Patent Description:
The performance of a sliding component is often evaluated in terms of the amount of leakage, the amount of wear, and torque. In the related art, low leakage, long life, and low torque are realized by friction being reduced by fluid interposition between sliding surfaces and liquid leakage from a sliding surface being prevented and, in a mechanical seal, by performance enhancement through sliding material or sliding surface roughness optimization. However, further mechanical seal performance improvement is required with the awareness of environmental issues in recent years growing. Existing mechanical seal-related inventions include one in which a dynamic pressure generation groove is provided in the sliding surface of a rotating ring as a sliding component (See, for example, Patent Citation <NUM>).

Patent Citation <NUM> discloses a sliding component according to the preamble of claim <NUM> in which a fluid is actively taken into sealing faces and discharged from the sealing faces so as to prevent concentration of sediment causative substances on the sealing faces and hence prevent generation of sediment while preventing leakage of the fluid taken into the sealing faces to a low pressure fluid side.

Similarly, in Patent Citation <NUM> it is described that a concentration of sediment causative substances on sealing faces is prevented and hence generation of sediment is prevented, so that a sealing function of the sealing faces is maintained for a long time. Fluid circulation grooves are provided in one of the sealing faces. A positive pressure generation mechanism is provided in a part surrounded by the fluid circulation groove and a high pressure fluid side, a negative pressure generation mechanism is provided on a low pressure fluid side between the plurality of fluid circulation grooves, an auxiliary fluid circulation groove is provided on the high pressure fluid side between the plurality of fluid circulation grooves and an auxiliary positive pressure generation mechanism is provided in a part surrounded by the auxiliary fluid circulation groove and the high pressure fluid side.

No leakage occurs when such a mechanical seal is stationary. During rotation, including the initial stage of rotation, such a mechanical seal operates by fluid lubrication and prevents leakage to achieve both sealing and lubrication while having low friction. A method for this friction reduction is achieved by a dynamic pressure generation groove being formed in a sliding surface, a positive pressure being generated by a fluid that has intruded into the dynamic pressure generation groove of the sliding surface as a result of rotation, and sliding being performed with a liquid film interposed between the sliding surfaces as a result. However, in this type of mechanical seal, foreign matter may intrude into the dynamic pressure generation groove together with the sealing target fluid on the high-pressure side and adhere and stay. This foreign matter may lead to an insufficient dynamic pressure on the sliding surface, damage to the sliding surface, and poor durability.

The present invention has been made in view of such problems, and an object of the present invention is to provide a sliding component capable of preventing foreign matter from staying in a dynamic pressure generation groove and realizing low leakage, long life, and low torque over a long period of time.

In order to solve the above problem, a sliding component according to the present invention is a sliding component including a plurality of dynamic pressure generation grooves formed in a sliding surface of the sliding component so as to be arranged in a circumferential direction and configured for generating a dynamic pressure on the sliding surface of the sliding component, wherein each of the dynamic pressure generation grooves includes: an introduction port which is formed in a first end side of the dynamic pressure generation groove in a circumferential direction and which is open to a sealing target fluid side; a throttle portion communicating with the introduction port and having a narrowed flow path; and a lead-out port which is formed on a second end side of the dynamic pressure generation groove opposed to the first end side in the circumferential direction, which communicates with the throttle portion and which is open to the sealing target fluid side, wherein the adjoining dynamic pressure generation grooves in the circumferential direction are in a non-communication state and an opening of the lead-out port which is opened to the sealing target fluid side is smaller, in area, than an opening of the introduction port which is opened to the sealing target fluid side. According to the aforesaid feature of the present invention, the lead-out port of the dynamic pressure generation groove communicates with the sealing target fluid side, and thus foreign matter that has intruded into the dynamic pressure generation groove from the introduction port can be discharged to the sealing target fluid side through the lead-out port and the foreign matter is prevented from staying in the dynamic pressure generation groove. As a result, it is possible to realize low leakage, long life, and low torque over a long period of time.

In an embodiment not belonging to the present invention the sliding component further includes at least another dynamic pressure generation groove, the dynamic pressure generation grooves are arranged in the circumferential direction in the sliding surface, and the lead-out port of one of adjoining two of the dynamic pressure generation grooves and the introduction port of remaining one of the adjoining two of the dynamic pressure generation grooves communicate with each other. According to this configuration, the adjoining two dynamic pressure generation grooves are capable of communicating with each other and the fluidity of the foreign matter contained in the sealing target fluid can be enhanced.

