Patent Description:
Examples of a shaft sealing device preventing sealed fluid leakage include a mechanical seal and a slide bearing. The mechanical seal, the slide bearing, or the like includes sliding components rotating relative to each other and including a pair of sliding members such that sliding surfaces slide with each other. In such sliding components, the conditions of "sealing" and "lubrication" have to be met together in the interest of long-term sealability maintenance. In recent years in particular, it has been desired for environmental measures or the like to further reduce friction so that the energy that is lost due to sliding is reduced and sealed fluid leakage is prevented at the same time. The friction reduction can be achieved by inter-sliding surface dynamic pressure being generated by rotation and sliding being performed with a liquid film interposed.

For example, in the sliding component described in Patent Citation <NUM>, a plurality of dimples recessed in a cross-sectional view are provided in the entire region of the sliding surface of one of a pair of sliding members. When the pair of sliding members rotate relative to each other, a sealed fluid is supplied to the dimples provided in the sliding member, dynamic pressure is generated between the sliding surfaces, the sliding surfaces are slightly separated from each other, and the dimples hold the sealed fluid. As a result, the sliding surfaces can be slid with each other with a liquid film interposed between the sliding surfaces, and thus mechanical loss reduction and sealed fluid leakage prevention can be achieved at the same time. Patent Citation <NUM> discloses an oil-retaining sintered bearing formed from a sintered body of a powder metal so that pores are formed inside this body and other pores are open at the surface.

Although the lubricity between the sliding surfaces is enhanced by the dimples being provided in the sliding component of Patent Citation <NUM>, the depth of the dimples gradually decreases due to the wear of the sliding surfaces attributable to aging or the like, and then the sealed fluid cannot be sufficiently held and a decline in lubricity may arise between the sliding surfaces.

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 sustaining inter-sliding surface lubricity for a long time.

In order to solve the above problem, a sliding component is provided having the features of claim <NUM>. According to a first aspect of the present invention is a sliding component including a pair of sliding members, at least one of the sliding members being provided with: recessed portions formed in a sliding surface of the one of the sliding members; and hollow portions formed inside the one of sliding members so as to be out of alignment with the recessed portions in a thickness direction of the one of the sliding members. According to the aforesaid feature of the first aspect of the present invention, even when the sliding surface of the one of the sliding members wears to the thickness direction of the deepest recessed portion of the group of recessed portions, a new group of recessed portions including the plurality of recessed portions appears on the sliding surface, and thus the lubricity between the sliding surfaces can be sustained.

It may be preferable that a range of fluctuation of the volume of the group of recessed portions formed in the sliding surface is within <NUM>% while the one of the sliding members is worn by the thickness of the deepest recessed portion of the group of recessed portions. According to this preferable configuration, even when the sliding surface wears, the range of fluctuation of the volume of the group of recessed portions is as small as within <NUM>, and thus lubricity fluctuations depending on the degree of wear of the sliding surface can be suppressed.

According to the invention the hollow portions are disposed so as to overlap the recessed portions in part or in whole in a view from a direction orthogonal to the sliding surface. According to this preferable configuration, a significant fluctuation in the appearance position of the recessed portion in the sliding surface depending on the degree of wear of the sliding surface can be suppressed.

It may be preferable that the recessed portions of the group of recessed portions have different depths. According to this preferable configuration, the volume of the group of recessed portions appearing on the sliding surface is capable of approaching a constant volume regardless of the position of the sliding surface in the region of use of the one of the sliding members.

According to the invention throttle passages extending in the thickness direction allow the recessed portions and the hollow portions to communicate with each other. According to this configuration, a sealed fluid can be held in the recessed portion and the hollow portion. In addition, some of the wear debris on the sliding surface can be discharged to the hollow portion side via the throttle passage, and thus wear debris accumulation in the recessed portion can be suppressed.

Additionally, the throttle passages are formed at partially overlapping portions of the recessed portions and the hollow portions. According to this configuration, the sealed fluid or wear debris easily moves between the recessed portion and the hollow portion.

It may be preferable that the hollow portions are equal to each other in shape. According to this preferable configuration, the hollow portions are easily disposed such that the volume of the group of recessed portions appearing on the sliding surface is constant in the region of use.

Further, each of the hollow portions has at least a flat surface. According to this configuration, the hollow portions can be disposed with efficiency.

According to the invention, a base material of the one of the sliding members between adjoining two of the recessed portions continuously extends in the thickness direction from the sliding surface to a surface on a side opposite to the sliding surface. Thus, the strength of the sliding surface can be enhanced.

