Sliding parts

Abstract

Provided is a sliding component capable of suppressing leakage of a sealed fluid to a leakage side.　Provided is a ring-shaped sliding component 10 that is disposed at a location on a rotary machine where relative rotation is performed and that slides relative to another sliding component 20. The sliding component 10 includes, on a sliding surface 11 thereof, negative pressure-generating shallow grooves 9 that extend in the circumferential direction, and a deep groove 15 that recovers a sealed fluid F in the shallow grooves 9 and that is deeper than the shallow grooves 9. The shallow grooves 9 are arranged on both sides of the deep groove 15 in the circumferential direction, and a communication groove 16 that communicates the shallow grooves on both sides in the circumferential direction is provided further to the leakage side than a leakage side end part 15A of the deep groove 15.

Description

[Technical Field]

[0001] The present invention relates to a sliding part that rotates relative to another sliding part, such as a sliding part used in a shaft sealing device that seals the rotating shaft of a rotating machine in an automobile, general industrial machine, or other sealing field, or a sliding part used in a bearing of a machine in an automobile, general industrial machine, or other bearing field. [Background technology]

[0002] Mechanical seals, for example, are shaft sealing devices that prevent leakage of sealed fluids. They include a pair of annular sliding elements that rotate relative to one another and slide against each other. In recent years, there has been a demand for reducing the energy lost due to sliding in such mechanical seals, due to environmental concerns and other factors. To address this issue, some mechanical seals have a positive pressure generating groove on the sliding element that communicates with the outer diameter side, which is the high-pressure sealed fluid side, and has one end closed on the sliding element. In this configuration, when the sliding elements rotate relative to one another, positive pressure is generated in the positive pressure generating groove, separating the sliding surfaces. Furthermore, the sealed fluid is introduced from the outer diameter side into the positive pressure generating groove, which retains the sealed fluid, improving lubrication and achieving low friction.

[0003] Furthermore, in order to maintain sealing performance over the long term, mechanical seals must be able to provide both lubrication and sealing. For example, in the mechanical seal disclosed in Patent Document 1, one of the sliding components has a Rayleigh step and an inverse Rayleigh step that communicate with the sealed fluid. According to this, during relative rotation of the sliding components, the Rayleigh step generates positive pressure between the sliding surfaces, separating them. The presence of the sealed fluid between the sliding surfaces improves lubrication. Meanwhile, the inverse Rayleigh step generates a relative negative pressure, and since the inverse Rayleigh step is located closer to the leakage side than the Rayleigh step, the high-pressure sealed fluid that flows out from the Rayleigh step between the sliding surfaces can be sucked into the inverse Rayleigh step. Furthermore, a deep groove with a larger volume than the inverse Rayleigh step is provided at the end of the relative rotation of the inverse Rayleigh step. The sealed fluid recovered by the inverse Rayleigh step is returned to the sealed fluid side via the deep groove. In this way, the sealed fluid between the pair of sliding components is prevented from leaking to the leakage side, improving sealing performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 046749 (pages 14-16, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0005] In the sliding element disclosed in Patent Document 1, the end of the relative rotation of the inverse Rayleigh step is connected to the deep groove, and the start of the relative rotation of the inverse Rayleigh step is positioned close to one circumferential side of the deep groove, so that the sealed fluid that has flowed out from the Rayleigh step between the sliding surfaces can be collected over almost the entire circumference of the sliding surfaces. However, during relative rotation of the sliding element, the sealed fluid may flow out locally between the sliding surfaces from the end of the deep groove on the leakage side, and there is a risk that the sealed fluid that has flowed out from the deep groove between the sliding surfaces will leak to the leakage side.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a sliding component that can suppress leakage of the sealed fluid to the leakage side. [Means for solving the problem]

[0007] In order to solve the above problems, the sliding component of the present invention comprises: An annular sliding component that is arranged at a relatively rotating portion of a rotary machine and slides relative to other sliding components, a sliding surface of the sliding element is provided with a shallow groove extending in a circumferential direction for generating a negative pressure, and a deep groove deeper than the shallow groove for recovering the sealed fluid in the shallow groove, The shallow grooves are disposed on both sides of the deep groove in the circumferential direction, A communication groove is provided on the leakage side of the leakage side end of the deep groove, which communicates the shallow grooves on both sides in the circumferential direction. With this, the sealed fluid that flows out from the leakage side end of the deep groove toward the leakage side during relative rotation of the sliding parts can be collected by the communicating groove, thereby suppressing leakage of the sealed fluid toward the leakage side.