In another embodiment not belonging to the present invention the dynamic pressure generation grooves communicate in an annular shape over an entire circumference of the sliding surface. According to this configuration, foreign matter that has intruded into the annular dynamic pressure generation groove from the introduction port is discharged from any of the lead-out ports while annularly circulating in the dynamic pressure generation groove. Accordingly, the foreign matter is unlikely to stay in the dynamic pressure generation groove.

According to the present invention the sliding component further includes at least another dynamic pressure generation groove, the dynamic pressure generation grooves are arranged in the circumferential direction in the sliding surface, and adjoining two of the dynamic pressure generation grooves are separated from each other in the circumferential direction. According to this configuration, lubricity is enhanced by the plurality of dynamic pressure generation grooves. In addition, the part where the dynamic pressure generation grooves are separated from each other is capable of maintaining sealability.

It may be preferable that the introduction port is formed so as to be a deep groove deeper than the throttle portion. According to this preferable configuration, a large amount of sealing target fluid can be introduced toward the throttle portion from the introduction port formed in the deep groove.

It may be preferable that the lead-out port is formed so as to be a deep groove deeper than the throttle portion. According to this preferable configuration, the lead-out port formed by the deep groove achieves the effect of a pressure release groove and the sealing target fluid and the foreign matter contained in the sealing target fluid are led out with ease.

It may be preferable that the introduction port, the throttle portion, and the lead-out port are formed so as to be equal to each other in depth. According to this preferable configuration, foreign matter that has intruded from the introduction port can be smoothly discharged to the lead-out port.

It may be preferable that the dynamic pressure generation groove further includes at least another lead-out ports. According to this preferable configuration, foreign matter that has intruded from the introduction port can be easily discharged via the plurality of lead-out ports.

It may be preferable that the throttle portion is curved from an inner diameter side toward an outer diameter side of the sliding surface as the throttle portion extends to the lead-out port. According to this preferable configuration, the sealing target fluid and the foreign matter contained in the sealing target fluid are easily discharged from the lead-out port by centrifugal force during sliding.

Modes for implementing the sliding component according to the present invention will be described below based on embodiments.

The sliding component according to the first embodiment not belonging to the the present invention will be described with reference to <FIG>. It should be noted that the right side of the page of <FIG> is an atmospheric side and the left side of the page is an intra-machine side in the following description of the present embodiment.

As illustrated in <FIG>, a sliding component <NUM> according to the first embodiment of the present invention is a rotating seal ring <NUM> and a fixed seal ring <NUM> in a mechanical seal <NUM> and is provided between a rotary shaft <NUM> of a rotating machine such as a pump (not illustrated) and a compressor (not illustrated) and a seal cover <NUM> fixed to the housing of the rotating machine. The mechanical seal <NUM> includes a stationary side element having the circular ring-shaped fixed seal ring <NUM> fixed to the seal cover <NUM> and a rotating side element rotating together with the rotary shaft <NUM>. A sliding surface S1 of the fixed seal ring <NUM> and a sliding surface S2 of the rotating seal ring <NUM> are slid closely with each other, the sealing target fluid on the intra-machine high-pressure fluid side (hereinafter, referred to as the high-pressure fluid H side) is shaft-sealed, and leakage to the atmosphere A side is prevented. It should be noted that the mechanical seal <NUM> is configured as a balanced mechanical seal in which the balance of the pressure of the sealing target fluid acting on the fixed seal ring <NUM> and the rotating seal ring <NUM> is constant on both sides in the axial direction.

The fixed seal ring <NUM> and the rotating seal ring <NUM> are typically formed of a combination of SiC (as an example of hard material) or a combination of SiC (as the example of hard material) and carbon (as an example of soft material). However, the present invention is not limited thereto and any sliding material can be applied insofar as it is used as a sliding material for a mechanical seal. It should be noted that the SiC includes a sintered body using boron, aluminum, carbon, or the like as a sintering aid and a material made of two or more types of phases having different components and compositions, examples of which include SiC in which graphite particles are dispersed, reaction-sintered SiC made of SiC and Si, SiC-TiC, and SiC-TiN. As the carbon, resin-molded carbon, sintered carbon, and the like can be used, including carbon in which carbon and graphite are mixed. In addition to the above sliding materials, a metal material, a resin material, a surface modification material (e.g., coating material), a composite material, and the like can also be applied.