In order to solve the above problem, a sliding component according to an aspect of the present invention is a sliding component including a pair of sliding members, at least one of the sliding members being provided with: recessed portions formed in a sliding surface of the one of the sliding members, each of the recessed portions having a flat surface; and hollow portions formed inside the one of the sliding members so as to be disposed at a position deeper than the recessed portions, the hollow portions having flat surfaces and communicating with the recessed portions. According to the aforesaid feature of this aspect of the present invention, the hollow portions provided at the position deeper than the recessed portions appear on the sliding surface even when the sliding surface of the one of the sliding members wears and the recessed portions disappears. Accordingly, the lubricity between the sliding surfaces can be sustained.

It may be preferable that the hollow portions are positioned out of alignment with the recessed portions in a circumferential direction or a radial direction. According to this preferable configuration, the sealed fluid or wear debris easily moves between the recessed portion and the hollow portion.

It may be preferable configuration that the flat surfaces of the recessed portions are bottom surfaces of the recessed portions and the flat surfaces of the hollow portions are bottom surfaces of the hollow portions. According to this preferable configuration, the hollow portions can be disposed with efficiency.

It may be preferable that the hollow portions are positioned out of alignment in a circumferential direction or a radial direction in a state in which the hollow portions partially overlap bottom surfaces of the recessed portions in an axial direction and the hollow portions are continuously provided so as to communicate with the recessed portions at points overlapping the bottom surfaces of the recessed portions in the axial direction. According to this preferable configuration, the hollow portions can be disposed with efficiency and the sealed fluid or wear debris easily moves between the recessed portion and the hollow portion.

Further, a manufacturing method is disclosed which is a method of a sliding member provided with a group of recessed portions including a plurality of recessed portions formed in a sliding surface of the sliding member, and having a recessed shape in a cross-sectional view and a plurality of hollow portions formed inside the sliding member, the hollow portions being disposed so as to generate at least part of a new group of recessed portions until the sliding member is worn by a thickness of deepest one of the recessed portions, the method comprising steps of: laminating layers made of base material and each having holes; and coupling the layers together. According to the aforesaid feature of a third aspect of the present invention, even when the sliding surface of the one of the sliding members wears to the thickness direction of the deepest recessed portion of the group of recessed portions, a new group of recessed portions including the plurality of recessed portions appears on the sliding surface, and thus the lubricity between the sliding surfaces can be sustained. In addition, the plurality of hollow portions can be disposed at desired positions in the one sliding member by the predetermined material being formed while being laminated in the thickness direction of the one sliding member.

It may be preferable that the method of manufacturing the sliding member further comprises a step of forming throttle passage communicating the recessed portions and the hollow portions in a thickness direction of the sliding member. According to this preferable manner, the processing powder generated as a result of processing can be discharged from the hollow portion to the outside via the throttle passage, and thus the sliding member can be manufactured with ease and high accuracy.

The laminating step and the coupling step may be carried out by an additive manufacturing device. According to this manner, the sliding member can be manufactured with ease and high accuracy using a printer as the additive manufacturing device.

The laminating step and the coupling step, the layers may be laminated on a base member and integrated with the base member. According to this manner, the strength of the sliding member can be ensured by the base member and the manufacturing can be expedited.

Modes for implementing the sliding component and the method of manufacturing the sliding member according to the present invention will be described below based on embodiments.

The sliding component and the method of manufacturing the sliding member according to the first embodiment will be described with reference to <FIG>. It should be noted that a mode in which the sliding component is a mechanical seal will be described as an example in the present embodiment. In addition, in the following description, the outer peripheral side of the sliding component constituting the mechanical seal is a sealed fluid side and the inner peripheral side is an atmosphere side.

The mechanical seal for general industrial machinery illustrated in <FIG> is an inside-type mechanical seal that seals a sealed fluid to leak from the outer peripheral side toward the inner peripheral side of a sliding surface. The mechanical seal mainly includes a mating ring <NUM>, which is one circular ring-shaped sliding component provided on a rotary shaft <NUM> in a state of being rotatable integrally with the rotary shaft <NUM> via a sleeve <NUM>, and a circular ring-shaped seal ring <NUM>, which is the other sliding component provided on a seal cover <NUM> fixed to a housing <NUM> of an attached device in a non-rotating state and a state of being movable in the axial direction. A sliding surface <NUM> of the seal ring <NUM> and a sliding surface <NUM> of the mating ring <NUM> slide closely with each other by a bellows <NUM> urging the seal ring <NUM> in the axial direction. It should be noted that the sliding surface <NUM> of the seal ring <NUM> is a flat surface and the flat surface is not provided with a recessed portion.

