Sliding parts

Abstract

Provided is a sliding component that has high sealing quality during forward rotation, and has small torque during reverse rotation.　A pair of sliding rings 10, 20 mutually rotate relative to each other, and an annular sliding component 10 defines a gap between a sealed fluid space S1 and a leakage space S2. The sliding component 10 has a dynamic pressure generation groove 13 that generates dynamic pressure. The dynamic pressure generation groove 13 comprises: an inclined groove 14 that is inclined and extends in a forward rotation direction from the leakage space S2 toward the sealed fluid space S1, and has a first dynamic pressure generation end portion 13C; and a reverse groove 15 that extends from the reverse rotation direction side of the inclined groove 14 in a reverse rotation direction, and has a second dynamic pressure generation end portion 13D.

Description

Technical Field

[0001] The present invention relates to sliding parts that rotate relative to each other, and is used, for example, for sliding parts used in a shaft sealing device that seals a rotating shaft of a rotating machine in the field of automobiles, general industrial machines, or other sealing fields, or for sliding parts used in bearings of machines in the field of automobiles, general industrial machines, or other bearing fields.

Background Art

[0002] For example, a mechanical seal as a shaft sealing device for preventing leakage of a sealed fluid includes a pair of annular sliding parts that rotate relative to each other and whose sliding surfaces slide against each other. In such a mechanical seal, in recent years, reduction of energy lost due to sliding is desired for environmental protection and other reasons.

[0003] For example, the mechanical seal shown in Patent Document 1 is provided with a hydrodynamic groove and a fluid introduction groove. The hydrodynamic groove has an inclined groove that communicates with the inner space on the leakage side and extends toward the outer diameter side, and a reverse inclined groove that is continuously formed on the outer diameter side of the inclined groove and extends in the opposite direction to the inclined groove, and forms a substantially L shape in the axial view. The fluid introduction groove is composed of a fluid guiding groove portion that communicates with the outer space and a release step that extends circumferentially concentrically with the stationary seal ring from the inner diameter side of the fluid guiding groove portion in the forward rotation direction of the rotating seal ring. The sealed fluid exists in the outer space, and the atmosphere exists in the inner space.

[0004] When the rotating seal ring rotates forward at a low speed, the sealed fluid flowing out from the fluid introduction groove between the sliding surfaces lubricates the sliding surfaces, suppressing wear between the sliding surfaces. At the same time, the positive pressure generated at the pressure generating portion provided at the corner between the side wall portion of the inclined groove and the side wall portion of the reverse inclined groove pushes the sealed fluid flowing into the sliding surfaces back to the outer space side, so that leakage of the sealed fluid from between the sliding surfaces into the inner space is suppressed. Also, when the rotating seal ring rotates forward at a high speed, the positive pressure generating ability of the entire inclined groove becomes greater than the positive pressure generating ability of the entire release step, and it becomes gas lubricated.

[0005] On the other hand, when the rotating sealing ring rotates in the reverse direction, the positive pressure generated by the pressure generating section provided at the outer diameter end of the reverse-inclined groove slightly separates the sliding surfaces, allowing the sealed fluid to flow in and improving lubrication. At the same time, the sealed fluid that has flowed between the sliding surfaces is pushed back to the outer space, thus preventing the sealed fluid from leaking into the inner space from between the sliding surfaces. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2021 / 246371 (page 13, Figure 3) [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in sliding parts such as those described in Patent Document 1, a reverse inclined groove is continuously extended on the outer diameter side of the inclined groove. When the rotating sealing ring rotates in the forward direction, the sealed fluid drawn into the reverse inclined groove tends to flow along the side wall of the reverse inclined groove. As a result, there was a risk that the sealed fluid drawn into the reverse inclined groove could not be sufficiently discharged from the inclined groove or the reverse inclined groove to the outer diameter side.

[0008] This invention was made in view of these problems, and aims to provide a sliding part that has high sealing performance during forward rotation and low torque during reverse rotation. [Means for solving the problem]

[0009] To solve the aforementioned problems, the sliding component of the present invention is A sliding component comprising a pair of sliding rings that rotate relative to each other, thereby separating a sealed fluid space from a leak space, The sliding part has a dynamic pressure generating groove that generates dynamic pressure. The dynamic pressure generating groove is An inclined groove extending in a forward rotational direction from the leakage space toward the sealed fluid space and having a first dynamic pressure generating end, The system includes a reverse groove extending in the reverse direction from the reverse rotation direction side of the inclined groove and having a second dynamic pressure generating end. According to this, during relative forward rotation of the sliding parts, the sealed fluid drawn in at or near the second dynamic pressure generating end moves toward the inclined groove and is easily discharged from the first dynamic pressure generating end between the sliding surfaces. Furthermore, during relative reverse rotation of the sliding parts, positive pressure is generated at or near the second dynamic pressure generating end. As a result, the sliding parts have high sealing performance during forward rotation and low torque during reverse rotation.

[0010] The second dynamic pressure generating end extends from the closed end of the inclined groove, The first dynamic pressure generating end is located on the same circumference as the second dynamic pressure generating end. According to this, when the sliding parts rotate in the forward direction relative to each other, the fluid that flows out between the sliding surfaces from the adjacent upstream inclined groove, mainly from its first dynamic pressure generating end, is easily recovered at or near the second dynamic pressure generating end of its own reverse groove. Similarly, when the sliding parts rotate in the reverse direction relative to each other, the fluid that flows out between the sliding surfaces from the adjacent upstream reverse groove, mainly from its second dynamic pressure generating end, is easily recovered at or near the first dynamic pressure generating end of its own inclined groove. Furthermore, since the second dynamic pressure generating end is located on the sealed fluid space side of the inclined groove, it is easy to generate positive pressure in the reverse groove when the sliding parts rotate in the reverse direction relative to each other.

[0011] The first dynamic pressure generating end may be positioned closer to the sealed fluid space than the second dynamic pressure generating end. According to this, when the sliding parts rotate in the relative forward direction, the sealed fluid drawn in at or near the second dynamic pressure generating end is moved in the circumferential direction and in the direction of the sealed fluid, and is easily discharged from the first dynamic pressure generating end into the space between the sliding surfaces.

[0012] The first dynamic pressure generating end may be located on the leakage space side of the second dynamic pressure generating end. According to this, when the sliding parts rotate in the opposite direction relative to each other, the sealed fluid drawn in at or near the first dynamic pressure generating end is moved in the circumferential direction and in the direction of the sealed fluid, and is easily discharged from the second dynamic pressure generating end between the sliding surfaces.

[0013] The surfaces on the side of the fluid space to be sealed of the first dynamic pressure generating end portion and the second dynamic pressure generating end portion may be continuous on the same surface. According to this, fluid can smoothly move between the first dynamic pressure generating end portion and the second dynamic pressure generating end portion.

[0014] The surfaces on the side of the fluid space to be sealed of the first dynamic pressure generating end portion and the second dynamic pressure generating end portion may be continuous by the same arc-shaped surface. According to this, fluid can move more smoothly between the first dynamic pressure generating end portion and the second dynamic pressure generating end portion.

[0015] The first dynamic pressure generating end portion may form an acute angle in the axial direction view. According to this, the positive pressure generating effect at the first dynamic pressure generating end portion is high.

[0016] The first dynamic pressure generating end portion may taper in the forward rotation direction, and its tip may form a curved surface. According to this, the positive pressure generating effect at the first dynamic pressure generating end portion is high.

[0017] The second dynamic pressure generating end portion may form an acute angle in the axial direction view. According to this, the positive pressure generating effect at the second dynamic pressure generating end portion is high.

[0018] The second dynamic pressure generating end portion may taper in the reverse rotation direction, and its tip may form a curved surface. According to this, the positive pressure generating effect at the second dynamic pressure generating end portion is high.

[0019] The fluid space to be sealed may be provided with fluid inlet / outlet grooves communicating therewith. According to this, the lubricity between the sliding surfaces at low speeds can be enhanced.

[0020] ]> The fluid inlet / outlet grooves may be provided with dynamic pressure generating portions. According to this, due to the dynamic pressure generating portion, dynamic pressure can be generated to slightly separate the sliding surfaces from each other and introduce the fluid to be sealed between the sliding surfaces, so that the lubricity between the sliding surfaces can be enhanced.