As illustrated in <FIG>, the fixed seal ring <NUM> is formed in an annular shape so as to surround the rotary shaft <NUM> and a dynamic pressure generation groove <NUM> is formed on the sliding surface S1 by surface texturing or the like. It should be noted that the rotating seal ring <NUM> disposed so as to face the sliding surface S1 of the fixed seal ring <NUM> is provided so as to rotate clockwise (i.e., in the illustrated arrow direction) with respect to the fixed seal ring <NUM>.

The sliding surface S1 of the fixed seal ring <NUM> includes a plurality of the dynamic pressure generation grooves <NUM> arranged along the circumferential direction and a flat seal surface M1 formed on the inner diameter side as compared with the dynamic pressure generation grooves <NUM>. Each dynamic pressure generation groove <NUM> mainly includes a communication port 40a as an introduction port opening at the outer diameter end and communicating with the fluid H side, a communication groove 46a extending in the inner diameter direction from the communication port 40a, a flow path portion <NUM> communicating with the communication groove 46a and extending in the circumferential direction of the fixed seal ring <NUM>, a communication groove 46b communicating with the flow path portion <NUM> and extending in the outer diameter direction, and a communication port 40b as a lead-out port opening at the outer diameter end of the communication groove 46b and communicating with the fluid H side. In addition, the sliding surface S1 includes a seal surface L on the outer diameter side surrounded by the communication groove 46a, the flow path portion <NUM>, and the communication groove 46b and is formed at the same height as the seal surface M1.

The flow path portion <NUM> includes a throttle portion <NUM>, which gradually decreases in width from the communication groove 46a side toward the communication groove 46b side along the circumferential direction. Specifically, the flow path portion <NUM> includes an outer wall portion <NUM> on the outer diameter side of the fixed seal ring <NUM>, an inner wall portion <NUM> on the inner diameter side of the fixed seal ring <NUM>, and a flat bottom surface portion <NUM> parallel to the seal surface M1 and the narrow throttle portion <NUM> is formed by the inner wall portion <NUM> gradually approaching the outer diameter side along the circumferential direction with respect to the outer wall portion <NUM> extending in the circumferential direction in a circular arc shape concentric with the fixed seal ring <NUM>. The bottom surface portion <NUM> of the flow path portion <NUM> is formed on a flat surface having a constant depth shallower than the bottom surface of the communication groove 46a up to the throttle portion <NUM>. In addition, the communication groove 46a is a groove deeper than the bottom surface portion <NUM> of the flow path portion <NUM> and a step portion 47a is formed at the boundary between the communication groove 46a and the bottom surface portion <NUM> of the flow path portion <NUM>. Further, the communication groove 46b is a groove deeper than the bottom surface portion <NUM> of the flow path portion <NUM> and a step portion 47b is formed at the boundary between the communication groove 46b and the bottom surface portion <NUM> of the flow path portion <NUM>.

As illustrated in <FIG>, the throttle portion <NUM> causes a radial width N1 near the inlet of the flow path portion <NUM> to exceed a radial width N2 near the outlet of the flow path portion <NUM>. As a result, during sliding with the rotating seal ring <NUM>, the pressure of the sealing target fluid that has flowed in from the communication port 40a communicating with the high-pressure fluid H side is gradually increased by the throttle portion <NUM> and positive pressure generation occurs between the sliding surface S1 of the fixed seal ring <NUM> and the sliding surface S2 of the rotating seal ring <NUM>.

In addition, the plurality of dynamic pressure generation grooves <NUM> arranged along the circumferential direction in the sliding surface S1 have the same configuration and shape without exception and the communication port 40a as an introduction port in the dynamic pressure generation groove <NUM> is configured as the lead-out port of the dynamic pressure generation groove <NUM> adjacent to the upstream side of the dynamic pressure generation groove <NUM>. In addition, the communication port 40b as a lead-out port in the dynamic pressure generation groove <NUM> is configured as the introduction port of the dynamic pressure generation groove <NUM> adjacent to the downstream side of the dynamic pressure generation groove <NUM>.

In this manner, the introduction ports and the lead-out ports of the adjacent dynamic pressure generation grooves <NUM> are sequentially arranged in a communicating state, and thus the plurality of dynamic pressure generation grooves <NUM> communicate in an annular shape over the entire circumference of the sliding surface S1.