The seal ring <NUM> and the mating ring <NUM> are typically formed of a combination of SiC (as an example of hard material) or a combination of SiC 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. It should be noted that a method for manufacturing the mating ring <NUM> will be described in detail later.

As illustrated in <FIG>, the mating ring <NUM> has the annular sliding surface <NUM> facing the sliding surface <NUM> of the seal ring <NUM> in the axial direction. The sliding surface <NUM> is a flat surface, and dimples <NUM> as recessed portions are formed in the entire surface in the circumferential direction to constitute a dimple group 22A as a group of recessed portions. Each dimple <NUM> has a circular shape when viewed from a direction orthogonal to the sliding surface <NUM> and has a recessed shape opening to the sliding surface <NUM> side in a radial cross-sectional view. In other words, the dimples <NUM> have a columnar shape having a central axis orthogonal to the sliding surface <NUM> (see <FIG> and <FIG>). It should be noted that the sliding surface <NUM> can be regarded as a land portion with respect to the dimple <NUM>.

Specifically, the dimple group 22A is configured by a row 23A in which four dimples <NUM> are disposed apart from the inner diameter side to the outer diameter side of the mating ring <NUM> and a row 23B in which five dimples <NUM> are disposed apart from the inner diameter side to the outer diameter side being alternately disposed in the circumferential direction and the two rows 23A and 23B are disposed radially from the center of the mating ring <NUM>. It should be noted that the plurality of dimples <NUM> are disposed in a zigzag shape in the circumferential direction of the sliding surface <NUM>.

<FIG> illustrates a state where the mating ring <NUM> is axially cut at the position of the row 23A. It should be noted that the row 23B is identical to the row 23A except for the number and thus the row 23B will not be described below.

The row 23A includes the dimple <NUM> with a depth dimension L1 and a dimple <NUM>' with a depth dimension L2 shallower than the dimple <NUM> (L1 > L2). The dimples <NUM> and <NUM>' are alternately arranged in the radial direction of the sliding surface <NUM>.

In the dimple <NUM>, a plurality of hollow portions 24a, 24b, 24c, and 24d are formed in the thickness direction of the mating ring <NUM> (hereinafter, simply referred to as the thickness direction in some cases) and a recessed unit 25A is configured by the dimple <NUM> and the hollow portions 24a, 24b, 24c, and 24d. Likewise, in the dimple <NUM>', a plurality of hollow portions 24a', 24b', 24c', and 24d' are arranged in parallel in the thickness direction and a recessed unit 25B is configured by the dimple <NUM>' and the hollow portions 24a', 24b', 24c', and 24d'.

The hollow portions 24a to 24d and the hollow portions 24a' to 24d' have the same depth dimension L3, and the depth dimension L3 of each hollow portion is equal to the depth dimension L1 of the dimple <NUM> that is a new product. In addition, the difference between the depth dimension L1 of the dimple <NUM> and the depth dimension L2 of the dimple <NUM>' is a dimension L4. In other words, the recessed unit 25A and the recessed unit 25B are disposed out of alignment with each other by the dimension L4 in the thickness direction of the mating ring <NUM>. It should be noted that the region of use in the thickness direction that can be used as the sliding surface <NUM> in the mating ring <NUM> is a region where any hollow portion is capable of appearing and functioning as a dimple even due to wear or the like and refers to the region from the sliding surface <NUM> to the bottom portion of the hollow portion 24d disposed in the deepest portion of the recessed unit 25A.

Next, the arrangement of the dimple <NUM> and the hollow portions 24a to 24d in the recessed unit 25A will be described with reference to <FIG>. It should be noted that the recessed unit 25B has the same configuration as the recessed unit 25A and thus the recessed unit 25B will not be described.

