JP7846066B2 - Sliding parts - Google Patents

Description

This invention relates to sliding components, such as sliding components used in shaft seals and bearings.

In rotating machinery, mechanical seals are known as sliding components that prevent leakage of sealed fluids around the rotating shaft. These seals consist of a pair of annular sliding rings that rotate relative to each other, with their sliding surfaces sliding against each other. In recent years, for environmental reasons, there has been a desire to reduce the energy lost due to sliding in such mechanical seals, and some mechanical seals are equipped with dynamic pressure generating grooves on the sliding surfaces of the sliding rings.

For example, in the mechanical seal shown in Patent Document 1, the sliding surface of one sliding ring has a first negative pressure generating groove and a dynamic pressure generating groove on its inner diameter side, and a second negative pressure generating groove on its outer diameter side. The first negative pressure generating groove is partitioned by an annular land so as not to communicate with the second fluid space on the outer diameter side, and the second negative pressure generating groove is partitioned by an annular land so as not to communicate with the first fluid space on the inner diameter side. The dynamic pressure generating groove is located on the inner diameter side of the first negative pressure generating groove. Furthermore, one circumferential groove is formed between the first negative pressure generating groove and the second negative pressure generating groove, and another circumferential groove is formed between the first negative pressure generating groove and the dynamic pressure generating groove.

During relative forward rotation of the pair of sliding rings, dynamic pressure is generated at the closed end of the dynamic pressure generating groove by the first fluid on the inner diameter side. This causes a slight separation between the sliding surfaces, improving lubrication between them. Furthermore, the first fluid that flows out from the closed end of the dynamic pressure generating groove between the sliding surfaces is drawn in by the first negative pressure generating groove and discharged into other circumferential grooves. Additionally, the second fluid that flows from the second fluid space on the outer diameter side between the sliding surfaces due to the separation is drawn in by the second negative pressure generating groove and returned to the second fluid space. This ensures lubrication between the sliding surfaces while preventing the first fluid from flowing into the second fluid space, or vice versa.

International Publication No. 2018/092742 (page 11, Figure 3)

In the mechanical seal described in Patent Document 1, while mixing of the first and second fluids is suppressed by collecting the first fluid in one circumferential groove and the second fluid in the other circumferential groove, there was a risk of poor lubrication between the first and second circumferential grooves on the sliding surface, i.e., the radial center of the sliding surface.

This invention addresses these problems and aims to provide sliding parts with high lubricity.

To solve the aforementioned problems, the sliding component of the present invention is
A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space,
At least one of the sliding surfaces is
An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove,
The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove.
The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged to overlap when viewed from the circumferential direction .
The outer diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the outer diameter side dynamic pressure groove is in communication with the circumferential portion.
The inner diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the inner diameter side dynamic pressure groove is in communication with the circumferential portion .
According to this, the outer diameter side dynamic pressure generation mechanism and the inner diameter side dynamic pressure generation mechanism can be made larger in the radial direction, and the lands located on the inner diameter side of the outer diameter side dynamic pressure generation mechanism and the lands located on the outer diameter side of the inner diameter side dynamic pressure generation mechanism can be made smaller, thereby improving lubrication over the radial direction of the sliding surface.

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

This is a longitudinal cross-sectional view showing an example of a mechanical seal in Embodiment 1 of the present invention. This is a view of the sliding surface of the stationary sealing ring in Example 1, as seen from the axial direction. This is an enlarged view of the main part of Figure 2. This is a view of the sliding surface of the stationary sealing ring from the axial direction when the rotating sealing ring is rotating in the forward direction. This is a view of the sliding surface of the stationary sealing ring from the axial direction when the rotating sealing ring is rotating in the reverse direction. This is a view of the sliding surface of the stationary sealing ring in Embodiment 2 of the present invention, as seen from the axial direction. This figure shows a modified example of the sliding surface of the stationary sealing ring in Example 1 of the present invention.

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

The sliding component according to Example 1 will be described with reference to Figures 1 to 5. In this example, a mechanical seal will be used as an example of a sliding component. In this mechanical seal, a first fluid F1, such as oil, exists in the outer space S1 (outer diameter side space), and a second fluid F2, such as water, exists in the inner space S2 (inner diameter side space). For ease of explanation, dots may be added to grooves and other features formed on the sliding surface in the drawings.