Although the dynamic pressure generation groove <NUM> forms a liquid film between the sliding surface S1 and the sliding surface S2 and improve lubricity by the throttle portion <NUM> generating the positive pressure, the seal surface M1 is flat, and thus the liquidtightness of the sliding surface S1 is retained even in the event of positive pressure generation by the dynamic pressure generation groove <NUM>.

As illustrated in <FIG> and <FIG>, the sealing target fluid that has flowed into the communication port 40a as a result of the sliding of the sliding surface S1 and the sliding surface S2 flows into the flow path portion <NUM> from the communication groove 46a, which is a groove deeper than the bottom surface portion <NUM> of the flow path portion <NUM>, over the step portion 47a. Although the positive pressure is gradually increased by the throttle portion <NUM> in the flow path portion <NUM>, the step portion 47b is formed such that the positive pressure-increased sealing target fluid is led out to the communication groove 46b, and thus the pressure of the sealing target fluid that has moved to the communication groove 46b is released and the sealing target fluid is discharged to the high-pressure fluid H side from the communication port 40b. In addition, since the inner wall portion <NUM> of the flow path portion <NUM> forms the throttle portion <NUM>, which has a flow path cross section gradually narrowing so as to become close toward the outer wall portion <NUM>, the discharge from the communication port 40b is facilitated by centrifugal force.

In the communication groove 46b at this time, convection occurs between the flow of the sealing target fluid to flow out to the fluid H side (i.e., intra-machine side) after passage through the flow path portion <NUM> of the dynamic pressure generation groove <NUM> and positive pressure release and the sealing target fluid to flow into the communication groove 46b from the fluid H side (i.e., intra-machine side) as the introduction port of the dynamic pressure generation groove <NUM> adjacent to the downstream side and fluidity enhancement occurs as a result. Accordingly, the communication groove 46b causes the foreign matter contained in the sealing target fluid to actively flow and be easily led out to the high-pressure fluid H side. In addition, not only the communication groove 46b but also the communication grooves 46a to <NUM> constituting the plurality of dynamic pressure generation grooves <NUM> arranged in the circumferential direction have the same effect. In other words, the communication groove 46b discharging the sealing target fluid in the dynamic pressure generation groove <NUM> also serves as an introduction port for the fluid H in the dynamic pressure generation groove <NUM> adjacent thereto. Accordingly, the dynamic pressure generation groove <NUM> can be formed in an annular shape over the entire circumference in the sliding surface S1 of the fixed seal ring <NUM>.

In addition, as illustrated in <FIG> and <FIG>, the fixed seal ring <NUM> in the first embodiment has the plurality of dynamic pressure generation grooves <NUM> arranged in the circumferential direction and mutually communicating in an annular shape over the entire circumference. Accordingly, even in the event of foreign matter intrusion from the communication port 40a, it circulates in the annular dynamic pressure generation groove <NUM>, and thus it flows without staying in the dynamic pressure generation groove and is eventually discharged to the high-pressure fluid H side from any of the communication ports 40a to <NUM>.

Since the lead-out port of the dynamic pressure generation groove <NUM> communicates with the high-pressure fluid H side in this manner, foreign matter that has intruded into the dynamic pressure generation groove <NUM> from the introduction port can be discharged to the high-pressure fluid H side through the lead-out port and the foreign matter is prevented from staying or accumulating in the dynamic pressure generation groove <NUM>. As a result, it is possible to realize low leakage, long life, and low torque over a long period of time.

In addition, in the throttle portion <NUM> in the present embodiment, the inner wall portion <NUM> is curved from the inner diameter side to the outer diameter side so as to gradually approach the outer wall portion <NUM> on the outer diameter side toward the communication port 40b along the circumferential direction. Accordingly, centrifugal force acts on the sealing target fluid and the foreign matter contained in the sealing target fluid and discharge to the high-pressure fluid H side on the outer diameter side is facilitated.

In addition, the plurality of dynamic pressure generation grooves <NUM> are arranged in the circumferential direction of the sliding surface S1 and the communication port 40b as the lead-out port of one adjacent dynamic pressure generation groove <NUM> and the communication port 40b as the introduction port of another dynamic pressure generation groove <NUM> are the same. Accordingly, the two dynamic pressure generation grooves <NUM> are capable of communicating with each other and the fluidity of the foreign matter contained in the sealing target fluid can be enhanced. It should be noted that the lead-out port of one adjacent dynamic pressure generation groove <NUM> and the introduction port of the other dynamic pressure generation groove <NUM> may be arranged side by side in a communicating state.

