of the fluid-side groove in the relative positive rotation direction.

2. The sliding component according to claim 1, wherein the deep groove is in communication with the fluid-side space.

3. The sliding component according to claim 1 or 2, wherein the respective leak-side ends of the leak-side groove and the leak-side reverse groove communicate with the leak-side space.

4. The sliding component according to claim 1 or 2, wherein one of the sliding surfaces is provided with a communication groove that connects the respective leak-side ends of the leak-side groove and the leak-side reverse groove.

5. The sliding part according to claim 4, wherein the communication groove is annular.

6. The fluid side groove, the leak side reverse groove, the fluid side reverse groove, and the leak side groove are arranged at an inclination. The sliding part according to claim 1, wherein the deep groove has a first inclined portion extending along the fluid side groove and the leak side reverse groove, and a second inclined portion extending along the fluid side reverse groove and the leak side groove.

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