[0008] The communication groove may be provided away from the leakage side end of the deep groove. This makes it easier to maintain a negative pressure in the communication groove, and the ability of the communication groove to recover the sealed fluid can be maintained.

[0009] The communicating groove may be formed to the same depth as the shallow groove. This facilitates the generation of negative pressure in the communicating groove during relative rotation of the sliding parts, thereby enhancing the ability of the communicating groove to recover the sealed fluid. Furthermore, since no step is formed between the communicating groove and the shallow groove, it is possible to prevent positive pressure from being generated between the communicating groove and the shallow groove.

[0010] The communicating groove may be formed to be narrower than the shallow groove. This allows the volume of the communicating groove to be reduced, so that the communicating groove is less likely to affect the negative pressure generating function of the shallow groove.

[0011] The communication groove may have a curved shape that is convex toward the leakage side. This allows the overall length of the communicating groove to be shortened while ensuring the separation distance between the communicating groove and the deep groove.

[0012] The communicating groove may have a symmetrical shape with respect to a line extending in a radial direction and passing through the deep groove. This allows negative pressure to be generated in the same manner in the communicating groove in any rotation direction of the sliding element.

[0013] The shallow groove may extend around the entire circumference of the sliding surface of the sliding element, and may have a start end and an end end that are continuous with the deep groove in the circumferential direction. This allows negative pressure to be generated around the entire circumference of the sliding surface of the sliding component, and also prevents positive pressure from being generated between the sliding surfaces by the shallow groove, since the sealed fluid at the end of the shallow groove flows into the deep groove.

[0014] The shallow groove of the sliding component according to the present invention extending in the circumferential direction means that the shallow groove extends with at least a circumferential component, preferably so that the circumferential component is larger than the radial component, and the deep groove extends in the radial direction means that the deep groove extends with at least a radial component, preferably so that the radial component is larger than the circumferential component.

[0015] The sealed fluid may be gas or liquid, or may be a mist of a mixture of liquid and gas. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a vertical cross-sectional view showing an example of a mechanical seal according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a view of the sliding surface of the stationary seal ring as viewed from the axial direction. [Figure 3]2. (a) is a cross-sectional view taken along line AA in FIG. 2, (b) is a cross-sectional view taken along line BB, and (c) is a cross-sectional view taken along line CC in FIG. [Figure 4] FIG. 10 is an explanatory diagram of the vicinity of a liquid guide groove in the negative pressure generating mechanism as viewed from the axial direction. [Figure 5] FIG. 10 is a view of the sliding surface of the stationary seal ring according to the second embodiment of the present invention, as viewed from the axial direction. [Figure 6] FIG. 10 is a view of the sliding surface of a stationary seal ring according to a third embodiment of the present invention, as viewed from the axial direction. [Figure 7] FIG. 4 is an explanatory view showing a modified example of the mechanical seal in Examples 1 to 3. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sliding element according to an embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0018] A sliding component according to a first embodiment will be described with reference to Figs. 1 to 4. In this embodiment, the sliding component will be described as a mechanical seal. The outer diameter side of the sliding component constituting the mechanical seal will be described as the sealed fluid side (high-pressure side), and the inner diameter side will be described as the atmosphere side (low-pressure side) that serves as the leakage side. For ease of explanation, grooves and the like formed on the sliding surface may be indicated by dots in the drawings.

[0019] The mechanical seal for general industrial machinery shown in Fig. 1 is an inside type that seals against a sealed fluid F that tends to leak from the outer diameter side to the inner diameter side of the sliding surface. In this embodiment, the sealed fluid F is a high-pressure gas.

[0020] The mechanical seal is mainly composed of a rotary seal ring 20, which is an annular sliding part mounted on a rotating shaft 1 via a sleeve 2 so as to be rotatable integrally with the rotating shaft 1, and a circular stationary seal ring 10, which is a sliding part mounted in a non-rotating state but axially movable state on a seal cover 5 fixed to a housing 4 of the device to which the seal is attached, and the static seal ring 10 is axially biased by a bellows 7, so that the sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotary seal ring 20 slide closely against each other. The sliding surface 21 of the rotary seal ring 20 is flat, and this flat surface does not have any recesses.