In addition, since the plurality of dynamic pressure generation grooves <NUM> are annularly arranged over the entire circumference of the sliding surface S1, foreign matter that has intruded into the annular dynamic pressure generation groove <NUM> from the communication port as an introduction port is discharged from any of the communication ports as a lead-out port while annularly circulating in the dynamic pressure generation groove <NUM>. Accordingly, the foreign matter is unlikely to stay in the dynamic pressure generation groove <NUM>.

In addition, the communication port 40a as an introduction port is formed in the groove in the throttle portion <NUM> of the flow path portion <NUM> deeper than the bottom surface portion <NUM>, and thus a large amount of fluid can be introduced toward the throttle portion <NUM> from the communication port 40a formed in the deep groove.

In addition, the communication port 40b as a lead-out port is formed in the groove in the throttle portion <NUM> of the flow path portion <NUM> deeper than the bottom surface portion <NUM>, and thus the communication port 40b formed in the deep groove achieves the effect of a pressure release groove and the sealing target fluid and the foreign matter contained in the fluid are led out with ease.

Next, the sliding component according to the second embodiment not belonging to the present invention will be described with reference to <FIG> and <FIG>. It should be noted that components identical to those of the first embodiment will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with a communication port 140a as an introduction port is formed such that each of an outer wall portion <NUM> and an inner wall portion <NUM> is formed concentrically with the fixed seal ring <NUM> and in a circular arc shape and is separate at equal intervals in the radial direction. In addition, a bottom surface portion <NUM> of the second embodiment is inclined at a constant angle from the lower surface to the upper surface from the upstream side toward the downstream side. Formed as a result is a throttle portion <NUM> that has a flow path cross section gradually narrowing in the circumferential direction over the entire flow path portion <NUM>.

<FIG> is a side cross-sectional view of the flow path portion <NUM>, in which a depth T2 from the sliding surface S1 on the communication groove 146b side as a lead-out port to the bottom surface of the bottom surface portion <NUM> is shallower than a depth T1 from the sliding surface S1 on the communication groove 146a side as an introduction port to the bottom surface of the bottom surface portion <NUM>. In other words, the flow path cross-sectional area of the flow path portion <NUM> gradually decreases from the depth T1 toward the depth T2. As a result, the positive pressure of the sealing target fluid that has flowed in from the communication groove 146a during sliding increases as the sealing target fluid moves over a step portion 147a to the communication groove 146b side as the downstream side of the flow path portion <NUM>. Subsequently, it is discharged to the high-pressure fluid H side from a communication port 140b of the communication groove 146b over a step portion 147b.

The effect of positive pressure generation can be enhanced since the throttle portion <NUM> is formed over the entire flow path portion <NUM> as described above. In addition, the throttle portion <NUM> is formed by the bottom surface portion <NUM> inclined at a constant angle, and thus a uniform and stable positive pressure generation effect can be obtained.

Next, the sliding component according to the third embodiment of the present invention will be described with reference to <FIG>. It should be noted that components identical to those of the first and second embodiments will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with a communication port 240a as an introduction port is formed by an outer wall portion <NUM> and an inner wall portion <NUM> being curved from the inner diameter side toward the outer diameter side of the fixed seal ring <NUM> along the circumferential direction. In addition, a communication port 240b as a lead-out port is open at the downstream outer diameter end of the flow path portion <NUM>. The outer wall portion <NUM> and the inner wall portion <NUM> are formed as a throttle portion <NUM> by gradually approaching each other toward the communication port 240b along the circumferential direction.

In addition, a bottom surface portion <NUM> of the flow path portion <NUM> is formed on a flat surface having a constant depth shallower than the bottom surface of the communication groove 46a up to the throttle portion <NUM> and the communication port 240b.

In addition, a plurality of the dynamic pressure generation grooves <NUM> of the third embodiment are arranged along the circumferential direction in the sliding surface S1 of the fixed seal ring <NUM>, the introduction ports and the lead-out ports of the adjacent dynamic pressure generation grooves <NUM> are separated from each other in the circumferential direction, and the part is formed as a seal surface M2.

The sealing target fluid that has flowed in from the communication port 240a illustrated in <FIG> flows into the flow path portion <NUM> over a step portion 247a. The positive pressure of the sealing target fluid that has flowed into the flow path portion <NUM> is increased by the throttle portion <NUM> formed by the outer wall portion <NUM> and the inner wall portion <NUM>. Subsequently, it is discharged from the communication port 240b to the high-pressure fluid H side.