[0021] Furthermore, in the sliding surface of the sliding part according to the present invention, the inclined groove only needs to have a radial component and a circumferential component in the extending direction of the inclined groove. Also, the reverse groove only needs to have a component in a direction opposite to at least the circumferential direction of the inclined groove in the extending direction of the reverse groove.

[0022] Furthermore, the fluid to be sealed may be a gas or a liquid, or may be in a mist state in which a liquid and a gas are mixed.

Brief Description of the Drawings

[0023] [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 sliding surface of the stationary seal ring in Example 1 as seen from the axial direction. [Figure 4] It is an explanatory view of the movement of the fluid in the inclined groove and the reverse inclined groove during forward rotation of the sliding surface of the stationary seal ring in Example 1 as seen from the axial direction. [Figure 5] It is an explanatory view of the movement of the fluid in the inclined groove and the reverse inclined groove during reverse rotation of the sliding surface of the stationary seal ring in Example 1 as seen from the axial direction. [Figure 6] It is an enlarged 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 an enlarged view of the sliding surface of the stationary seal ring in Example 3 of the present invention as seen from the axial direction. [Figure 8] It is a schematic view showing Modification 3-1 in Example 3 of the present invention. [Figure 9] It is a schematic view showing Modification 3-2 in Example 3 of the present invention. <​​​​​​ [Figure 12] This is a schematic diagram showing a modified example 3-5 of the present invention. [Figure 13] This is an enlarged view of the sliding surface of the stationary sealing ring in Embodiment 4 of the present invention, as seen from the axial direction. [Figure 14] This is an enlarged view of the sliding surface of the stationary sealing ring in Embodiment 5 of the present invention, as seen from the axial direction. [Figure 15] This is a schematic diagram of the sliding surface of the stationary sealing ring in Embodiment 6 of the present invention, viewed from the axial direction. [Figure 16] This is a schematic diagram showing a modified example 6-1 of Embodiment 6 of the present invention. [Figure 17] This is a schematic diagram showing a modified example 6-2 of Embodiment 6 of the present invention. [Figure 18] This is a schematic diagram showing a modified example 6-3 of Embodiment 6 of the present invention. [Figure 19] This is a schematic diagram of the sliding surface of the stationary sealing ring in Embodiment 7 of the present invention, viewed from the axial direction. [Figure 20] This is a schematic diagram of the sliding surface of the stationary sealing ring in Embodiment 8 of the present invention, viewed from the axial direction. [Figure 21] This is a schematic diagram of the sliding surface of the stationary sealing ring in Embodiment 9 of the present invention, viewed from the axial direction. [Figure 22] This is a schematic diagram of the sliding surface of the stationary sealing ring in Embodiment 10 of the present invention, viewed from the axial direction. [Figure 23] This is an enlarged view of the sliding surface of the stationary sealing ring in Embodiment 11 of the present invention, as seen from the axial direction. [Figure 24] This is an explanatory diagram showing an example of a sliding part that does not fall under the sliding parts of the present invention. [Modes for carrying out the invention]

[0024] Embodiments for implementing the sliding component according to the present invention will be described below based on examples. [Examples]

[0025] The sliding component according to Example 1 will be described with reference to Figures 1 to 5. In this example, the sliding component is described as a mechanical seal. Furthermore, the sealed fluid is present in the inner space of the mechanical seal, and the atmosphere is present in the outer space. The inner diameter side of the sliding component constituting the mechanical seal will be described as the sealed fluid side (high pressure side), and the outer diameter side as the leakage side (low pressure side). Also, for the sake of explanation, dots may be added to grooves, etc., formed on the sliding surface in the drawings.

[0026] The automotive mechanical seal shown in Figure 1 is an outside-type seal that seals the fluid F to be sealed, which is attempting to leak from the inner diameter side to the outer diameter side of the sliding surface, and the outer space S2 is open to the atmosphere A. In this embodiment, the example shown is one in which the fluid to be sealed F is a high-pressure liquid and the atmosphere A is a gas at a lower pressure than the fluid to be sealed F.

[0027] The mechanical seal mainly consists of a rotating sealing ring 20 as another annular sliding part and an annular stationary sealing ring 10 as a sliding part. The rotating sealing ring 20 is mounted on the rotating shaft 1 via a sleeve 2 so as to be rotatable with the rotating shaft 1. The stationary sealing ring 10 is mounted on a seal cover 5 fixed to the housing 4 of the equipment to be mounted, in a non-rotatable and axially movable state. The stationary sealing ring 10 is biased axially 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 this flat surface does not have any grooves or other recesses.

[0028] 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 this. Any sliding material used for mechanical seals is applicable. SiC can be sintered using boron, aluminum, carbon, etc., as sintering aids, or from materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, SiC-TiN, etc. Carbon can be a mixture of carbonaceous and graphite, as well as resin-molded carbon and sintered carbon. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), and composite materials are also applicable.

[0029] As shown in Figures 2 and 3, the rotating sealing ring 20, which is the mating sealing ring, slides relative to the stationary sealing ring 10 in a counterclockwise direction as indicated by the solid arrows, or in a clockwise direction as indicated by the dotted arrows. Hereafter, the rotation direction indicated by the solid arrows will be described as the forward rotation direction, and the rotation direction indicated by the dotted arrows will be described as the reverse rotation direction.

[0030] On the sliding surface 11 of the stationary sealing ring 10, a plurality of dynamic pressure generating grooves 13 are evenly arranged in the circumferential direction on the outer diameter side, and a plurality of fluid introduction grooves 16, which serve as fluid outlet and inlet grooves, are evenly arranged in the circumferential direction on the inner diameter side. In this embodiment, the fluid introduction grooves 16 have the function of introducing fluid, but they may also be used to discharge fluid.

[0031] Furthermore, the portion of the sliding surface 11 other than the dynamic pressure generating grooves 13 and fluid introduction grooves 16 forms a flat land 12. Specifically, the land 12 has a land portion 12a between circumferentially adjacent dynamic pressure generating grooves 13, a land portion 12b between circumferentially adjacent fluid introduction grooves 16, and a land portion 12c between radially spaced dynamic pressure generating grooves 13 and fluid introduction grooves 16. The upper surfaces (i.e., axial end faces) of each of these land portions are arranged in the same plane, forming the flat surface of the land 12.

[0032] As shown in Figure 3, the dynamic pressure generating groove 13 is composed of an inclined groove 14 that extends from the outer diameter side to the inner diameter side and generates dynamic pressure, and a reverse groove 15 that is continuously formed on the inner diameter side of the inclined groove 14 and extends in the opposite direction in the circumferential direction to the inclined groove 14 and generates dynamic pressure, forming a roughly L-shape in the axial direction, that is, a so-called hook shape.

[0033] The dynamic pressure generating groove 13 has an outer diameter end 13A, that is, the outer diameter end of the inclined groove 14, which communicates with the outer space S2, and extends in an arc shape from the outer diameter end 13A toward the inner diameter side, inclined in the direction of forward rotation of the rotating sealing ring 20.

[0034] The portion of the inner diameter end 13B of the dynamic pressure generating groove 13 that is on the forward rotation side, i.e., the inner diameter end of the inclined groove 14, is a closed pressure generating end 13C, which serves as a first dynamic pressure generating end. The portion of the inner diameter end 13B of the dynamic pressure generating groove 13 that is on the reverse rotation side, i.e., the reverse rotation side of the reverse groove 15, is a closed reverse pressure generating end 13D, which serves as a second dynamic pressure generating end. The pressure generating end 13C generates positive pressure during forward rotation, and the reverse pressure generating end 13D generates positive pressure during reverse rotation.

[0035] Furthermore, the dynamic pressure generating groove 13 is not limited to extending in an arc shape inclined in the forward rotation direction of the rotating sealing ring 20; for example, it may extend in a straight line inclined in the forward rotation direction of the rotating sealing ring 20.