[0021] The stationary seal ring 10 and the rotating seal ring 20 are typically formed from a combination of SiC (hard material) or SiC (hard material) and carbon (soft material), but any sliding material used for mechanical seals can be used. Examples of SiC include sintered bodies using boron, aluminum, carbon, or other sintering aids, as well as materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC consisting of SiC and Si, SiC-TiC, and SiC-TiN. Examples of carbon include a mixture of carbonaceous and graphite materials, resin-molded carbon, and sintered carbon. In addition to the above sliding materials, metal materials, resin materials, surface-modified materials (coating materials), composite materials, and other materials are also applicable.

[0022] 2, the rotary seal ring 20 slides relative to the stationary seal ring 10 as shown by the arrow. A negative pressure generating mechanism 14 is provided on the sliding surface 11 of the stationary seal ring 10.

[0023] The negative pressure generating mechanism 14 includes a fluid guide groove 15 as a deep groove, a shallow groove 9 for generating negative pressure, and a communicating groove 16. The fluid guide groove 15 extends in the radially inner direction and communicates with the space on the sealed fluid F side. The shallow groove 9 extends in the circumferential direction from the downstream circumferential end of the fluid guide groove 15 on the radially inner side concentrically with the stationary seal ring 10 and is connected to the upstream circumferential end of the fluid guide groove 15 on the radially inner side. The communicating groove 16 connects the starting end 9a and the terminal end 9b of the shallow groove 9.

[0024] The portions of the sliding surface 11 other than the negative pressure generating mechanism 14 are lands 12a, 12b, and 12c forming flat end surfaces. Although not shown, it is preferable that a positive pressure generating mechanism such as a dimple is formed on the land 12a located on the outer diameter side of the shallow groove 9.

[0025] Next, an outline of the negative pressure generating mechanism 14 will be explained with reference to Figures 2 and 3. In the following explanation, in Figure 2, the end of the shallow groove 9 connected to the left side of the fluid guide groove 15 as viewed in the drawing will be referred to as the starting end 9a of the relative rotation of the shallow groove 9, i.e., the upstream side of the sealed fluid F flowing in the shallow groove 9, and the end of the shallow groove 9 connected to the right side of the fluid guide groove 15 as the ending end 9b of the relative rotation of the shallow groove 9, i.e., the downstream side of the sealed fluid F flowing in the shallow groove 9. Furthermore, for the sake of convenience of explanation, the shallow groove 9 and the communicating groove 16 are shown to be deeper than they actually are.

[0026] The fluid guide groove 15 in the first embodiment extends in the radial direction of the stationary seal ring 10. The fluid guide groove 15 and the starting end 9a and terminal end 9b of the shallow groove 9 are connected to each other, i.e., arranged side by side in the circumferential direction. The shallow groove 9 has a bottom surface 9c, an outer side surface 9d extending from the outer diameter side of the bottom surface 9c, and an inner side surface 9e extending from the inner diameter side of the bottom surface 9c. The outer side surface 9d and the inner side surface 9e are parallel to each other and perpendicular to the flat end surfaces formed by the lands 12a, 12b, and 12c. The inner side surface 9e and the inner diameter side end surface 15a of the fluid guide groove 15 are continuous and flush with each other in the circumferential direction.

[0027] As shown in Fig. 3(a), the bottom surface 9c extends such that both circumferential ends, i.e., both ends on the fluid guiding groove 15 side, gradually become shallower toward the fluid guiding groove 15. That is, the communication ports between the starting end 9a of the shallow groove 9 and the fluid guiding groove 15 and between the ending end 9b of the shallow groove 9 and the fluid guiding groove 15 are constricted. In addition, portions of the bottom surface 9c other than the ends on the fluid guiding groove 15 side are flat surfaces parallel to the flat end surfaces formed by the lands 12a, 12b, and 12c.

[0028] Returning to Fig. 2, the communication groove 16 is formed to connect positions near the upstream side and the downstream side of the end face 15a of the fluid guiding groove 15 on the inner side surface 9e of the shallow groove 9. The communication groove 16 is provided away from the inner diameter side end 15A of the fluid guiding groove 15 toward the inner diameter side. That is, a land 12b is formed between the fluid guiding groove 15 and the communication groove 16.