As illustrated in <FIG>, the hollow portion 24a is disposed out of alignment in the inner diameter direction of the dimple <NUM> and so as to be partially overlapped in the thickness direction and a passage 26a allows the dimple <NUM> and the hollow portion 24a to communicate with each other. Likewise, the hollow portion 24b is disposed out of alignment in the outer diameter direction of the hollow portion 24a and so as to be partially overlapped in the thickness direction and a passage 26b allows the hollow portion 24a and the hollow portion 24b to communicate with each other. In addition, the hollow portion 24c is disposed out of alignment in the inner diameter direction of the hollow portion 24b and so as to be partially overlapped in the thickness direction and a passage 26c allows the hollow portion 24b and the hollow portion 24c to communicate with each other. In addition, the hollow portion 24d is disposed out of alignment in the outer diameter direction of the hollow portion 24c and so as to be partially overlapped in the thickness direction and a passage 26d allows the hollow portion 24c and the hollow portion 24d to communicate with each other. In other words, the dimple <NUM> and the hollow portions 24a to 24d are alternately misaligned in the radial direction, are disposed in a zigzag shape in the thickness direction, and mutually communicate through the passages 26a to 26d.

In addition, an end surface 27a as the flat surface that is on the sliding surface <NUM> side in the hollow portion 24a is disposed at the same position in the thickness direction as a bottom surface 22a as a flat surface of the dimple <NUM> and the passage 26a is formed by the end surface 27a and the bottom surface 22a partially overlapping in the radial direction. In other words, the passage 26a is formed by the opening point of the end surface 27a and the opening point of the bottom surface 22a overlapping. Likewise, in the hollow portions 24b to 24d, end surfaces 27b to 27d on the sliding surface <NUM> side are disposed at the same positions in the thickness direction as bottom surfaces 28a to 28c of the hollow portions 24a to 24c adjacent to the sliding surface <NUM> side and the passages 26b to 26d are formed by the end surfaces 27b to 27d and the bottom surfaces 28a to 28c partially overlapping in the radial direction. In other words, the passages 26a to 26d are throttle passages smaller than the radial cross-sectional area of the dimple <NUM> and the hollow portions 24a to 24d.

More specifically, as illustrated in <FIG>, the dimple <NUM> and the hollow portions 24b and 24d are disposed so as to overlap when viewed from the direction orthogonal to the sliding surface <NUM> and the hollow portions 24a and 24c are disposed so as to overlap when viewed from the direction orthogonal to the sliding surface <NUM> at positions misaligned to the inner diameter side of the dimple <NUM> and the hollow portions 24b and 24d.

Next, a change in the degree of wear of the mating ring <NUM> will be described with reference to <FIG> and <FIG>. <FIG> is a view cut at the A-A position in <FIG> and illustrates a state where the seal ring <NUM> and the mating ring <NUM> are new products. When the seal ring <NUM> and the mating ring <NUM> rotate relative to each other from the state of <FIG>, the dimples <NUM> and <NUM>' form a film of the sealed fluid between the sliding surfaces <NUM> and <NUM> and satisfactory lubrication can be maintained. This is because the dimple group 22A is designed to have the optimal volume for maintaining the lubricity between the sliding surfaces <NUM> and <NUM> (see point P1 in <FIG>).

As illustrated in <FIG>, the volume of the dimple group 22A configured by the dimples <NUM> and <NUM>' gradually decreases as the sliding surface <NUM> wears due to aging or the like (see the section between points P1 and P2 in <FIG>). However, when the dimple <NUM>' has disappeared (see point P2 in <FIG>), the wall portion constituting an end surface 27a' of the hollow portion 24a' on the sliding surface <NUM> side is scraped and the hollow portion 24a' opens to the seal ring <NUM> side. In other words, the hollow portion 24a' appears as a new dimple and, as a result, the volume of the dimple group 22A increases to a volume close to the volume in the new product state (see point P3 in <FIG>).

When the sliding surface <NUM> further wears subsequently as illustrated in <FIG>, the volume of the dimple group 22A configured by the dimple <NUM> and the hollow portion 24a' gradually decreases (see the section between points P3 and P4 in <FIG>). However, when the dimple <NUM> has disappeared, the wall portion constituting the end surface 27a of the hollow portion 24a is scraped and the hollow portion 24a opens to the seal ring <NUM> side. In other words, the hollow portion 24a appears as a new dimple and, as a result, the volume of the dimple group 22A increases to a volume close to the volume in the new product state (see point P5 in <FIG>).

In this manner, the volume of the dimple group 22A always falls within an allowable fluctuation range in the region of use of the mating ring <NUM> even when the sliding surface <NUM> of the mating ring <NUM> wears, and thus poor lubrication does not arise between the sliding surfaces <NUM> and <NUM>, a decline in lubricity or sealability attributable to excessive buoyancy generation between the sliding surfaces <NUM> and <NUM> can be prevented, and the lubricity between the sliding surfaces <NUM> and <NUM> can be preferably sustained.