[0036] As shown in Figure 3, the inclined groove 14 consists of a bottom surface 14a that is flat in the direction of extension and parallel to the flat surface of the land 12, side wall portions 14c and 14d that extend perpendicularly from both side edges of the bottom surface 14a toward the flat surface of the land 12, and a wall portion 14b that extends perpendicularly from the inner diameter end edge of the bottom surface 14a toward the flat surface of the land 12. The bottom surface 14a has a substantially rectangular shape with both side wall portions 14c and 14d being substantially parallel.

[0037] The pressure generating end 13C is the portion of the dynamic pressure generating groove 13 enclosed by the bottom surface 14a, the side wall portion 14d, and the wall portion 14b. This pressure generating end 13C tapers towards the forward rotation direction of the rotating sealing ring 20 and forms an acute angle in an axial view.

[0038] The reverse groove 15 consists of a bottom surface 15a that is flat in the direction of extension and parallel to the flat surface of the land 12, a side wall portion 15c that extends perpendicularly from the outer diameter side edge of the bottom surface 15a toward the flat surface of the land 12, and a wall portion 15b that extends perpendicularly from the inner diameter side edge of the bottom surface 15a toward the flat surface of the land 12. The side wall portion 15c extends in a straight line when viewed from the axial direction. The bottom surface 15a is approximately triangular in shape.

[0039] The reverse pressure generating end 13D is the portion of the dynamic pressure generating groove 13 enclosed by the bottom surface 15a, the side wall portion 15c, and the wall portion 15b. This reverse pressure generating end 13D tapers towards the reverse rotation direction of the rotating sealing ring 20, forming an acute angle in axial view.

[0040] In this embodiment, the side wall portion 15c is shown as extending in a straight line when viewed from the axial direction, but the embodiment is not limited to this, and the side wall portion may extend in other shapes such as an arc shape or a wave shape.

[0041] The wall portion 14b of the inclined groove 14 and the wall portion 15b of the reverse groove 15 are continuous in the circumferential direction without any bends. In other words, the wall portion 14b of the inclined groove 14 and the wall portion 15b of the reverse groove 15 are composed of a single arc-shaped wall portion 13a, which is an arc-shaped surface extending circumferentially concentrically with the stationary sealing ring 10.

[0042] In other words, the pressure generating end 13C and the reverse pressure generating end 13D are arranged on the same circumference of the sliding surface 11.

[0043] Furthermore, the total length of the reverse groove 15 is shorter than the total length of the inclined groove 14.

[0044] Furthermore, the depth of the reverse groove 15 is the same as the depth of the inclined groove 14. That is, the bottom surface 15a of the reverse groove 15 is arranged on the same plane as the bottom surface 14a of the continuous inclined groove 14 and forms a flat surface. Note that the bottom surface 14a of the inclined groove 14 and the bottom surface 15a of the reverse groove 15 are not limited to being flat surfaces, but may have inclines or irregularities. As shown in Figure 3, the fluid introduction groove 16 consists of a fluid guide groove section 17 that communicates with the internal space S1, and Rayleigh steps 18, 18' as dynamic pressure generating sections that extend circumferentially from the outer diameter side of the fluid guide groove section 17 in the forward and reverse rotation directions of the rotating sealing ring 20 concentrically with the stationary sealing ring 10.

[0045] Furthermore, the fluid guide groove 17 is formed to a depth greater than that of the dynamic pressure generating groove 13. Also, the Rayleigh steps 18 and 18' are formed to a depth shallower than that of the fluid guide groove 17 and to approximately the same depth as that of the dynamic pressure generating groove 13. However, the fluid guide groove 17 may have the same depth as the dynamic pressure generating groove 13. In addition, the circumferential length of the Rayleigh steps 18 and 18' is formed to be greater than the circumferential length of the fluid guide groove 17 or the circumferential length of one of the dynamic pressure generating grooves 13.

[0046] Next, the operation of the stationary sealing ring 10 and the rotating sealing ring 20 during relative rotation will be explained using Figures 4 and 5. In this embodiment, the operation will be explained in the order of when the rotating sealing ring 20 is stopped, when it is rotating in the forward direction, and when it is rotating in the reverse direction.

[0047] First, when the rotating sealing ring 20 is stopped and not rotating, the fluid to be sealed F flows into the fluid introduction groove 16. 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 there is almost no leakage of the fluid to be sealed F between the sliding surfaces 11 and 21 into the outer space S2.

[0048] As shown in Figure 4, at low speeds immediately after the rotating sealing ring 20 begins to rotate relative to the stationary sealing ring 10 in the forward rotation direction, the sealed fluid F within the Rayleigh step 18 moves in the forward rotation direction of the rotating sealing ring 20 due to shear with the sliding surface 21.

[0049] In other words, within the fluid introduction groove 16, the sealed fluid F moves from the fluid guide groove 17 toward the downstream end 18A in the relative rotation direction of the Rayleigh step 18, and a force acts in the fluid guide groove 17 to pull the sealed fluid F in as shown by arrow H1. Note that the flow of the sealed fluid F and the atmosphere A in Figure 4 is shown schematically without specifying the relative rotation speed of the rotating sealing ring 20.

[0050] As the sealed fluid F moves toward the end 18A of the Rayleigh step 18, the pressure increases at and near the end 18A of the Rayleigh step 18. In other words, positive pressure is generated at and near the end 18A of the Rayleigh step 18.

[0051] Because the Rayleigh step 18 is shallow, even with a small amount of movement of the sealed fluid F due to the low rotational speed of the rotating sealing ring 20, positive pressure is generated at the end 18A of the Rayleigh step 18 and its vicinity.

[0052] Furthermore, the positive pressure generated at and near the end 18A of the Rayleigh step 18 causes the sliding surfaces 11 and 21 to separate slightly. As a result, the sealed fluid F flows into the space between the sliding surfaces 11 and 21 from the end 18A of the Rayleigh step 18 (see arrow H2) and the inner space S1. The presence of the sealed fluid F between the sliding surfaces 11 and 21 improves lubrication even at low rotational speeds and suppresses wear between the sliding surfaces 11 and 21. Moreover, because the floating distance between the sliding surfaces 11 and 21 is small, little of the sealed fluid F leaks out into the outer space S2. In addition, because the fluid guide groove 17 is provided, a large amount of the sealed fluid F can be held, preventing poor lubrication at low rotational speeds.

[0053] Furthermore, at low speeds immediately after the rotating sealing ring 20 begins to rotate relative to the stationary sealing ring 10 in the forward rotation direction, the sealed fluid F within the Rayleigh step 18' moves in the forward rotation direction of the rotating sealing ring 20 due to shear with the sliding surface 21, thereby generating a relative negative pressure at and near the end 18A' of the Rayleigh step 18'. As a result, the sealed fluid F that flows out from the end 18A of the Rayleigh step 18 between the sliding surfaces 11 and 21 is recovered inward from the end 18A', as shown by arrow H3.

[0054] On the other hand, in the dynamic pressure generating groove 13, when the relative rotation speed between the rotating sealing ring 20 and the stationary sealing ring 10 is low, the atmosphere A does not become sufficiently dense within the dynamic pressure generating groove 13, and high positive pressure is not generated. Therefore, the force due to the positive pressure generated by the dynamic pressure generating groove 13 is relatively small compared to the force due to the positive pressure generated at the end 18A of the Rayleigh step 18 and its vicinity. Thus, when the rotating sealing ring 20 rotates at a low speed, the force due to the positive pressure generated at the end 18A of the Rayleigh step 18 and its vicinity is the main force that separates the sliding surfaces 11 and 21 from each other.

[0055] As the relative rotational speed of the rotating sealing ring 20 increases, as shown in Figure 4, the air A in the dynamic pressure generating groove 13 moves in the forward rotational direction of the rotating sealing ring 20 due to shear with the sliding surface 21, and air A in the outer space S2 is drawn into the dynamic pressure generating groove 13. That is, within the dynamic pressure generating groove 13, a large amount of air A moves from the outer diameter end 13A toward the inner diameter end 13B as shown by arrow L1.