[0029] Specifically, the communication groove 16 includes a bottom surface 16c, an outer side surface 16d and an inner side surface 16e that stand upright from the bottom surface 16c. The outer side surface 16d and the inner side surface 16e are parallel to each other and perpendicular to the flat end surfaces formed by the lands 12a, 12b, and 12c, respectively. The communication groove 16 has a curved shape that is convex toward the inner diameter side in the axial direction view and is not connected to the atmosphere A side of the stationary seal ring 10. That is, an annular land 12c is formed on the inner diameter side of the communication groove 16 and the shallow groove 9.

[0030] Also, the radial width dimension L40 of the communication groove 16 is formed to be narrower than the radial width dimension L50 of the shallow groove 9 (L40 < L50).

[0031] The maximum width dimension L60 of the land 12b in the radial direction is smaller than the radial width dimension L40 of the communication groove 16 (L60 < L40). In addition, the radial width dimension L40 of the communication groove 16 is smaller than the circumferential width dimension L70 of the fluid guiding groove 15 (L40 < L70). Furthermore, the circumferential width dimension L70 of the fluid guiding groove 15 is smaller than the radial width dimension L50 of the shallow groove 9 (L70 < L50).

[0032] Also, the radial width dimension L60 of the land 12b is smaller than the minimum width dimension L90 in the radial direction of the land 12c (L60 < L90).

[0033] The circumferential width dimension L80 of the land 12b is larger than the circumferential width dimension L70 of the fluid guiding groove 15 (L70 < L80). Also, the circumferential width dimension L80 of the land 12b is slightly smaller than the radial width dimension L50 of the shallow groove 9 (L80 < L50). Note that the circumferential width dimension L80 of the land 12b may be greater than or equal to the radial width dimension L50 of the shallow groove 9, and preferably, it is within 10 times the width dimension L70.

[0034] Also, the communication groove 16 has a symmetrical shape with respect to the line LN extending in the radial direction along the fluid guiding groove 15. Further, the vicinity of the start end portion 9a of the shallow groove 9 and the vicinity of the end end portion 9b of the shallow groove 9 also have a symmetrical shape with respect to the line LN.

[0035] As shown in FIGS. 3(a) and (b), the depth dimension L10 of the fluid guiding groove 15 is deeper than the depth dimension L20 of the shallow groove 9 and the depth dimension L30 of the communication groove 16 (L10 > L20, L30). Also, as shown in FIG. 3(c), the depth dimension L30 of the communication groove 16 is the same as the depth dimension L20 of the shallow groove 9 (L20 = L30).

[0036] Specifically, in the first embodiment, the depth dimension L10 of the fluid guiding groove 15 is formed to be 100 μm, and the depth dimensions L20 of the shallow groove 9 and L30 of the communication groove 16 are formed to be 1 μm. Note that if the depth dimension of the fluid guiding groove 15 is formed deeper than the depth dimensions of the shallow groove 9 and the communication groove 16, the depth dimensions of the fluid guiding groove 15, the shallow groove 9, and the communication groove 16 can be freely changed. Preferably, the dimension L10 is 5 times or more the dimensions L20 and L30.

[0037] That is, the volume of the fluid guiding groove 15 is larger than the volume of the shallow groove 9, and the volume of the shallow groove 9 is larger than the volume of the communication groove 16.

[0038] Next, the operation of the stationary seal ring 10 and the rotary seal ring 20 during relative rotation will be described with reference to Figure 4. First, when the rotary seal ring 20 is not rotating and the general industrial machine is not in operation, the sealed fluid F flows into the shallow groove 9 and the communicating groove 16 via the fluid guide groove 15. Furthermore, since the stationary seal ring 10 is urged toward the rotary seal ring 20 by the bellows 7, almost no fluid leaks out between the sliding surfaces 11, 21 to the low-pressure side.

[0039] When the rotating seal ring 20 rotates relative to the stationary seal ring 10, the sealed fluid F on the outer diameter side of the sliding surfaces 11, 21 is drawn between the sliding surfaces 11, 21, and the sliding surfaces 11, 21 are slightly separated from each other by the positive pressure generated by the positive pressure generating mechanism (not shown) described above.

[0040] 4, the sealed fluid F that has flowed into the shallow groove 9 moves in the rotational direction of the rotary seal ring 20 due to friction with the sliding surface 21 as shown by arrow L1. The sealed fluid F that has moved along the shallow groove 9 flows out into the fluid guide groove 15 at the terminal end 9b of the shallow groove 9 as shown by arrow L2.