The adjacent dynamic pressure generation grooves <NUM> of the present embodiment are separated from each other in the circumferential direction, and thus lubricity is enhanced by the plurality of dynamic pressure generation grooves <NUM>. In addition, the part where the dynamic pressure generation grooves <NUM> are separated from each other is capable of maintaining sealability as the seal surface M2.

In addition, in the throttle portion <NUM> in the present embodiment, the outer wall portion <NUM> and the inner wall portion <NUM> are curved from the inner diameter side toward the outer diameter side toward the communication port 240b along the circumferential direction, and thus centrifugal force acts on the sealing target fluid and the foreign matter contained in the sealing target fluid and the fluid is easily discharged to the high-pressure fluid H side on the outer diameter side. In addition, in the throttle portion <NUM>, each of the outer wall portion <NUM> and the inner wall portion <NUM> forms the throttle portion <NUM> by being convexly curved from the outer diameter side toward the inner diameter side of the sliding surface, and thus centrifugal force acts with ease.

Next, the sliding component according to the fourth embodiment of the present invention will be described with reference to <FIG>. It should be noted that components identical to those of the first to third embodiments will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with a communication port 340a as an introduction port has an outer wall portion <NUM> and an inner wall portion <NUM> circumferentially extending in a circular arc shape concentric with the fixed seal ring <NUM> along the circumferential direction. In addition, the downstream side of the flow path portion <NUM> is bent toward a communication port 340b as a lead-out port open at the outer diameter end, extends in the outer diameter direction, and is formed as a throttle portion <NUM> narrow in the circumferential direction. In other words, the circumferential width of the throttle portion <NUM> and the communication port 340b is narrower than that of a communication groove 346a provided with the communication port 340a. In addition, a bottom surface portion <NUM> of the flow path portion <NUM> is formed on a flat surface having a constant depth shallower than the bottom surface of the communication groove 346a up to the throttle portion <NUM> and the communication port 340b.

In addition, a plurality of the dynamic pressure generation grooves <NUM> of the fourth embodiment are arranged along the circumferential direction in the sliding surface S1 of the fixed seal ring <NUM>, the introduction ports and the lead-out ports of the adjacent dynamic pressure generation grooves <NUM> are separated from each other in the circumferential direction, and the part is formed as the seal surface M2.

The sealing target fluid that has flowed in from the communication port 340a illustrated in <FIG> flows into the flow path portion <NUM> over a step portion 347a. The positive pressure of the sealing target fluid that has flowed into the flow path portion <NUM> is increased by the narrow throttle portion <NUM> bent in the radial direction from the flow path portion <NUM>. Subsequently, it is discharged from the communication port 340b to the high-pressure fluid H side.

Next, the sliding component according to the fifth embodiment of the present invention will be described with reference to <FIG>. It should be noted that components identical to those of the first to fourth embodiments will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with a communication port 440a as an introduction port has an outer wall portion <NUM> and an inner wall portion <NUM> curved from the inner diameter side toward the outer diameter side of the fixed seal ring <NUM> along the circumferential direction. A communication port 440b as a lead-out port is open at the downstream outer diameter end of the flow path portion <NUM>. The outer wall portion <NUM> and the inner wall portion <NUM> are formed as a throttle portion <NUM> by gradually approaching each other toward the communication port 440b along the circumferential direction. The communication port 440a as the introduction port of the dynamic pressure generation groove <NUM> is considerably wider in the circumferential direction than the communication port 440b as a lead-out port.

In addition, a bottom surface portion <NUM> of the flow path portion <NUM> is formed on a flat surface having a constant depth up to the communication port 440a, the throttle portion <NUM>, and the communication port 440b.

In addition, a plurality of the dynamic pressure generation grooves <NUM> of the fifth embodiment are arranged along the circumferential direction in the sliding surface S1 of the fixed seal ring <NUM>, the introduction ports and the lead-out ports of the adjacent dynamic pressure generation grooves <NUM> are separated from each other in the circumferential direction, and the part is formed as the seal surface M2.

The positive pressure of the sealing target fluid that has flowed into the flow path portion <NUM> from the communication port 440a illustrated in <FIG> is increased by the throttle portion <NUM> formed by the outer wall portion <NUM> and the inner wall portion <NUM>. Subsequently, it is discharged from the communication port 440b to the high-pressure fluid H side.