[0056] Specifically, as shown in the enlarged section of Figure 4, at the inner diameter end 13B of the dynamic pressure generating groove 13, two flows occur: one is a flow of air A flowing from the outer diameter side to the inner diameter side of the inclined groove 14, as indicated by arrow L1, and the other is a flow of air A and the sealed fluid F mixed together flowing circumferentially from the reverse pressure generating end 13D to the pressure generating end 13C, as indicated by arrow L3.

[0057] Specifically, the reverse pressure generating end 13D and its vicinity are under relative negative pressure compared to the surrounding area, so the sealed fluid F at the reverse pressure generating end 13D and its vicinity is drawn into the dynamic pressure generating groove 13. The sealed fluid F drawn into the dynamic pressure generating groove 13 moves toward the pressure generating end 13C along with the flow of air A, as shown by arrow L3.

[0058] At this time, the sealed fluid F that has been drawn into the dynamic pressure generating groove 13 moves smoothly along the arc-shaped wall portion 13a from the back pressure generating end 13D to the pressure generating end 13C, as shown by arrow L3.

[0059] As a result, the flow of air A indicated by arrow L1 and the flow of air A mixed with the sealed fluid F indicated by arrow L3 are both guided to the vicinity of the pressure generating end 13C, where the pressure is increased and positive pressure is generated at and near the pressure generating end 13C.

[0060] In this way, the force due to the positive pressure generated at the end 18A of the Rayleigh step 18 and its vicinity is added to the force due to the positive pressure generated at the pressure generating end 13C and its vicinity, causing the sliding surfaces 11 and 21 to separate further compared to when the speed is low. As a result, air A, mainly from the dynamic pressure generating groove 13 indicated by arrow L2, flows into the space between the sliding surfaces 11 and 21.

[0061] At this time, the air A containing the sealed fluid F, indicated by arrow L3, is pushed out from the pressure generating end 13C and its vicinity toward the inner diameter side, i.e., toward the sealed fluid F side, by the air A indicated by arrow L1, which has high energy such as flow velocity.

[0062] Furthermore, the sealed fluid F drawn into the dynamic pressure generating groove 13 tends to clump together at and near the pressure generating end 13C, and is easily discharged between the sliding surfaces 11 and 21 by the air A (see arrow L1) flowing through the dynamic pressure generating groove 13.

[0063] The air A inside the dynamic pressure generating groove 13, indicated by arrow L1, acts to push the sealed fluid F near the pressure generating end 13C of the dynamic pressure generating groove 13 back towards the inner space S1, so that little of the sealed fluid F leaks out into the dynamic pressure generating groove 13 or into the outer space S2.

[0064] Furthermore, a portion of the sealed fluid F discharged between the sliding surfaces 11 and 21 from the pressure generating end 13C indicated by arrow L2 is sucked into the reverse pressure generating end 13D of another dynamic pressure generating groove 13 adjacent in the forward rotation direction, so that little of the sealed fluid F leaks out into the outer space S2.

[0065] In this embodiment, the sliding components are designed so that, during high-speed forward rotation, the positive pressure generation capacity of the entire dynamic pressure generation groove 13 is sufficiently greater than the positive pressure generation capacity of the entire fluid introduction groove 16. As a result, ultimately, only air A is present between the sliding surfaces 11 and 21, i.e., gaseous lubrication is achieved.

[0066] Thus, when the rotating sealing ring 20 starts to rotate relative to the stationary sealing ring 10 in the forward rotation direction, the sealed fluid F flowing out from the fluid introduction groove 16 between the sliding surfaces 11 and 21 lubricates the sliding surfaces 11 and 21. During high-speed rotation, the positive pressure generated by the atmosphere A in the dynamic pressure generating groove 13 causes the sliding surfaces 11 and 21 to separate, introducing the sealed fluid F and atmosphere A between the sliding surfaces 11 and 21, thereby enhancing lubrication and suppressing wear between the sliding surfaces 11 and 21 from the start of relative rotation through high-speed rotation.

[0067] Next, the case of the rotating sealing ring 20 rotating in the reverse direction will be explained using Figure 5. As shown in Figure 5, when the rotating sealing ring 20 rotates relative to the stationary sealing ring 10 in the opposite direction, the sealed fluid F in the Rayleigh step 18 moves in the reverse direction of the rotating sealing ring 20 due to shear with the sliding surface 21. As a result, it enters the fluid guide groove 17 on the downstream side in the relative rotation direction, and a force acts in the fluid guide groove 17 to push out a portion of the sealed fluid F as shown by arrow H1'. Note that the flow of the sealed fluid F and the atmosphere A in Figure 5 are shown schematically without specifying the relative rotation speed of the rotating sealing ring 20.

[0068] Meanwhile, the sealed fluid F within the Rayleigh step 18' moves in the reverse rotation direction of the rotating sealing ring 20 due to shear with the sliding surface 21, generating positive pressure at its end 18A' and its vicinity. As a result, the sealed fluid F flows into the space between the sliding surfaces 11 and 21 from the end 18A' (see arrow H3') of the Rayleigh step 18' and from the inner space S1 side.

[0069] At this time, the sealed fluid F present in the land portion 12b (see Figure 3) between adjacent fluid introduction grooves 16 and the land portion 12c (see Figure 3) between the radially separated dynamic pressure generating groove 13 and the fluid introduction groove 16 is drawn into the fluid introduction groove 16 by the negative pressure generated at and near the end 18A of the Rayleigh step 18, as shown by arrow H2', and this tendency is particularly pronounced near the end 18A.

[0070] Thus, when the rotating sealing ring 20 rotates in the opposite direction relative to the stationary sealing ring 10, a large amount of the sealed fluid F drawn into the fluid introduction groove 16 is held in the fluid guide groove portion 17 and supplied from the end portion 18A' of the Rayleigh step 18' to the sliding surfaces 11 and 12, thereby preventing poor lubrication.

[0071] On the other hand, in the dynamic pressure generating groove 13, as shown in Figure 5, the sealed fluid F that enters the dynamic pressure generating groove 13 moves in the reverse rotation direction of the rotating sealing ring 20 due to shear with the sliding surface 21. That is, within the dynamic pressure generating groove 13, as shown in the enlarged section of Figure 5, the sealed fluid F flows circumferentially from the pressure generating end 13C to the reverse pressure generating end 13D, as indicated by arrow H6'.

[0072] At this time, the sealed fluid F that has been drawn into the dynamic pressure generating groove 13 indicated by arrow H6' moves smoothly along the arc-shaped wall portion 13a from the pressure generating end 13C to the reverse pressure generating end 13D.

[0073] As the sealed fluid F moves toward the reverse pressure generating end 13D, its pressure increases at and near the reverse pressure generating end 13D. In other words, positive pressure is generated at and near the reverse pressure generating end 13D.

[0074] Furthermore, the positive pressure generated at and near the reverse pressure generating end 13D causes the sliding surfaces 11 and 21 to separate slightly. As a result, the sealed fluid F, mainly from the dynamic pressure generating groove 13 indicated by arrow H4', flows into the space between the sliding surfaces 11 and 21.

[0075] The sealed fluid F flowing out from the reverse pressure generating end 13D indicated by arrow H4' acts to push the sealed fluid F near the reverse pressure generating end 13D of the dynamic pressure generating groove 13 back towards the inner space S1, so that little of the sealed fluid F leaks out into the dynamic pressure generating groove 13 or into the outer space S2.

[0076] At this time, the sealed fluid F present around the pressure generating end 13C is drawn into the dynamic pressure generating groove 13 by the negative pressure generated at and near the pressure generating end 13C, as shown by arrow H5'.

[0077] Thus, since the dynamic pressure generating groove 13 is equipped with inclined grooves 14 and reverse grooves 15 with different rotation directions for generating the main dynamic pressure, wear can be suppressed by separating the sliding surfaces 11 and 21 during both rotations, and leakage of the sealed fluid F from between the sliding surfaces 11 and 21 into the outer space S2 can be suppressed.

[0078] As explained above, the pressure generating end 13C is located on the same circumference as the reverse pressure generating end 13D on the sliding surface 11. With this arrangement, when the rotating sealing ring 20 rotates in the forward direction, the sealed fluid F sucked in by the reverse pressure generating end 13D moves toward the pressure generating end 13C located on the same circumference, making it easier to discharge the sealed fluid F sucked in by the reverse pressure generating end 13D from the pressure generating end 13C between the sliding surfaces 11 and 21.