In addition, the range of fluctuation of the volume of the dimple group 22A appearing on the sliding surface <NUM> is within <NUM>. Since the range of fluctuation is small, lubricity fluctuations depending on the degree of wear of the sliding surface <NUM> can be suppressed. It should be noted that the dimple group 22A appearing on the sliding surface <NUM> in the region of use of the mating ring <NUM> may be formed by a different number (two or more) of hollow portions although a mode in which the dimple group 22A is formed by the same number of hollow portions in the region of use of the mating ring <NUM> is exemplified in the first embodiment. In the region of use of the mating ring <NUM>, the range of fluctuation of the volume of the dimple group 22A appearing on the sliding surface <NUM> may be preferably within <NUM>% and may be preferably within <NUM>.

In addition, the hollow portions 24a to 24d and the hollow portions 24a' to 24d' constituting the recessed units 25A and 25B are disposed so as to overlap the dimples <NUM> and <NUM>' in part or in whole when viewed from the direction orthogonal to the sliding surface <NUM>. Accordingly, the positions of the hollow portions 24a to 24d and the hollow portions 24a' to 24d' appearing as dimples do not significantly fluctuate in the radial and circumferential directions of the sliding surface <NUM> depending on the degree of wear of the sliding surface <NUM> and a film of the sealed fluid can be evenly generated between the sliding surfaces <NUM> and <NUM>.

Further, the occupied areas of the recessed units 25A and 25B in the radial and circumferential directions can be reduced when viewed from the direction orthogonal to the sliding surface <NUM>, and thus multiple recessed units 25A and 25B can be disposed in the mating ring <NUM>.

In addition, the hollow portions 24a to 24d and 24a' to 24d' of the recessed units 25A and 25B are alternately misaligned in the radial direction and disposed in a zigzag shape in the thickness direction with respect to the respective dimples <NUM> and <NUM>' and the recessed units 25A and 25B are misaligned in the thickness direction. In other words, the dimple group 22A is configured by the plurality of dimples <NUM> and <NUM>' with different depths, and thus the mating ring <NUM> can be configured such that the volume of the dimple group 22A appearing on the sliding surface <NUM> approaches a constant volume regardless of the position of the sliding surface <NUM> in the region of use of the mating ring <NUM>.

In addition, the passages 26a to 26d extending in the thickness direction allow the dimples <NUM> and <NUM>' and the hollow portions 24a to 24d and 24a' to 24d' to communicate. Accordingly, a large amount of sealed fluid can be held in the dimples <NUM> and <NUM>' and the hollow portions 24a to 24d and 24a' to 24d'. In addition, some of the wear debris on the sliding surface <NUM> can be discharged and stored on the hollow portion 24a to 24d and 24a' to 24d' sides via the passages 26a to 26d, and thus lubricity impairment between the sliding surfaces <NUM> and <NUM> attributable to wear debris accumulation in the dimples <NUM> and <NUM>' can be suppressed. In addition, the hollow portions 24a to 24d and 24a' to 24d' have a labyrinth structure, and thus it is difficult for the wear debris stored in the hollow portions 24a to 24d and 24a' to 24d' to return to the dimples <NUM> and <NUM>'. In particular, it is difficult for the wear debris stored on the hollow portion <NUM> and 24d' sides to return to the dimples <NUM> and <NUM>'.

Further, the passages 26a to 26d are configured by the dimples <NUM> and <NUM>' and the hollow portions 24a to 24d and 24a' to 24d' overlapping in part, and thus the sealed fluid or wear debris easily moves between the dimples <NUM> and <NUM>' and the hollow portions 24a to 24d and 24a' to 24d'. In addition, the dimples <NUM> and <NUM>' and the hollow portions 24a to 24d and 24a' to 24d' do not have to form a separate throttle passage, and thus the recessed units 25A and 25B are formed with ease.

In addition, the hollow portions 24a to 24d and 24a' to 24d' have the same shape, and thus the hollow portions 24a to 24d and 24a' to 24d' are easily disposed such that the volume of the dimple group 22A appearing on the sliding surface <NUM> is constant in the region of use.

Further, the hollow portions 24a to 24d and 24a' to 24d' have the flat end surfaces 27a to 27c and the bottom surfaces 28a to 28c. Accordingly, multiple hollow portions 24a to 24d and 24a' to 24d' can be disposed by the end surfaces 27a to 27c and the bottom surfaces 28a to 28c being brought close to each other, that is, can be efficiently disposed in a small space.