[0041] Similarly, the sealed fluid F that has flowed into the communicating groove 16 moves in the rotational direction of the rotary seal ring 20 due to friction with the sliding surface 21 as shown by arrow L4.

[0042] As described above, the communication port between the start end 9a of the shallow groove 9 and the fluid guide groove 15 is narrowed, so when the relative rotational speed between the stationary seal ring 10 and the rotating seal ring 20 exceeds a certain level, the flow rate of the sealed fluid F that moves within the shallow groove 9 and the communicating groove 16 and flows out to the fluid guide groove 15 becomes greater than the flow rate of the sealed fluid F that is supplied from the fluid guide groove 15 to the shallow groove 9, and a negative pressure is generated throughout the shallow groove 9 and the communicating groove 16.

[0043] Furthermore, when the relative rotational speed between the stationary seal ring 10 and the rotating seal ring 20 exceeds a certain level, the sealed fluid F in the fluid guide groove 15 is pushed outwardly as shown by arrow L3 by the sealed fluid F flowing in from the terminal end 9b of the shallow groove 9. Furthermore, during relative rotation between the stationary seal ring 10 and the rotating seal ring 20, the sealed fluid F constantly flows in between the sliding surfaces 11, 21 from the outer diameter sides thereof and from within the fluid guide groove 15, providing excellent lubrication.

[0044] At this time, the sealed fluid F around the shallow groove 9 is sucked into the shallow groove 9 from the lands 12a and 12c as shown by arrow H1 due to the negative pressure generated in the shallow groove 9. Also, the sealed fluid F near the fluid guide groove 15 enters the fluid guide groove 15 as shown by arrow H3, and part of the sealed fluid F in the fluid guide groove 15 flows out between the sliding surfaces 11 and 21 due to friction with the sliding surface 21, etc. as shown by arrow H4.

[0045] Furthermore, the sealed fluid F leaking from the inner diameter side end 15A of the fluid guide groove 15 or the terminal end 9b of the shallow groove 9 to the land 12b on the inner diameter side is sucked into the communicating groove 16 as shown by arrow H5 by the negative pressure generated in the communicating groove 16, and flows out toward the starting end 9a of the shallow groove 9. Since negative pressure is generated in the communicating groove 16, the sealed fluid F in the land 12c near the communicating groove 16 can also be collected as shown by arrow H6.

[0046] As explained above, the communicating groove 16, which connects the start end 9a and the end end 9b of the shallow groove 9, is disposed on the inner diameter side of the inner diameter side end 15A of the fluid guide groove 15 so as to surround the inner diameter side end 15A of the fluid guide groove 15 in the circumferential direction. With this, the sealed fluid F that flows out from the inner diameter side end 15A of the fluid guide groove 15 toward the inner diameter side during relative rotation between the stationary seal ring 10 and the rotary seal ring 20 can be collected by the communicating groove 16, and leakage of the sealed fluid F to the atmosphere A side can be suppressed.

[0047] Furthermore, the communicating groove 16 is provided at a distance toward the inner diameter side from the inner diameter side end 15A of the fluid guide groove 15. This allows a portion of the sealed fluid F in the fluid guide groove 15 to flow from the inner diameter side end 15A to the inner diameter side land 12b. In other words, since a portion of the sealed fluid F in the fluid guide groove 15 does not directly flow into the communicating groove 16, the generation of positive pressure in the communicating groove 16 is suppressed, negative pressure is easily maintained, and the ability of the communicating groove 16 to recover the sealed fluid F can be maintained.

[0048] Furthermore, since the depth dimension L30 of the communicating groove 16 is formed to be the same as the depth dimension L20 of the shallow groove 9, negative pressure can be generated in the communicating groove 16 during relative rotation between the stationary seal ring 10 and the rotating seal ring 20, thereby increasing the ability of the communicating groove 16 to recover the sealed fluid F.

[0049] Furthermore, since no step is formed between the communicating groove 16 and the shallow groove 9, it is possible to prevent positive pressure from being generated between the communicating groove 16 and the shallow groove 9, and the recovery ability of the sealed fluid F by the communicating groove 16 can be maintained.