The mechanical seal shown in Figure 1 is an inside-type seal that seals the first fluid F1 that is attempting to leak from the outer diameter side to the inner diameter side of the sliding surface. In other words, this describes an example where the first fluid F1 is at a higher pressure than the second fluid F2.

The mechanical seal mainly consists of a stationary sealing ring 10 and a rotating sealing ring 20. The stationary sealing ring 10 is annular in shape and is mounted on a seal cover 5 fixed to the housing 4 of the equipment to be mounted, in a non-rotatable state and movable in the axial direction. The rotating sealing ring 20 is annular in shape and is mounted on the rotating shaft 1 via a sleeve 2, allowing it to rotate with the rotating shaft 1. The stationary sealing ring 10 is biased in the axial direction by an elastic member 7. 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 grooves or other recesses.

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). However, the sliding material is not limited to these; any sliding material used for mechanical seals is applicable. SiC can be sintered using boron, aluminum, carbon, etc., as sintering aids, or from materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, SiC-TiN, etc. Carbon can be a mixture of carbonaceous and graphite, resin-molded carbon, sintered carbon, etc. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc., are also applicable.

As shown in Figure 2, the rotating sealing ring 20 slides relative to the stationary sealing ring 10 in a counterclockwise direction as indicated by the solid arrow and in a clockwise direction as indicated by the dashed arrow. Hereafter, the direction of the solid arrow will be described as the forward rotation direction of the rotating sealing ring 20, and the direction of the dashed arrow will be described as the reverse rotation direction of the rotating sealing ring 20.

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

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

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

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

The second portion 121b extends outward from one end of the first portion 121a, i.e., the downstream end of the relative rotation during forward rotation, and communicates with the outer space S1. In an axial view, this second portion 121b extends linearly outward from one end of the first portion 121a, inclined toward the downstream side of the relative rotation.

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

The first outer diameter circulation groove 121 has a symmetrical shape with respect to a virtual line β extending radially through the circumferential center of the first portion 121a.

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

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

The outer diameter side dynamic pressure groove 122b extends outward from one end of the communication groove 122a, i.e., the downstream end of the relative rotation during forward rotation, inclined toward the downstream side of the relative rotation, and then further extends circumferentially toward the downstream side of the relative rotation. In other words, the outer diameter side dynamic pressure groove 122b extends from one end of the communication groove 122a in a roughly inverted L-shape when viewed axially.

The outer diameter reverse dynamic pressure groove 122c extends outward from the other end of the communication groove 122a, i.e., the upstream end of the relative rotation during forward rotation, inclined toward the upstream side of the relative rotation, and then further extends circumferentially toward the upstream side of the relative rotation. In other words, the outer diameter reverse dynamic pressure groove 122c extends from the other end of the communication groove 122a in a roughly L-shape when viewed axially.

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

The second outer diameter side circulation groove 123 is located on the outer diameter side of the outer diameter side dynamic pressure generating element 122 in the region enclosed radially and circumferentially by the first outer diameter side circulation groove 121 and the outer space S1 on the sliding surface 11.

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

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

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

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

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

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

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

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

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

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

The first inner diameter circulation groove 131 has a symmetrical shape with respect to a virtual line β' extending radially through the circumferential center of the first portion 131a.

The inner diameter side dynamic pressure generating element 132 is formed in a region enclosed radially and circumferentially by the first inner diameter side circulation groove 131 and the inner space S2. The inner diameter side dynamic pressure generating element 132 includes a communication groove 132a, an inner diameter side dynamic pressure groove 132b, and an inner diameter side reverse dynamic pressure groove 132c.

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

The inner diameter-side dynamic pressure groove 132b extends inward from one end of the communication groove 132a, i.e., the downstream end of the relative rotation during forward rotation, while inclined toward the downstream side of the relative rotation, and then further extends circumferentially toward the downstream side of the relative rotation. In other words, the inner diameter-side dynamic pressure groove 132b extends from one end of the communication groove 132a in a substantially L-shape when viewed axially.

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

The internal diameter dynamic pressure generating element 132 has a symmetrical shape with respect to the imaginary line β'.

The second inner diameter side circulation groove 133 is located on the inner diameter side of the inner diameter side dynamic pressure generating element 132 in the region enclosed radially and circumferentially by the first inner diameter side circulation groove 131 and the inner space S2 on the sliding surface 11.