In addition, each of the hollow portions 24a to 24d and 24a' to 24d' is formed in a columnar shape having a central axis orthogonal to the sliding surface <NUM> and the opening region of each of the hollow portions 24a to 24d and 24a' to 24d' does not change depending on the degree of wear of the sliding surface <NUM>. Accordingly, the hollow portions 24a to 24d and 24a' to 24d' are easily disposed such that the volume of the dimple group 22A is constant.

In addition, a base material 20A of the mating ring <NUM> between the dimples <NUM> and <NUM>' adjacent in the radial or circumferential direction continuously extends in the thickness direction, in a pillar shape, and with a certain width from the sliding surface <NUM> to a base member 20B (see <FIG>, described later) positioned on the side opposite to the sliding surface <NUM>. Accordingly, the sliding surface <NUM> can be supported with high strength.

Next, a method for manufacturing the mating ring <NUM> will be described with reference to <FIG>. The mating ring <NUM> in the present embodiment is manufactured by a lamination shaping method using a 3D printer, which is a type of additive manufacturing device. It should be noted that the thickness of the layer of SiC powder M, which is a predetermined material to be spread, illustrated in <FIG> exceeds the actual thickness so that understanding of the description is facilitated.

Specifically, as illustrated in <FIG>, the base member 20B having a predetermined thickness and forming a circular plate shape when viewed from the thickness direction is disposed on the pedestal of the 3D printer and the SiC powder M is spread so as to cover the base member 20B as a whole.

Then, as illustrated in <FIG>, the base material 20A in the mating ring <NUM> is laminated and connected in the thickness direction of the base member 20B by the SiC powder M being melted and solidified by a heat source (not illustrated) such as a laser. At this time, in the laminated SiC powder M, parts other than the parts (specific regions) that become the hollow portions are melted and solidified.

As illustrated in <FIG>, the step of spreading the SiC powder M and the step of melting and solidifying the SiC powder M are repeated until the mating ring <NUM> reaches a desired thickness. When the mating ring <NUM> reaches the desired thickness, the SiC powder M remaining in the hollow portions 24a to 24d and 24a' to 24d' and the dimples <NUM> and <NUM>' is discharged out of the opening portions of the dimples <NUM> and <NUM>' and the manufacturing is completed.

In this manner, the base material 20A is formed by the SiC powder M being laminated and connected in the thickness direction of the mating ring <NUM> in the region (predetermined material) other than the hollow portions 24a to 24d and 24a' to 24d' and the dimples <NUM> and <NUM>'. As a result, the mating ring <NUM> in which the plurality of hollow portions 24a to 24d and 24a' to 24d' and the dimples <NUM> and <NUM>' are disposed at desired positions can be formed.

In addition, the passages 26a to 26d allow the hollow portions 24a to 24d and 24a' to 24d' and the dimples <NUM> and <NUM>' to communicate as described above. Accordingly, the unnecessary SiC powder M in the hollow portions 24a to 24d and 24a' to 24d' can be discharged to the outside via the passages 26a to 26d and the mating ring <NUM> can be manufactured with ease and high accuracy by the 3D printer-based lamination shaping method. By the mating ring <NUM> being manufactured in this manner, the SiC powder M during the manufacturing does not appear even when the hollow portion becomes a dimple due to wear during the use of the mating ring <NUM>.

In addition, the SiC powder M is laminated and integrated on the base member 20B, and thus the strength of the mating ring <NUM> can be ensured by the base member 20B and the manufacturing can be expedited. It should be noted that the mating ring <NUM> may be manufactured directly on the pedestal without the base member 20B being used although a mode in which the SiC powder M is laminated and connected on the base member 20B has been exemplified.

In addition, a dimple <NUM> and hollow portions 241a to 241d may be spherical as illustrated in, for example, <FIG> although a mode in which each dimple and each hollow portion are formed in a columnar shape having a central axis orthogonal to the sliding surface has been exemplified in the first embodiment. It should be noted that the dimple and the hollow portions may be, for example, grooves having a conical shape, a triangular pyramid shape, or a recessed shape that is long in the circumferential or radial direction.

In addition, dimples <NUM> and <NUM>' and hollow portions <NUM> may be independently provided so as not to communicate and so as to overlap in the thickness direction when viewed from the circumferential direction as illustrated in <FIG> although the dimple and the hollow portion are interconnected by the throttle passage in the first embodiment. It should be noted that a throttle flow path (not illustrated) having a predetermined length may allow the independent dimples <NUM> and <NUM>' and hollow portions <NUM> to communicate with each other.