[0050] Furthermore, width dimension L40 of communicating groove 16 is formed narrower than width dimension L50 of shallow groove 9. This allows the volume of communicating groove 16 to be reduced, so that communicating groove 16 is less likely to affect the negative pressure generating function of shallow groove 9.

[0051] Furthermore, since the volume of the communicating groove 16 is smaller than the volume of the shallow groove 9, the pressure within the communicating groove 16 during relative rotation between the stationary seal ring 10 and the rotating seal ring 20 is lower than the pressure within the shallow groove 9, making it easier to collect the sealed fluid F that has leaked from the inner diameter side end 15A of the fluid guide groove 15 in the communicating groove 16.

[0052] Furthermore, since the communicating groove 16 has a curved shape that convexly faces the inner diameter side when viewed in the axial direction, the overall length of the communicating groove 16 can be shortened while maintaining the radial separation distance between the communicating groove 16 and the inner diameter side end 15A of the fluid guide groove 15.

[0053] Also, the radial width dimension L60 of the land 12b is smaller than the minimum width dimension L90 in the radial direction of the land 12c (L60 < L90). In other words, by keeping the radial width dimension L60 of the land 12b small, the radial width dimension L90 of the land 12c can be ensured to be large, so that the sealed fluid F is less likely to leak into the space on the atmosphere A side.

[0054] Also, since no corners are formed in the communication groove 16, the flow in the communication groove 16 becomes smooth, and the generation of positive pressure in the communication groove 16 can be suppressed.

[0055] Also, the shallow groove 9 extends concentrically over the entire circumference of the sliding surface 11 and communicates circumferentially at the start end 9a and the end end 9b with respect to one fluid guiding groove 15. Therefore, a negative pressure can be generated in the shallow groove 9 over the entire circumference of the sliding surface 11. Further, since the sealed fluid F at the end end 9b of the shallow groove 9 flows into the fluid guiding groove 15, the generation of positive pressure between the sliding surfaces 11 and 21 can be suppressed by the shallow groove 9.

[0056] Also, since the fluid guiding groove 15 communicates with the sealed fluid side on the outer diameter side, the sealed fluid F recovered from the shallow groove 9 and the communication groove 16 can be returned to the sealed fluid side on the outer diameter side. Further, when the stationary seal ring 10 and the rotary seal ring 20 rotate relative to each other, the sealed fluid F can be easily returned to the sealed fluid side on the outer diameter side by centrifugal force, and the leakage of the sealed fluid F to the low pressure side on the inner diameter side rather than the sliding surfaces 11 and 21 can be reduced.

[0057] Also, the start end 9a and the end end 9b of the shallow groove 9 have a symmetric shape with respect to a line LN extending radially along the fluid guiding groove 15. Therefore, regardless of the relative rotation direction between the stationary seal ring 10 and the rotary seal ring 20, a negative pressure can be generated in the same manner in the communication groove 16. Incidentally, when the relative rotation direction of the sliding parts is in one direction, a throttle may be formed at the start end in the relative rotation direction of the shallow groove.

Example

[0058] Next, the sliding parts according to Example 2 will be described with reference to FIG. 5. Incidentally, the description of the same configurations as those in the above Example 1 will be omitted.

[0059] 5, in the stationary seal ring 100 of the second embodiment, an end 90f on the start end 90a side and an end 90g on the terminal end 90b side of the inner surface 90e of the shallow groove 90 extend linearly so as to incline toward the inner diameter side as they move away from the inner diameter side end face 150a of the fluid guide groove 150 in the circumferential direction when viewed in the axial direction. That is, the groove widths of the start end 90a and the terminal end 90b of the shallow groove 90 narrow toward the fluid guide groove 150. Note that a portion 90h of the inner surface 90e other than the ends 90f, 90g extends in an arc shape.

[0060] The communication groove 160 circumferentially communicates between the portions of the shallow groove 90 at the start end 90a and the end end 90b that are located radially inward of the inner diameter side end face 150a of the fluid guide groove 150.

[0061] More specifically, the inner surface 160e of the communicating groove 160 is circumferentially flush with and continuous with a portion 90h of the inner surface 90e of the shallow groove 90. The outer surface 160d of the communicating groove 160 extends parallel to the inner surface 160e at a position spaced radially inward from the end surface 150a of the fluid guide groove 150. In other words, a land 120b is formed between the fluid guide groove 150 and the communicating groove 160.