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

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

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

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

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

Next, the flow of the first fluid F1 and the second fluid F2 during relative rotation between the stationary sealing ring 10 and the rotating sealing ring 20 will be schematically explained with reference to Figures 4 and 5. Note that the relative rotational speeds of the stationary sealing ring 10 and the rotating sealing ring 20 will not be specified in this explanation.

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

Furthermore, when not rotating, the sliding surfaces 11 and 21 are in contact with each other, and virtually no mixing of the first fluid F1 and the second fluid F2 occurs between the sliding surfaces 11 and 21.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Furthermore, while the area between the second outer diameter circulation groove 123 and the outer diameter end of the sliding surface 11, and between the second inner diameter circulation groove 133 and the inner diameter end of the sliding surface 11 are lubricated by specific dynamic pressure generating elements 124 and 134, if the specific dynamic pressure generating elements 124 and 134, the second outer diameter circulation groove 123, and the second inner diameter circulation groove 133 are absent, lubrication can be achieved up to the outer diameter end by the outer diameter dynamic pressure groove 122b and up to the inner diameter end by the inner diameter dynamic pressure groove 132b.

Furthermore, because the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 are offset and overlapping in the circumferential direction, a large radial area can be secured for the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 on the sliding surface 11. This allows for a reduction in the size of the land 111 located on the inner diameter side of the outer diameter side dynamic pressure generating mechanism 12 and the land 112 located on the outer diameter side of the inner diameter side dynamic pressure generating mechanism 13. This, in turn, improves lubrication across the radial direction of the sliding surface 11.

Specifically, the outer diameter side dynamic pressure generation mechanism 12 can enhance lubrication using the first fluid F1, and the inner diameter side dynamic pressure generation mechanism 13 can enhance lubrication using the second fluid F2.

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

Furthermore, because the circumferential movement of the second fluid F2 supplied to land 111 and the first fluid F1 supplied to land 112 is greater due to the rotating sealing ring 20 than to the radial movement due to fluid pressure, the second fluid F2 is less likely to flow into the first outer diameter side circulation groove 121, and the first fluid F1 is less likely to flow into the first inner diameter side circulation groove 131.

Furthermore, the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 are arranged alternately in the circumferential direction. This arrangement ensures that the outer diameter side dynamic pressure generating mechanism 12 and the inner diameter side dynamic pressure generating mechanism 13 are balanced in the circumferential direction of the sliding surface 11. As a result, there are no areas that are consistently poorly lubricated in the radial direction when viewed from the circumferential direction, thus achieving nearly uniform lubrication in the circumferential direction.

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

Furthermore, referring to Figures 4 and 5, the adjacent first outer diameter circulation groove 121 has a second portion 121b and a third portion 121c extending from both sides of the first portion 121a, inclined away from the circumferential direction, and the first inner diameter circulation groove 131 has a second portion 131b and a third portion 131c extending from both sides of the first portion 131a, inclined away from the circumferential direction. This allows the closed end 122d of the outer diameter dynamic pressure groove 122b and the closed end 132e of the inner diameter dynamic pressure groove 132b to be spaced circumferentially by the circumferentially adjacent second portion 121b and third portion 131c. Furthermore, the circumferential distance between the circumferentially adjacent second portions 131b and the circumferential distance between the closure end 132d of the inner diameter dynamic pressure groove 132b and the closure end 122e of the outer diameter dynamic pressure groove 122b can be increased. This prevents the fluids that have flowed out between the sliding surfaces 11 and 21 from mixing.

Furthermore, the second portion 121b and the third portion 121c of the first outer diameter side circulation groove 121 communicate with the outer space S1, and the second portions 131b and 2nd portion 131b of the first inner diameter side circulation groove 131 communicate with the inner space S2. This arrangement ensures that during relative rotation, fluid constantly flows through the first outer diameter side circulation groove 121 and the first inner diameter side circulation groove 131. This flow allows the first fluid F1 recovered in the first outer diameter side circulation groove 121 to be returned to the outer space S1, and the second fluid F2 recovered in the first inner diameter side circulation groove 131 to be returned to the inner space S2, thus minimizing mixing of the fluids.