[0079] Specifically, the dynamic pressure generating groove 13 does not have a surface that functions to move the flow that flows circumferentially from the reverse pressure generating end 13D to the pressure generating end 13C (see arrow L3 in Figure 4) toward the outer space S2 when the rotating sealing ring 20 is rotating in the forward direction. Therefore, it is easy to move the sealed fluid F sucked in at the reverse pressure generating end 13D toward the pressure generating end 13C.

[0080] Furthermore, when the rotating sealing ring 20 is rotating in the forward direction, the flow of air A flowing from the outer diameter side to the inner diameter side of the inclined groove 14 (see arrow L1 in Figure 4) and the flow of fluid flowing circumferentially from the reverse pressure generating end 13D to the pressure generating end 13C (see arrow L3 in Figure 4) are suppressed from interfering with each other near the pressure generating end 13C. In other words, flows L1 and L3 move in almost the same direction and merge, so that a stable positive pressure can be generated at the pressure generating end 13C.

[0081] Furthermore, since the reverse pressure generating end 13D is located on the inner space S1 side of the inclined groove 14, that is, at the closed end of the inclined groove 14, it is easy to generate positive pressure by the reverse groove 15 when the rotating sealing ring 20 rotates in the reverse direction.

[0082] Furthermore, since multiple dynamic pressure generating grooves 13 are arranged in the circumferential direction, and the pressure generating end 13C and the reverse pressure generating end 13D are located on the same circumference of the sliding surface 11, when the rotating sealing ring 20 is rotating in the forward direction, the sealed fluid F that flows out from the pressure generating end 13C between the sliding surfaces 11 and 21 can be easily recovered by the reverse pressure generating end 13D of another dynamic pressure generating groove 13 adjacent in the forward rotation direction.

[0083] Furthermore, when the rotating sealing ring 20 rotates in the reverse direction, the sealed fluid F that flows out from the reverse pressure generating end 13D between the sliding surfaces 11 and 21 can be easily recovered at the pressure generating end 13C of another dynamic pressure generating groove 13 adjacent in the reverse rotation direction.

[0084] Furthermore, since the pressure generating end 13C has an acute angle that tapers in the forward rotation direction when viewed axially, it is easier to converge the fluid in the dynamic pressure generating groove 13 when the rotating sealing ring 20 rotates in the forward direction, resulting in a high positive pressure generation effect at the pressure generating end 13C.

[0085] Furthermore, since the reverse pressure generating end 13D has a sharp angle that tapers in the reverse rotation direction when viewed axially, it is easier to converge the fluid in the dynamic pressure generating groove 13 when the rotating sealing ring 20 rotates in the reverse direction, resulting in a high positive pressure generation effect at the reverse pressure generating end 13D.

[0086] Furthermore, the wall portion 14b of the inclined groove 14 and the wall portion 15b of the reverse groove 15 are composed of a single arc-shaped wall portion 13a that extends circumferentially without having any bends. In other words, since the pressure generating end portion 13C and the reverse pressure generating end portion 13D are continuous with the same arc-shaped wall portion 13a, fluid can move smoothly between the pressure generating end portion 13C and the reverse pressure generating end portion 13D.

[0087] Furthermore, the sliding surface 11 is provided with a fluid introduction groove 16 that communicates with the internal space S1 and introduces the sealed fluid F, thereby improving the lubrication between the sliding surfaces 11 and 21 at low relative rotation speeds.

[0088] Furthermore, since the fluid introduction groove 16 has Rayleigh steps 18, 18' as dynamic pressure generating sections, the Rayleigh steps 18, 18' generate positive pressure, slightly separating the sliding surfaces 11, 21 and allowing the sealed fluid F to be introduced between the sliding surfaces 11, 21, thereby improving the lubrication between the sliding surfaces 11, 21.

[0089] Furthermore, since the outer diameter end 13A of the dynamic pressure generating groove 13 is in communication with the outer space S2, when rotating in the forward direction, the atmosphere A in the outer space S2 is easily introduced from the outer diameter end 13A, making it easier to generate positive pressure at the pressure generating end 13C by the atmosphere A, thereby enhancing the dynamic pressure effect.

[0090] Furthermore, since the inverted groove 15 has a shorter extension distance than the inclined groove 14, positive pressure can be generated earlier in the inverted groove 15 during reverse rotation. [Examples]

[0091] Next, the sliding component according to Embodiment 2 will be described with reference to Figure 6. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0092] In this embodiment 2, the stationary sealing ring 110, which serves as a sliding component, differs from the reverse groove 15 in the dynamic pressure generating groove 113 in the reverse groove 115 of embodiment 1, while the other configurations are the same as those of embodiment 1.

[0093] The reverse groove 115 consists of a bottom surface 115a that is flat in the direction of extension and parallel to the flat surface of the land 12, a side wall portion 115c that extends perpendicularly from the outer diameter side edge of the bottom surface 115a toward the flat surface of the land 12, and a wall portion 115b that extends perpendicularly from the inner diameter side edge of the bottom surface 115a toward the flat surface of the land 12.

[0094] The corner formed by the side wall portion 115c and the wall portion 115b, i.e., the reverse pressure generating end portion 113D, is approximately perpendicular in an axial view. [Examples]

[0095] Next, the sliding component according to Embodiment 3 will be described with reference to Figure 7. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0096] In this embodiment 3, the stationary sealing ring 210, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 213 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other components are the same as those of embodiment 1.

[0097] The dynamic pressure generating groove 213 has multiple reverse grooves 215 relative to the inclined groove 214. Specifically, the reverse grooves 215 extend in the reverse rotation direction from the side wall portion 214c in the reverse rotation direction of the inclined groove 214, and there are four of them spaced apart in the longitudinal direction of the inclined groove 214. These reverse pressure generating ends 213D taper in the reverse rotation direction and form an acute angle in the axial view. In addition, the inner diameter wall of the innermost reverse groove 215 is arranged on the same circumference as the inner diameter wall of the inclined groove 214 and smoothly connects with it.

[0098] According to this, when the rotating sealing ring 20 rotates in the reverse direction, positive pressure can be generated at each reverse pressure generating end 213D and its vicinity, so that a dynamic pressure effect can be obtained over substantially the entire radial direction, making it easier to separate the sliding surfaces.

[0099] Furthermore, when the rotating sealing ring 20 is rotating in the forward direction, the sealed fluid F at the reverse pressure generating end 213D of each reverse groove 215 and its vicinity can be sucked in and recovered into the dynamic pressure generating groove 213.

[0100] Furthermore, as a modified example 3-1 of the dynamic pressure generating groove 213 in this embodiment 3, as shown in Figure 8, the reverse pressure generating end 2131D of the dynamic pressure generating groove 2131 has a substantially rectangular shape in an axial view.

[0101] According to this, by providing multiple reverse pressure generating ends 2131D in the radial direction, a dynamic pressure effect can be obtained over substantially the entire radial direction when the rotating sealing ring 20 rotates in the reverse direction, making it easier to separate the sliding surfaces.

[0102] Furthermore, as a modification 3-2 of the dynamic pressure generating groove 213 of the above embodiment 3, as shown in Figure 9, the reverse pressure generating end 2132D of the dynamic pressure generating groove 2132 tapers in the direction of reverse rotation and in the inward diameter direction.

[0103] More specifically, the side wall portion 2142c of the dynamic pressure generating groove 2132 is composed of an outer diameter portion 2142e and an inner diameter portion 2142f.

[0104] The outer diameter portion 2142e extends in a roughly semicircular arc shape, inclined toward the positive rotational direction from the outer diameter side toward the inner diameter side.

[0105] The inner diameter portion 2142f has a shape in which arc-shaped surfaces, which are convex in the forward rotation direction and outward direction when viewed axially, are continuous in the radial direction. The ends of adjacent arc-shaped surfaces form the reverse pressure generating ends 2132D.