In addition, a dimple <NUM> and hollow portions 243a to 243d may be spirally disposed toward the thickness direction as illustrated in <FIG> although a mode in which the dimple <NUM> and the hollow portions 24b and 24d in the recessed unit 25A are disposed so as to overlap when viewed from the direction orthogonal to the sliding surface <NUM> and the hollow portions 24a and 24c overlap when viewed from the direction orthogonal to the sliding surface <NUM> and are disposed so as to be misaligned to the inner diameter side of the dimple <NUM> and the hollow portions 24b and 24d has been exemplified in the first embodiment. Specifically, the dimple <NUM> and the hollow portion 243c may overlap when viewed from the direction orthogonal to the sliding surface <NUM>, the hollow portions 243a and 243d may overlap when viewed from the direction orthogonal to the sliding surface <NUM> at positions out of alignment with the dimple <NUM> and the hollow portion 243c in the radial direction, and the hollow portion 243b may be disposed at a position out of alignment with the dimple <NUM> and the hollow portions 243a, 243c, and 243d in the radial direction when viewed from the direction orthogonal to the sliding surface <NUM>.

In addition, the recessed unit 25A and the recessed unit 25B may be disposed at the same positions in the thickness direction although a mode in which the recessed unit 25A and the recessed unit 25B are disposed out of alignment in the thickness direction of the mating ring <NUM> has been exemplified in the first embodiment. Even in this case, the recessed units 25A and 25B respectively communicate in the thickness direction, and thus a state where the dimple group is not formed in the region of use of the mating ring <NUM> can be avoided. In other words, a dimple group may be formed that has a volume within a predetermined range at which the sealed fluid can be appropriately held with the sliding surfaces <NUM> and <NUM> appropriately separated from each other in the region of use of the mating ring <NUM>.

Next, the sliding component according to the second embodiment of the present invention will be described with reference to <FIG>. It should be noted that description of configurations identical to those of the first embodiment is omitted for redundancy avoidance. It should be noted that only the mode of the row 23A will be described here.

As illustrated in <FIG>, in the row 23A of a mating ring <NUM> partially forming a sliding component according to the second embodiment of the present invention, a communication passage <NUM> allows the recessed units 25A to communicate with each other and a communication passage <NUM> allows the recessed units 25B to communicate with each other.

The communication passage <NUM> allows the hollow portions 24d disposed in the deepest portions of the recessed units 25A to communicate with each other. The communication passage <NUM> is formed by a plurality of hollow portions 12a being connected in a V-shaped cross section. In addition, the communication passage <NUM> allows the hollow portions 24d' disposed in the deepest portions of the recessed units 25B to communicate with each other. The communication passage <NUM> is formed by a plurality of hollow portions 13a being connected in a V-shaped cross section. According to this, a large amount of sealed fluid can be held in the communication passages <NUM> and <NUM> and the wear debris on the sliding surface <NUM> can be discharged to the communication passages <NUM> and <NUM>. Accordingly, wear debris accumulation in the dimples <NUM> and <NUM>' can be suppressed.

Next, a first modification example of the sliding component according to the second embodiment will be described. As illustrated in <FIG>, the deepest portions of communication passages <NUM> and <NUM> extend in the radial direction so as to be orthogonal to the axial direction (thickness direction) of a mating ring <NUM> and have a U-shaped cross section. In this manner, the shapes of the communication passages <NUM> and <NUM> can be freely changed.

Next, a second modification example of the sliding component according to the second embodiment will be described. As illustrated in <FIG>, communication passages <NUM> and <NUM> have communication groove portions 122a and 132a extending from the deepest portions of the communication passages <NUM> and <NUM> to the outer diameter side of a mating ring <NUM>. According to this, the sealed fluid can be drawn into the communication passages <NUM> and <NUM> through the communication groove portions 122a and 132a and the wear debris on the sliding surface <NUM> can be discharged to the sealed fluid side through the communication groove portions 122a and 132a. The drawing and discharging of the sealed fluid through the communication groove portions 122a and 132a change depending on the depth of the dimple appearing on the sliding surface <NUM>.

Next, the sliding component according to the third embodiment of the present invention will be described with reference to <FIG> and <FIG>. It should be noted that description of configurations identical to those of the first embodiment is omitted for redundancy avoidance.

As illustrated in <FIG> and <FIG>, a row 231A of a mating ring <NUM> is configured by dimples <NUM> and <NUM>' of recessed units 251A and 251B disposed out of alignment in the thickness direction being alternately disposed in the radial direction.