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

Furthermore, the outer diameter side dynamic pressure generation mechanism 12 includes an outer diameter side dynamic pressure groove 122b and an outer diameter side reverse dynamic pressure groove 122c, while the inner diameter side dynamic pressure generation mechanism 13 includes an inner diameter side dynamic pressure groove 132b and an inner diameter side reverse dynamic pressure groove 132c. This allows dynamic pressure to be generated in one side's dynamic pressure generation groove regardless of the rotation direction of the rotating sealing ring 20, and fluid to be recovered in the opposite side's dynamic pressure generation groove.

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

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

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

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

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

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

According to this, the annular deep groove 214 can recover the first fluid F1 moving from the outer space S1 to the inner space S2, and the second fluid F2 moving from the inner space S2 to the outer space S1. Therefore, it can prevent the inflow of the first fluid F1 into the inner space S2 and the inflow of the second fluid F2 into the outer space S1.

Furthermore, in this embodiment 2, since only one annular deep groove 214 is provided, a region prone to poor lubrication, as seen in the conventional configuration with two annular deep grooves in the radial direction, is not formed.

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

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 modifications or additions that do not depart from the spirit of the present invention are also included.

For example, in the above embodiments 1 and 2, the outer diameter side dynamic pressure generation mechanism and the inner diameter side dynamic pressure generation mechanism were exemplified as having radially symmetrical shapes, but they may also be asymmetrical.

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

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

Furthermore, while embodiments 1 and 2 illustrated a configuration where the outer diameter side dynamic pressure generating mechanism is positioned on the inner diameter side of the radial center of the sliding surface, and the inner diameter side dynamic pressure generating mechanism is positioned on the outer diameter side of the radial center of the sliding surface, it is sufficient for the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism to overlap in the circumferential direction. For example, one dynamic pressure generating mechanism does not need to extend radially away from the radial center of the sliding surface, nor does the other dynamic pressure generating mechanism need to extend radially away from the radial center of the sliding surface.

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

Furthermore, while the above-described embodiments 1 and 2 illustrated an example in which the outer diameter side dynamic pressure groove and the inner diameter side dynamic pressure groove communicate with the outer diameter side circulation groove and the inner diameter side circulation groove, they may not communicate with the outer diameter side circulation groove and the inner diameter side circulation groove as long as the fluid in the outer diameter side space and the fluid in the inner diameter side space can be introduced.

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

Furthermore, while embodiments 1 and 2 illustrate a configuration where the outer and inner diameter circulation grooves form a roughly trapezoidal shape in axial view, the invention is not limited to this configuration. For example, the shape can be freely changed to a roughly triangular or roughly arc-shaped configuration in axial view.

Furthermore, while embodiments 1 and 2 illustrate configurations in which a second outer diameter circulation groove and a second inner diameter circulation groove are provided, these configurations may be omitted. In this case, the outer diameter dynamic pressure groove and the inner diameter dynamic pressure groove may be directly connected to the outer diameter space and the inner diameter space. Additionally, the configurations of the second outer diameter circulation groove and the second inner diameter circulation groove, as well as the configurations of the specific dynamic pressure generating elements on the inner and outer diameter sides, may be omitted.

Furthermore, while embodiments 1 and 2 above illustrate configurations where the outer diameter side dynamic pressure generation mechanism and the inner diameter side dynamic pressure generation mechanism are compatible with both rotational directions, they may also be compatible with only one rotation.

For example, a configuration that accommodates one-way rotation, as shown in Figure 7, may also be used. The sliding surface 311 of the stationary sealing ring 310 is provided with four outer-diameter dynamic pressure generating mechanisms 312 and four inner-diameter dynamic pressure generating mechanisms 313. The outer-diameter dynamic pressure generating mechanism 312 consists of an outer-diameter circulation groove 321 and an outer-diameter dynamic pressure generating element 322. The inner-diameter dynamic pressure generating mechanism 313 consists of an inner-diameter circulation groove 331 and an inner-diameter dynamic pressure generating element 332.

The outer diameter side dynamic pressure generating element 322 has a substantially inverted L-shape, consisting of a portion extending outward from the first portion 321a of the outer diameter side circulation groove 321, and a portion extending downstream in the relative rotation direction in the positive rotation direction from the outer diameter end of said portion.