In addition, in the throttle portion <NUM> in the present embodiment, the outer wall portion <NUM> and the inner wall portion <NUM> are curved from the inner diameter side toward the outer diameter side toward the communication port 440b along the circumferential direction, and thus centrifugal force acts on the sealing target fluid and the foreign matter contained in the sealing target fluid and the fluid is easily discharged to the high-pressure fluid H side on the outer diameter side. In addition, in the throttle portion <NUM>, each of the outer wall portion <NUM> and the inner wall portion <NUM> forms the throttle portion <NUM> by being convexly curved from the outer diameter side toward the inner diameter side of the sliding surface, and thus centrifugal force acts with ease.

Next, the sliding component according to the sixth embodiment not belonging to the present invention will be described with reference to <FIG>. It should be noted that components identical to those of the first to fifth embodiments will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with a communication port 540a as an introduction port includes a throttle portion <NUM> gradually decreasing in width from the communication groove 546a side toward the communication groove 546b side along the circumferential direction and communicates with a communication port 540b as a lead-out port. The narrow throttle portion <NUM> is formed by an inner wall portion <NUM> gradually approaching the outer diameter side along the circumferential direction with respect to an outer wall portion <NUM> circumferentially extending in a circular arc shape concentric with the fixed seal ring <NUM>.

In addition, the communication port 540a as an introduction port in the dynamic pressure generation groove <NUM> is configured as the lead-out port of the dynamic pressure generation groove <NUM> adjacent to the upstream side of the dynamic pressure generation groove <NUM>. In addition, the communication port 540b as a lead-out port in the dynamic pressure generation groove <NUM> is configured as the introduction port of the dynamic pressure generation groove <NUM> adjacent to the downstream side of the dynamic pressure generation groove <NUM>.

Further, all the inner diameter ends of the plurality of communication grooves 546a, 546b, and so on arranged in the circumferential direction are continuously formed in an annular shape by an annular groove <NUM> having the same depth as the communication grooves.

In addition, a communication port 540c extends to the inner diameter side beyond the annular groove <NUM> and communicates with a negative pressure generation groove <NUM> shallower than the communication port 540c. The negative pressure generation groove <NUM> extends in the circumferential direction from the communication port 540c toward the upstream side, and a circumferential end surface 55a is formed as a step portion in relation to the sliding surface S1 on the front side of the lap.

In this manner, a plurality of the dynamic pressure generation grooves <NUM> are annularly arranged over the entire circumference of the sliding surface S1, and thus foreign matter that has intruded into the annular dynamic pressure generation groove <NUM> from the communication ports 540a and 540b and so on as introduction ports is discharged from any of the communication ports 540b and 540c and so on as a lead-out port while annularly circulating in the dynamic pressure generation groove <NUM>. Accordingly, the foreign matter is unlikely to stay in the dynamic pressure generation groove <NUM>.

In addition, since the annular groove <NUM> communicating with all the circumferentially arranged communication grooves is formed, the sealing target fluid on the fluid H side can be introduced and led out to the fluid H side with ease and the fluidity of the foreign matter contained in the sealing target fluid can be enhanced.

The dynamic pressure generation groove <NUM> generates a positive pressure on the outer diameter side of the sliding surface S1 by means of the throttle portion <NUM>, slightly widens the gap with the sliding surface S2, and forms a liquid film between the sliding surfaces to improve lubricity. In addition, the negative pressure generation groove <NUM> narrows the gap with the sliding surface S2 by generating a negative pressure on the inner diameter side of the sliding surface S1 to enhance the liquidtightness between the sliding surfaces.

In addition, in the throttle portion <NUM> in the present embodiment, the inner wall portion <NUM> is curved from the inner diameter side to the outer diameter side so as to gradually approach the outer wall portion <NUM> toward the communication port 540b along the circumferential direction. Accordingly, centrifugal force acts on the sealing target fluid and the foreign matter contained in the sealing target fluid and the fluid is easily discharged to the high-pressure fluid H side on the outer diameter side.

Next, the sliding component according to the seventh embodiment not belonging to the present invention will be described with reference to <FIG>. It should be noted that components identical to those of the first to sixth embodiments will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with a communication port 640a as an introduction port includes a throttle portion <NUM> gradually decreasing in width from the communication groove 646a side toward the communication groove 646b side along the circumferential direction and communicates with a communication port 640b as a lead-out port. The narrow throttle portion <NUM> is formed by an outer wall portion <NUM> gradually approaching the inner diameter side along the circumferential direction with respect to an inner wall portion <NUM> circumferentially extending in a circular arc shape concentric with the fixed seal ring <NUM>.