[0106] According to this, by providing multiple reverse pressure generating ends 2132D in the radial direction, a dynamic pressure effect can be obtained over substantially the entire radial direction when the rotating sealing ring 20 rotates in the reverse direction, making it easier to separate the sliding surfaces. In addition, since the reverse pressure generating ends 2132D are oriented in the inward radial direction, it is easier to push the sealed fluid F back to the inward side, improving the sealing performance when the rotating sealing ring 20 rotates in the reverse direction.

[0107] Furthermore, as a modification 3-3 of the dynamic pressure generating groove 213 of the above embodiment 3, as shown in Figure 10, the reverse pressure generating end 2133D of the dynamic pressure generating groove 2133 tapers in the direction of reverse rotation and in the inward diameter direction, forming a roughly triangular shape in axial view.

[0108] The side wall portion 2143c of the dynamic pressure generating groove 2133 is composed of an outer diameter portion 2143e and an inner diameter portion 2143f.

[0109] The outer diameter portion 2143e extends in an arc shape, inclined in the forward rotational direction from the outer diameter side towards the inner diameter side.

[0110] The inner diameter portion 2143f has a zigzag shape, or so-called sawtooth shape, in which peaks that are convex in the forward rotation direction and outward diameter direction when viewed axially are continuous in the radial direction. In other words, the radial direction of the dynamic pressure generating groove 2133 has multiple narrow portions 2133E in which the width in the circumferential direction is narrowed. In addition, the valleys of the inner diameter portion 2143f serve as the reverse pressure generating ends 2133D.

[0111] According to this, when the rotating sealing ring 20 is rotating in the forward direction, the multiple narrow sections 2133E provided in the radial direction of the dynamic pressure generating groove 2133 make it easy to generate positive pressure from the atmosphere A.

[0112] Furthermore, by providing multiple reverse pressure generating ends 2133D in the radial direction, a dynamic pressure effect can be obtained over substantially the entire radial direction when the rotating sealing ring 20 rotates in the reverse direction, making it easier to separate the sliding surfaces. In addition, since the reverse pressure generating ends 2133D are oriented in the inward radial direction, it is easier to push the sealed fluid F back towards the inward side, improving the sealing performance when the rotating sealing ring 20 rotates in the reverse direction.

[0113] Furthermore, as a modification 3-4 of the dynamic pressure generating groove 213 of the above embodiment 3, as shown in Figure 11, the reverse pressure generating end 2134D of the dynamic pressure generating groove 2134 tapers in the direction of reverse rotation and in the inward diameter direction, forming a roughly triangular shape in axial view.

[0114] The side wall portion 2144c of the dynamic pressure generating groove 2134 is composed of an outer diameter portion 2144e and an inner diameter portion 2144f.

[0115] The outer diameter portion 2144e extends in an arc shape, inclined in the forward rotational direction from the outer diameter side towards the inner diameter side.

[0116] The inner diameter portion 2144f has a zigzag shape, or so-called sawtooth shape, in which peaks that are convex in the direction of reverse rotation and in the inner diameter when viewed axially are continuous in the radial direction. The peaks of the inner diameter portion 2144f serve as the reverse pressure generating end 2134D. In other words, the circumferential width of the dynamic pressure generating groove 2134 is expanded by the reverse pressure generating end 2134D.

[0117] According to this, by providing multiple reverse pressure generating ends 2134D in the radial direction, a dynamic pressure effect can be obtained over substantially the entire radial direction when the rotating sealing ring 20 rotates in the reverse direction, making it easier to separate the sliding surfaces. In addition, since the reverse pressure generating ends 2134D are oriented in the inward radial direction, it is easier to push the sealed fluid F back to the inward side, improving the sealing performance when the rotating sealing ring 20 rotates in the reverse direction.

[0118] Furthermore, as a modification 3-5 of the dynamic pressure generating groove 213 of the above embodiment 3, as shown in Figure 12, the reverse pressure generating end 2135D of the dynamic pressure generating groove 2135 has a substantially arc shape that forms a convex ridge in the reverse rotation direction and in the inner diameter direction when viewed in the axial direction.

[0119] According to this, by providing multiple reverse pressure generating ends 2135D in the radial direction, a dynamic pressure effect can be obtained over substantially the entire radial direction when the rotating sealing ring 20 rotates in the reverse direction, making it easier to separate the sliding surfaces.

[0120] In addition, in Example 3 and Modifications 3-1 to 3-5, the number of reverse pressure generating ends can be freely set. Furthermore, the reverse pressure generating ends may be provided along the entire length of the side wall on the reverse rotation side of the dynamic pressure generating groove. [Examples]

[0121] Next, the sliding component according to Embodiment 4 will be described with reference to Figure 13. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0122] In this embodiment 4, the stationary sealing ring 310, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 313 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other components are the same as those of embodiment 1.

[0123] In the inclined groove 314 of the dynamic pressure generating groove 313, the inner diameter end of the side wall portion 314d in the forward rotation direction is further provided with a side wall portion 314d' that is inclined in the inward direction and extends in the inward direction. The angle of the bend formed by the side wall portion 314d and the side wall portion 314d' is greater than 90 degrees and less than 180 degrees.

[0124] The side wall portion 314d' and the arc-shaped wall portion 313a form a pressure generating end portion 313C that forms an acute angle in an axial view.

[0125] The pressure generating end 313C and the reverse pressure generating end 313D of the dynamic pressure generating groove 313 are positioned on opposite sides in the circumferential direction, separated by a virtual line α that extends radially through the bent portion formed by the side wall portion 314d and the side wall portion 314d'.

[0126] According to this, when the rotating sealing ring 20 rotates in the forward direction, the air A flowing through the inclined groove 314 is guided in the radial direction by the side wall portion 314d', so that, as shown by arrow L10, the air A discharged from the pressure generating end portion 313C between the sliding surfaces can efficiently push back the sealed fluid F between the sliding surfaces towards the inner space S1. [Examples]

[0127] Next, the sliding parts according to Example 5 will be described with reference to Figure 14. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0128] In this embodiment 5, the stationary sealing ring 410, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 413 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other configurations are the same as those of embodiment 1.

[0129] The dynamic pressure generating groove 413 has its pressure generating end 413C positioned closer to the inner space S1 than its reverse pressure generating end 413D. The arc-shaped wall portion 413a extends in an arc shape, inclined in the forward rotation direction of the rotating sealing ring 20, from the reverse pressure generating end 413D, which is located relatively closer to the outer space S2, towards the pressure generating end 413C, which is located relatively closer to the inner space S1.

[0130] According to this, when the rotating sealing ring 20 is rotating in the forward direction, the fluid flow L20 flowing from the outer diameter side to the inner diameter side of the dynamic pressure generating groove 413 and the fluid flow L21 flowing from the reverse pressure generating end 413D to the pressure generating end 413C do not interfere with each other. In other words, flows L20 and L21 move in the same direction, so that a stable positive pressure can be generated at the pressure generating end 413C. [Examples]

[0131] Next, the sliding component according to Embodiment 6 will be described with reference to Figure 15. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0132] In this embodiment 6, the stationary sealing ring 510, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 513 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other components are the same as those of embodiment 1.

[0133] The dynamic pressure generating groove 513 has a narrow section 513E located on the outer diameter side of the pressure generating end 513C and the reverse pressure generating end 513D. More specifically, the inner diameter side portion 515f of the side wall portion 515c of the dynamic pressure generating groove 513 is formed in a stepped shape so that it is positioned in the forward rotation direction more than the outer diameter side portion 515e.

[0134] According to this, since the dynamic pressure generating groove 513 is provided with a narrow section 513E, when the rotating sealing ring 20 rotates in the forward direction, atmospheric air A can be efficiently collected at the pressure generating end 513C compared to a dynamic pressure generating groove with a constant width in the extending direction, making it easier to generate positive pressure at the pressure generating end 513C due to the atmospheric air A.

[0135] Furthermore, when the rotating sealing ring 20 rotates in the reverse direction, the reverse pressure generating end 513D generates positive pressure, which can cause the sliding surfaces to separate.

[0136] Furthermore, as a modification 6-1 of the dynamic pressure generating groove 513 of the above embodiment 6, the dynamic pressure generating groove 5131 is provided with a narrow section 5131E, as shown in Figure 16. In addition, the reverse pressure generating end 5131D of the dynamic pressure generating groove 5131 is substantially rectangular in an axial view.