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

Furthermore, while mechanical seals were used as examples of sliding parts in Examples 1 and 2 above, other mechanical seals such as those used in general industrial machinery, automobiles, and water pumps may also be used. Moreover, the invention is not limited to mechanical seals; sliding parts other than mechanical seals, such as sliding bearings, may also be used.

1 Rotating shaft 4 Housing 10 Stationary sealing ring 11 Sliding surface 12 Outer diameter side dynamic pressure generating mechanism 13 Inner diameter side dynamic pressure generating mechanism 20 Rotating sealing ring 21 Sliding surfaces 111-113 Land 121 First outer diameter side circulation groove (outer diameter side circulation groove)
121a First part (circumferential part)
121b Second part (introduction part, derivation part)
121c Third part (introduction part, derivation part)
122 Outer diameter side dynamic pressure generating element 122b Outer diameter side dynamic pressure groove 122c Outer diameter side reverse dynamic pressure groove 124 Specific dynamic pressure generating element (dynamic pressure generating element)
131 First inner diameter side circulation groove (inner diameter side circulation groove)
131a First part (circumferential part)
131b Second part (introduction part, derivation part)
131c Third part (introduction part, derivation part)
132 Inner diameter side dynamic pressure generating element 132b Inner diameter side dynamic pressure generating groove 132c Inner diameter side reverse dynamic pressure groove 134 Specific dynamic pressure generating element (dynamic pressure generating element)
F1 First fluid F2 Second fluid S1 Outer space (outer diameter side space)
S2 Inner space (inner diameter side space)

Claims (7)

A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space,
At least one of the sliding surfaces is
An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove,
The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove.
The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged to overlap when viewed from the circumferential direction .
The outer diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the outer diameter side dynamic pressure groove is in communication with the circumferential portion.
The inner diameter side circulation groove comprises a circumferential portion extending in the circumferential direction, an introduction portion extending from one end of the circumferential portion while inclined to one side in the circumferential direction, and an outlet portion extending from the other end of the circumferential portion while inclined to the other side in the circumferential direction, and the inner diameter side dynamic pressure groove is in communication with the circumferential portion, making it a sliding component. A sliding component in which the sliding surfaces of a pair of sliding rings rotate relative to each other, thereby dividing an outer diameter space and an inner diameter space,
At least one of the sliding surfaces is
An outer diameter side dynamic pressure generating mechanism comprising an outer diameter side circulation groove and an outer diameter side dynamic pressure groove provided on the outer diameter side of the outer diameter side circulation groove and surrounded by the outer diameter side space and the outer diameter side circulation groove,
The internal diameter side dynamic pressure generating mechanism comprises an internal diameter side circulation groove located on the inner diameter side of the external diameter side circulation groove, and an internal diameter side dynamic pressure groove provided on the inner diameter side of the internal diameter side circulation groove and surrounded by the internal diameter side space and the internal diameter side circulation groove.
The outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged to overlap when viewed from the circumferential direction .
A sliding component having an annular groove extending in the circumferential direction formed between the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism . The sliding component according to claim 1 or 2 , wherein the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism are arranged alternately in the circumferential direction. The sliding component according to claim 1 or 2, wherein the outer diameter side dynamic pressure generating mechanism extends beyond the radial center of the sliding surface to the inner diameter side, and the inner diameter side dynamic pressure generating mechanism extends beyond the radial center of the sliding surface to the outer diameter side. At least one of the ends of the outer diameter side circulation groove communicates with the outer diameter side space,
The sliding part according to claim 1 or 2 , wherein at least one of the ends of the inner diameter side circulation groove is in communication with the inner diameter side space. The outer diameter side dynamic pressure generating mechanism has an outer diameter side reverse dynamic pressure groove extending in the circumferential direction opposite to the outer diameter side dynamic pressure groove,
The sliding component according to claim 1 or 2 , wherein the inner diameter side dynamic pressure generating mechanism has an inner diameter side reverse dynamic pressure groove extending in the circumferential direction opposite to the inner diameter side dynamic pressure groove. The sliding component according to claim 1 or 2 , wherein at least one of the outer diameter side dynamic pressure generating mechanism and the inner diameter side dynamic pressure generating mechanism is provided with a dynamic pressure generating element that communicates with the outer diameter side space or the inner diameter side space.