[0062] In this way, the communication groove 160 and the fluid guide groove 150 are separated by the land 120b, so that the generation of positive pressure within the communication groove 160 is suppressed, and the recovery ability of the sealed fluid F by the communication groove 160 can be maintained.

[0063] Furthermore, since the communication groove 160 has a curved shape that is convex on the outer diameter side when viewed in the axial direction, the flow inside the communication groove 160 can be made smooth.

[0064] Furthermore, the portion 90h other than the ends 90f, 90g on the inner surface 90e of the shallow groove 90 and the inner surface 160e of the communicating groove 160 are arranged on the same circumference and are continuous in the circumferential direction, which allows for smooth flow of the sealed fluid F near the communication opening between the communicating groove 160 and the shallow groove 90. [Example]

[0065] Next, a sliding element according to a third embodiment will be described with reference to Fig. 6. Note that a description of the same configuration as in the first embodiment will be omitted.

[0066] As shown in FIG. 6, in the stationary seal ring 110 of the second embodiment, the shallow groove 91, the communication groove 161 and the fluid guide groove 15 are separated by the land 12a'.

[0067] The land 12a' is composed of a portion located on the outer diameter side of the shallow groove 91, a portion located between the starting end 91a of the shallow groove 91 and the fluid guide groove 15, a portion located between the ending end 91b of the shallow groove 91 and the fluid guide groove 15, and a portion located between the connecting groove 161 and the fluid guide groove 15.

[0068] Since the shallow groove 91 and the communicating groove 161 are separated from the fluid guide groove 15 by the land 12a', negative pressure is easily generated in the shallow groove 91 and the communicating groove 161, resulting in an excellent recovery capability of the sealed fluid F. Furthermore, negative pressure can be reliably generated in the shallow groove 91 and the communicating groove 161, not limited to the relative rotation direction of the sliding parts.

[0069] When the relative rotation direction of the sliding parts is unidirectional, it is sufficient to provide a land at one of the circumferential ends of the shallow groove.

[0070] In the first to third embodiments, an inside type seal ring that seals the sealed fluid F that tends to leak from the outer diameter side toward the inner diameter side of the sliding surface has been exemplified. However, the present invention is not limited to this, and an outside type seal ring that seals the sealed fluid F that tends to leak from the inner diameter side toward the outer diameter side of the sliding surface may also be used. Here, an example in which the same concept as in the first embodiment is applied to an outside type seal ring will be described with reference to FIG. 7. In this case, the stationary seal ring 120 has a fluid guide groove 151 that communicates with the space on the inner diameter side where the sealed fluid F is located, a shallow groove 93 that extends annularly in the circumferential direction from an outer diameter side end 151A of the fluid guide groove 151, a communicating groove 163 that is provided on the outer diameter side of the outer diameter side end 151A of the fluid guide groove 151, and a land 121b that is formed between the communicating groove 163 and the outer diameter side end 151A of the fluid guide groove 151. The shallow groove 93 and the communicating groove 163 are symmetrical with respect to a line LN that extends radially along the fluid guide groove 151.

[0071] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0072] For example, in the above-described Examples 1 to 3, the shallow grooves have the same depth except for the narrowed portions which are communicating ports with the deep grooves, but the shallow grooves may be provided with steps or inclined surfaces.

[0073] Furthermore, in the above-described first to third embodiments, the communicating grooves are formed to the same depth as the deepest portions of the shallow grooves, but they may be formed to a depth different from that of the shallow grooves.

[0074] Although the embodiments 1 to 3 illustrate the configuration in which negative pressure is generated in the communicating groove, the communicating groove may be formed to a depth that does not generate negative pressure. Even in this case, the communicating groove is located on the leakage side of the deep groove, so that the sealed fluid leaking from the deep groove can be recovered.

[0075] Furthermore, in the first to third embodiments, the communicating grooves have a curved shape when viewed in the axial direction, but this is not limiting, and they may have, for example, a U-shape when viewed in the axial direction or a linear shape when viewed in the axial direction.

[0076] Furthermore, in Examples 1 to 3, the shallow groove is shown to be annular, but this is not limited to this. For example, two independent shallow grooves may be arranged on both circumferential sides of one deep groove, and these may be connected by a connecting groove.

[0077] Furthermore, in Examples 1 to 3, a negative pressure generating mechanism consisting of one shallow groove, one deep groove, and one connecting groove is exemplified, but multiple shallow grooves, multiple deep grooves, and multiple connecting grooves may be provided.