In addition, the flow path portion <NUM> includes a communication port <NUM> as another lead-out port branching to the outer diameter side upstream of the throttle portion <NUM> and opening at the outer diameter end. The communication port <NUM> is smaller in cross-sectional area than the flow path portion <NUM> extending in the circumferential direction. More preferably, the communication port <NUM> is smaller in cross-sectional area than the throttle portion <NUM>.

As described above, the dynamic pressure generation groove <NUM> has the communication port 640b and the communication port <NUM> as lead-out ports. Accordingly, foreign matter that has intruded from the introduction port can be easily discharged via the plurality of communication ports 640b and <NUM>.

Next, the sliding component according to the eighth embodiment not belonging to the present invention will be described with reference to <FIG>. It should be noted that components identical to those of the first to seventh embodiments will be denoted by the same reference numerals with redundant description omitted.

As illustrated in <FIG>, in a dynamic pressure generation groove <NUM> formed in the sliding surface S1 of the fixed seal ring <NUM>, a flow path portion <NUM> communicating with the communication port 640a as an introduction port includes the throttle portion <NUM> gradually decreasing in width from the communication groove 646a side toward the communication groove 646b side along the circumferential direction and communicates with the communication port 640b as a lead-out port.

In addition, the flow path portion <NUM> includes a plurality of communication ports <NUM> as separate lead-out ports branching to the outer diameter side at a plurality of circumferential points upstream of the throttle portion <NUM> and opening at the outer diameter end. The communication port <NUM> is smaller in cross-sectional area than the flow path portion <NUM> extending in the circumferential direction. More preferably, the communication port <NUM> is smaller in cross-sectional area than the throttle portion <NUM>.

As described above, the dynamic pressure generation groove <NUM> has the communication port 640b and the plurality of communication ports <NUM> as lead-out ports. Accordingly, foreign matter that has intruded from the introduction port can be easily discharged via the plurality of communication ports 640b and <NUM>.

Although embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to the embodiments.

For example, although the dynamic pressure generation grooves of the embodiments are provided in the sliding surface S1 of the fixed seal ring <NUM>, the present invention is not limited thereto. For example, the dynamic pressure generation groove may be provided in the sliding surface S2 of the rotating seal ring <NUM>.

In addition, although a case where the outer diameter side of the seal ring is the high-pressure fluid H has been described above, the inner diameter side of the seal ring may be the fluid H as the sealing target fluid. In this case, the sliding component <NUM> is configured to be provided with the dynamic pressure generation groove <NUM> where the communication ports 40a to <NUM> communicate with the fluid H on the inner diameter side.

In addition, although a case where the sealing target fluid that is introduced into the dynamic pressure generation groove and led out is the fluid H on the high-pressure side has been described in the embodiments, the present invention is not limited thereto and the sealing target fluid may be a fluid on the low-pressure side.

Claim 1:
A sliding component (<NUM>) comprising a plurality of dynamic pressure generation grooves (<NUM>, <NUM>, <NUM>) formed in a sliding surface of the sliding component (<NUM>) so as to be arranged in a circumferential direction and configured for generating a dynamic pressure on the sliding surface of the sliding component (<NUM>),
wherein each of the dynamic pressure generation grooves (<NUM>, <NUM>, <NUM>) includes:
an introduction port (240a, 340a, 440a) which is formed in a first end side of the dynamic pressure generation grooves (<NUM>, <NUM>, <NUM>) in a circumferential direction and which is open to a sealing target fluid side;
a throttle portion (<NUM>) communicating with the introduction port (240a, 340a, 440a) and having a narrowed flow path; and
a lead-out port (240b, 340b, 440b) which is formed on a second end side of the dynamic pressure generation grooves (<NUM>, <NUM>, <NUM>) opposed to the first end side in the circumferential direction, which communicates with the throttle portion (<NUM>) and which is open to the sealing target fluid side, characterized in that
the adjoining dynamic pressure generation grooves (<NUM>, <NUM>, <NUM>) are isolated from each other by a seal surface in the circumferential direction such that the adjoining dynamic pressure generation grooves are in a non-communication state,
the lead-out port (240b, 340b, 440b) which is opened to the sealing target fluid side is smaller than the introduction port (240a, 340a, 440a) which is opened to the sealing target fluid side.