[0137] According to this, the dynamic pressure generating groove 5131, due to its narrow section 5131E, easily generates positive pressure from the atmosphere A at the pressure generating end 5131C when the rotating sealing ring 20 is rotating in the forward direction. Furthermore, when the rotating sealing ring 20 is rotating in the reverse direction, it generates positive pressure at the reverse pressure generating end 5131D, which can separate the sliding surfaces.

[0138] Furthermore, as a modification 6-2 of the dynamic pressure generating groove 513 of the above embodiment 6, the dynamic pressure generating groove 5132 is provided with a narrow section 5132E, as shown in Figure 17. Specifically, the radial central portion of the side wall portion 5152c of the dynamic pressure generating groove 5132 is formed in an axial view that is roughly mountain-shaped, with a convexity in the forward rotation direction.

[0139] According to this, the dynamic pressure generating groove 5132, due to its narrow section 5132E, easily generates positive pressure from the atmosphere A at the pressure generating end 5132C when the rotating sealing ring 20 is rotating in the forward direction. Furthermore, when the rotating sealing ring 20 is rotating in the reverse direction, it generates positive pressure at the reverse pressure generating end 5132D, which can separate the sliding surfaces.

[0140] Furthermore, as a modification 6-3 of the dynamic pressure generating groove 513 of the above embodiment 6, as shown in Figure 18, the dynamic pressure generating groove 5133 is provided with a narrow section 5133E. Specifically, the inner diameter portion of the side wall portion 5153c of the dynamic pressure generating groove 5133 is formed in an axial view that is convex in the forward rotation direction, with a roughly mountain shape.

[0141] According to this, the dynamic pressure generating groove 5133, due to its narrow section 5133E, easily generates positive pressure from the atmosphere A at the pressure generating end 5133C when the rotating sealing ring 20 is rotating in the forward direction. Furthermore, when the rotating sealing ring 20 is rotating in the reverse direction, it generates positive pressure at the reverse pressure generating end 5133D, which can separate the sliding surfaces. [Examples]

[0142] Next, the sliding component according to Embodiment 7 will be described with reference to Figure 19. Note that the description of components that are identical to those in Embodiment 1 and therefore redundant will be omitted.

[0143] In this embodiment 7, the stationary sealing ring 610, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 613 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other components are the same as those of embodiment 1.

[0144] The dynamic pressure generating groove 613 is formed in an arc shape where the bent portion between the side wall portion 614d and the inner diameter side wall portion 613a, i.e., the pressure generating end portion 613C, is convex in the forward rotation direction when viewed axially. [Examples]

[0145] Next, the sliding component according to Example 8 will be described with reference to Figure 20. Note that the description of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0146] In this embodiment 8, the stationary sealing ring 710, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 713 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other components are the same as those of embodiment 1.

[0147] The reverse pressure generating end 713D in the dynamic pressure generating groove 713 is formed by a side wall portion 715c extending in the reverse rotation direction and toward the inner space S1 from the inner diameter side wall portion 714c on the reverse rotation side, a wall portion 715b extending in the reverse rotation direction and toward the outer space S2 from the reverse rotation direction end of the inner diameter side wall portion 713a, and a bottom surface 715a.

[0148] According to this, the inclination of the wall portion 715b and the side wall portion 714d can be made to be in approximately the same direction, so that adjacent dynamic pressure generating grooves 713 in the circumferential direction can be efficiently arranged closer together in the circumferential direction. [Examples]

[0149] Next, the sliding component according to Example 9 will be described with reference to Figure 21. Note that the description of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0150] In this embodiment 9, the stationary sealing ring 810, which serves as a sliding component, has a different shape for the dynamic pressure generating groove 813 compared to the dynamic pressure generating groove 13 of embodiment 1, but the other components are the same as those of embodiment 1.

[0151] The pressure generating end 813C of the dynamic pressure generating groove 813 is formed by a forward-rotating side wall portion 814d, an inner diameter side wall portion 813a, and a bottom surface 814a. The inner diameter side wall portion 813a extends substantially linearly along the circumferential direction.

[0152] The reverse pressure generating end 813D in the dynamic pressure generating groove 813 is formed by a side wall portion 815c extending in the reverse rotation direction and toward the inner space S1 from the inner diameter side wall portion 814c on the reverse rotation side, a wall portion 815b extending in the reverse rotation direction and toward the inner space S1 from the reverse rotation direction end of the inner diameter side wall portion 813a, and a bottom surface 815a.

[0153] In other words, the reverse pressure generating end 813D is positioned closer to the inner space S1 than the pressure generating end 813C. Furthermore, the reverse pressure generating end 813D is oriented in the reverse rotation direction and in the inner diameter direction.

[0154] The pressure generating end 813C and the reverse pressure generating end 813D are not continuous on one of the surfaces facing the internal space S1. In other words, a bent portion is formed between the inner diameter side wall portion 813a and the wall portion 815b.

[0155] According to this, when the rotating sealing ring 20 rotates in the forward direction, the sealed fluid F sucked in from the reverse pressure generating end 813D moves along the wall portion 815b and then along the inner diameter side wall portion 813a. As a result, it does not interfere with the flow of air A flowing through the inclined groove 814 and is easily discharged between the sliding surfaces by the flow of air A.

[0156] Furthermore, since the reverse pressure generating end 813D is oriented in the reverse rotation direction and in the inward direction, it is easier to push the sealed fluid F back towards the inward side when the rotating sealing ring 20 rotates in the reverse direction, and the sliding surfaces can be separated. [Examples]

[0157] Next, the sliding parts of Example 10 will be described with reference to Figure 22. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0158] In this embodiment 10, the stationary sealing ring 910, which serves as a sliding component, has multiple sets of dynamic pressure generating grooves 9131 to 9134 arranged in the circumferential direction. The dynamic pressure generating grooves 9131 to 9134 have the same extending length.

[0159] The dynamic pressure generating groove 9131 has almost the same configuration as the dynamic pressure generating groove 13 in Example 1.

[0160] The dynamic pressure generating groove 9132 is arranged adjacent to the dynamic pressure generating groove 9131 in the opposite direction of rotation. The pressure generating end 9132C is arranged on the same circumference as the pressure generating end 9131C of the dynamic pressure generating groove 9131. The reverse pressure generating end 9132D is arranged on the outer diameter side of the reverse pressure generating end 9131D of the dynamic pressure generating groove 9131.

[0161] The dynamic pressure generating groove 9133 is positioned adjacent to the dynamic pressure generating groove 9132 in the opposite direction of rotation. The pressure generating end 9133C is positioned on the same circumference as the pressure generating end 9131C of the dynamic pressure generating groove 9131. The reverse pressure generating end 9133D is positioned on the outer diameter side of the reverse pressure generating end 9132D of the dynamic pressure generating groove 9132.

[0162] The dynamic pressure generating groove 9134 is positioned adjacent to the dynamic pressure generating groove 9133 in the opposite direction of rotation. The pressure generating end 9134C is positioned on the same circumference as the pressure generating end 9131C of the dynamic pressure generating groove 9131. The reverse pressure generating end 9134D is positioned on the outer diameter side of the reverse pressure generating end 9133D of the dynamic pressure generating groove 9133.

[0163] In other words, the reverse pressure generating ends 9131D to 9134D are radially offset from each other.

[0164] Furthermore, corners 9132F to 9134F are formed on the reverse rotation direction side of the inner diameter ends of the dynamic pressure generating grooves 9132 to 9134, and a small amount of reverse pressure can also be generated at these corners 9132F to 9134F. [Examples]

[0165] Next, the sliding parts according to Example 11 will be described with reference to Figure 23. Note that descriptions of components that are identical to those in Example 1 and therefore redundant will be omitted.

[0166] The mechanical seal in this embodiment 11 is an inside type that seals the fluid to be sealed F that is about to leak from the outer space S2 towards the inner space S1, and the inner space S1 is open to the atmosphere A.