[0078] In addition, in the above-described Examples 1 to 3, the deep groove is in communication with the sealed fluid side on the outer diameter side, but this is not limiting. For example, the deep groove may not be in communication with the atmosphere side or the sealed fluid side of the sliding member.

[0079] Furthermore, the size and shape of the deep groove may be freely changed as long as the sealed fluid flowing out from the end of the shallow groove can be recovered to the extent that no positive pressure is generated between the sliding surfaces or that the positive pressure can be suppressed.

[0080] Furthermore, the cross-sectional shape of the shallow groove may be freely changed as long as the starting and ending ends of the shallow groove gradually become shallower toward the deep groove. When the relative rotation direction of the sliding parts is only one direction, it is sufficient that at least the starting end of the shallow groove gradually becomes shallower toward the deep groove.

[0081] In addition, in the above-described Examples 1 to 3, the shallow grooves and the communicating grooves are exemplified as having a rectangular shape in a radial cross section, but the shapes of the shallow grooves and the communicating grooves may be freely changed, for example, the shallow grooves and the communicating grooves may be U-shaped in a radial cross section. In this case, since no corners are formed at the bottoms of the shallow grooves and the communicating grooves, the flow of the sealed fluid F can be made smooth. In this case, it is preferable to form the opening of the communicating portion between the shallow grooves and the communicating grooves large so that the communicating portion does not become shallow.

[0082] Furthermore, in the first to third embodiments, the sliding parts are explained using mechanical seals for general industrial machinery as examples, but other mechanical seals for automobiles, water pumps, etc. are also acceptable. Furthermore, the sliding parts are not limited to mechanical seals, and may be sliding bearings or other sliding parts other than mechanical seals.

[0083] In addition, in the above-described first to third embodiments, examples have been described in which the negative pressure generating mechanism is provided only in the stationary seal ring, but the negative pressure generating mechanism may be provided only in the rotary seal ring 20, or may be provided in both the stationary seal ring and the rotary seal ring.

[0084] In addition, although the sealed fluid side has been described as the high-pressure side and the leakage side as the low-pressure side, the sealed fluid side may be the low-pressure side and the leakage side may be the high-pressure side, or the sealed fluid side and the leakage side may be at approximately the same pressure. [Explanation of symbols]

[0085] 9 Shallow Groove 9a Starting end 9b Termination section 9c Bottom 9d External surface 9e Inside surface 10 Stationary seal ring (sliding part) 11 Sliding surface 12a~12c Land 14 Negative pressure generating mechanism 15 Fluid guide groove (deep groove) 16 Communication groove 16c bottom 16d External surface 16e Inside surface 20 Rotating seal ring (sliding part) 21 Sliding surface 90 Shallow Groove 90a Starting end 90b Termination 91 Shallow Groove 91a Starting end 91b Termination section 100,110 Stationary seal ring (sliding part) 120b rand 150 Fluid guide groove (deep groove) 160,161 Communication groove A. Atmosphere F Sealed fluid

Claims

1. An annular sliding component that is arranged at a relatively rotating portion of a rotary machine and slides relative to other sliding components, a sliding surface of the sliding element is provided with a shallow groove extending in a circumferential direction for generating a negative pressure, and a deep groove deeper than the shallow groove for recovering the sealed fluid in the shallow groove, The shallow grooves are disposed on both sides of the deep groove in the circumferential direction, A sliding component in which a communicating groove that communicates the shallow grooves on both sides in the circumferential direction is provided on the leakage side of the leakage side end of the deep groove.

2. The sliding element according to claim 1 , wherein the communicating groove is provided away from the leakage side end of the deep groove.

3. 2. The sliding element according to claim 1, wherein the communicating groove is formed to the same depth as the shallow groove.

4. The sliding element according to claim 1 , wherein the communicating groove is formed to be narrower than the shallow groove.

5. The sliding element according to claim 1 , wherein the communication groove has a curved shape that is convex toward the leakage side.

6. The sliding element according to claim 1 , wherein the communicating groove has a symmetrical shape with respect to a line that passes through the deep groove and extends in a radial direction.

7. 7. The sliding element according to claim 1, wherein the shallow groove extends over the entire circumference of the sliding surface of the sliding element and has a start end and an end end that are continuous with the deep groove in the circumferential direction.

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