[0167] In this embodiment 11, the stationary sealing ring 1010, which serves as a sliding component, has multiple dynamic pressure generating grooves 1013 and fluid introduction grooves 1016 provided circumferentially on its sliding surface 1011. Note that the dynamic pressure generating grooves 1013 and fluid introduction grooves 1016 are configured by reversing the radial direction of the dynamic pressure generating grooves 13 and fluid introduction grooves 16 of Embodiment 1, so a detailed explanation is omitted.

[0168] As described above, the sliding parts of the present invention have been explained with examples 1 to 11, modifications 3-1 to 3-5, and modifications 6-1 to 6-3 as illustrations. However, as shown in Figures 24(a) and 24(b), if the dynamic pressure generating groove is merely an inclined groove, that is, if it does not have a reverse pressure generating end extending in the reverse direction from the opposite side of the inclined groove in the reverse rotation direction, it does not qualify as a sliding part of the present invention.

[0169] Furthermore, as shown in Figures 24(c) and 24(d), in a dynamic pressure generating groove where all or part of the reverse pressure generating end, which is substantially rectangular when viewed from the axial direction, is located in a space on the sealed fluid side of the positive pressure generating end, a case where the wall portion on the forward rotation side constituting the reverse pressure generating end also serves as the wall portion of the positive pressure generating end, i.e., where the reverse pressure generating end extends from the forward rotation side of the inclined groove in the reverse rotation direction, does not qualify as a sliding part of the present invention. In such a dynamic pressure generating groove, the fluid flow in the reverse groove is not sufficiently discharged to the sealed fluid side by the fluid in the inclined groove during forward rotation, which may result in less effective sealing than in the present invention.

[0170] 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.

[0171] For example, in the above embodiments 1 to 11, automotive mechanical seals were used as examples of sliding parts, but other mechanical seals such as those used in general industrial machinery 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.

[0172] Furthermore, while the above-described examples 1 to 11 described an example in which the dynamic pressure generating groove and fluid introduction groove are provided on a stationary sealing ring, the dynamic pressure generating groove and fluid introduction groove may also be provided on a rotating sealing ring.

[0173] Furthermore, in Examples 1 to 11, the sealed fluid side was described as the high-pressure side and the leak side as the low-pressure side. However, the sealed fluid side may be the low-pressure side and the leak side may be the high-pressure side, or the sealed fluid side and the leak side may be at approximately the same pressure.

[0174] Furthermore, although it was explained in Examples 1 to 11 that the inclined grooves in the dynamic pressure generating grooves are in communication with the leakage space, this is not limited to this, and they do not need to be in communication as long as dynamic pressure can be generated.

[0175] Furthermore, while the above-described embodiments 1 to 8, 10, and 11 illustrate a configuration in which the pressure generating end and the reverse pressure generating end are continuous by an arc-shaped wall, the embodiment is not limited to this, and they may be continuous by a flat surface that is linear in an axial view. In addition, the surface continuous between the pressure generating end and the reverse pressure generating end may have steps or bends in the circumferential direction, as in embodiment 9, but it is preferable that it does not have steps or bends.

[0176] Furthermore, while embodiments 1 to 11 illustrate a configuration in which reverse grooves are formed in all dynamic pressure generating grooves, a mixture of dynamic pressure generating grooves with reverse grooves and those without reverse grooves is also possible. Dynamic pressure generating grooves with reverse grooves are preferably located near the ends of the Rayleigh step because they can recover the sealed fluid between the sliding surfaces and return it to the sliding surfaces.

[0177] Furthermore, while embodiments 1 to 11 illustrate a configuration in which the fluid introduction groove communicates with the sealed fluid space, the invention is not limited to this configuration. It does not need to communicate with the fluid space as long as it can store the sealed fluid, for example, it could be a dimple or the like.

[0178] Furthermore, while embodiments 1 to 11 illustrate a configuration in which the fluid introduction groove has a Rayleigh step, the invention is not limited to this configuration. Any configuration that can generate dynamic pressure is acceptable. For example, the dynamic pressure generating section may be an inclined groove that is inclined in the circumferential direction and extends radially. The configuration of the dynamic pressure generating section may also be omitted.

[0179] Furthermore, while embodiments 1 to 11 illustrate configurations in which multiple fluid introduction grooves are provided in the circumferential direction, it is sufficient to provide at least one. The configuration of the fluid introduction grooves may also be omitted.

[0180] Furthermore, although the sealed fluid F was described as a high-pressure liquid in Examples 1 to 11, it is not limited to this and may be a gas or a low-pressure liquid, or it may be a mist-like mixture of liquid and gas.

[0181] Furthermore, although the leakage fluid in Examples 1 to 11 was described as atmospheric air A, which is a low-pressure gas, it is not limited to this and may be a liquid or a high-pressure gas, or it may be a mist-like mixture of liquid and gas. [Explanation of Symbols]

[0182] 10. Stationary sealing ring (sliding part) 11 Sliding surface 13 Dynamic pressure generating groove 13C Pressure generating end (first dynamic pressure generating end) 13D Reverse pressure generation end (second dynamic pressure generation end) 13a Arc-shaped wall portion (arc-shaped surface) 14 Slant groove 14a Base 14b Wall section 14c Side wall part 14d Side wall part 15 Reverse groove 15a Bottom 15b Wall section 15c Side wall part 16 Fluid inlet groove (fluid inlet / outlet groove) 17 Fluid guide groove 18,18' Rayleigh step (dynamic pressure generation section) 20 Rotating sealing ring (other sliding parts) 21 Sliding surface A atmosphere F Sealed fluid S1 Inner space (sealed fluid space) S2 External space (leakage space)

Claims

1. A sliding component comprising a pair of sliding rings that rotate relative to each other, thereby separating a sealed fluid space from a leak space, The aforementioned sliding component has a dynamic pressure generating groove that generates dynamic pressure, The dynamic pressure generating groove is An inclined groove extending in a forward rotational direction from the leakage space toward the sealed fluid space and having a first dynamic pressure generating end, The sliding component comprises a reverse groove extending in the reverse rotation direction from the reverse rotation direction side of the inclined groove and having a second dynamic pressure generating end, wherein the surface of the inclined groove on the side of the sealed fluid space is arranged on the same circumference.

2. The second dynamic pressure generating end extends from the closed end of the inclined groove, The sliding component according to claim 1, wherein the first dynamic pressure generating end is arranged on the same circumference as the second dynamic pressure generating end.

3. A sliding component comprising a pair of sliding rings that rotate relative to each other, thereby separating a sealed fluid space from a leak space, The aforementioned sliding component has a dynamic pressure generating groove that generates dynamic pressure, The dynamic pressure generating groove is An inclined groove extending in a forward rotational direction from the leakage space toward the sealed fluid space and having a first dynamic pressure generating end, A sliding component comprising: a reverse groove extending in the reverse rotation direction from the reverse rotation direction side of the inclined groove and having a second dynamic pressure generating end, wherein the first dynamic pressure generating end is located on the sealed fluid space side of the second dynamic pressure generating end.

4. The sliding component according to claim 1, wherein the first dynamic pressure generating end is located on the leakage space side of the second dynamic pressure generating end.

5. The sliding part according to any one of claims 1 to 4, wherein the surfaces of the first dynamic pressure generating end and the second dynamic pressure generating end facing the sealed fluid space are connected by the same plane.

6. The sliding component according to claim 1, wherein the surfaces of the first dynamic pressure generating end and the second dynamic pressure generating end facing the sealed fluid space are continuous by the same arc-shaped surface.

7. The sliding component according to claim 1, wherein the first dynamic pressure generating end forms an acute angle in an axial view.

8. The sliding component according to claim 1, wherein the first dynamic pressure generating end tapers in the forward rotation direction and its tip has a curved surface.

9. The sliding component according to claim 1, wherein the second dynamic pressure generating end forms an acute angle in an axial view.

10. The sliding component according to claim 1, wherein the second dynamic pressure generating end tapers in the reverse rotation direction and its tip has a curved surface.

11. The sliding component according to claim 1, further comprising a fluid outlet / inlet groove that communicates with the sealed fluid space.

12. The sliding component according to claim 11, wherein the fluid outlet / inlet groove is provided with a dynamic pressure generating section.

Images