The dimple <NUM> of the recessed unit 251A has an opening portion formed in a semicircular shape when viewed from the direction orthogonal to the sliding surface <NUM>. A wall portion 224a on the side opposite to the turning direction of the mating ring <NUM> (see the white arrow in <FIG>) is formed so as to extend in the thickness direction so as to be orthogonal to the direction of rotation. A curved wall portion 224b on the turning direction side is formed in a tapered shape that tapers toward the thickness direction.

In addition, hollow portions 244a to 244d have the same shape as the dimple <NUM> and are disposed so as to overlap in the thickness direction. In other words, the dimple <NUM> and the hollow portions 244a to 244d are respectively tapered toward the thickness direction, and thus the overlapping parts of the dimple <NUM> and the hollow portions 244a to 244d are throttle flow paths 261a to 261d.

In addition, the dimple <NUM>' of the recessed unit 251B is formed so as to be shallower in depth dimension than the dimple <NUM> and hollow portions 244a' to 244d' have the same shape as the dimple <NUM> and the hollow portions 244a to 244d.

According to this, the sealed fluid is capable of flowing in smoothly from the wall portion 224b and 224b' sides of the dimples <NUM> and <NUM>' along the tapered shape, and thus a dynamic pressure generation effect can be enhanced. In addition, the dimple <NUM> and the hollow portions 244a to 244d are linearly disposed in the plate thickness direction, and thus multiple recessed units 251A and 251B can be disposed with efficiency.

In addition, the following is a modification example of the sliding component of the third embodiment. As illustrated in <FIG>, a hemispherical liquid holding portion <NUM> is formed across the wall portion 224a on the side opposite to the dimple <NUM> in the turning direction. In addition, the liquid holding portions <NUM> are also formed on the sides opposite to the hollow portions 244a to 244d in the direction of rotation across wall portions 270a to 270d of the hollow portions 244a to 244d. Through holes <NUM> are respectively formed in the wall portion 224a and the wall portions 270a to 270d. As a result, the dimple <NUM> communicates with the liquid holding portion <NUM> and the wall portions 270a to 270d respectively communicate with the liquid holding portions <NUM>.

According to this, the sealed fluid can be held in the liquid holding portion <NUM> when the sliding surface <NUM> is worn and the liquid holding portion <NUM> is open. In addition, the sealed fluid is capable of flowing in through the through hole <NUM> to the dimple <NUM> side. Accordingly, the sealed fluid holding capacity of the dimple <NUM> is improved.

Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to the embodiments and any changes or additions within the scope of the present invention are included in the present invention.

For example, although the mechanical seal for general industrial machinery has been described as an example of the sliding component in the above embodiments, the mechanical seal may be replaced with another mechanical seal for an automobile, a water pump, or the like. In addition, the mechanical seal may be an outside-type mechanical seal.

In addition, although an example in which the dimple and the hollow portion are provided only in the mating ring has been described in the above embodiments, the dimple and the hollow portion may be provided only in the seal ring or may be provided in both the seal ring and the mating ring.

In addition, the generated dynamic pressure increases when the dimples are too large in number and the change in the dynamic pressure acting over the circumferential direction of the sliding surface increases when the dimples are too small in number. Accordingly, it is preferable to appropriately set the number in accordance with the environment of use and so on.

In addition, although the mechanical seal has been described as an example of the sliding component, the sliding component may be a non-mechanical seal sliding component such as a slide bearing.

In addition, although a mode in which a sliding member is formed using a 3D printer as an additive manufacturing device ejecting and depositing a material has been exemplified in the above embodiments, the additive manufacturing method is not limited thereto. For example, a sliding member having a plurality of hollow portions in the thickness direction may be formed by laminating and connecting uneven plate material using a sheet lamination device.

Claim 1:
A sliding component comprising a pair of sliding members (<NUM>, <NUM>), at least one of the sliding members (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) being provided with:
recessed portions (<NUM>, <NUM>', <NUM>, <NUM>) formed in a sliding surface (<NUM>, <NUM>) of the one of the sliding members, each of the recessed portions having a flat surface; and
hollow portions (24a, 24b, 24c, 24d, 24a', 24b', 24c', 24d', 243a, 243b, 243c, 243d, 244a, 244b, 244c, 244d, 244a', 244b', 244c', 244d') formed inside the one of the sliding members so as to be disposed at a position deeper than the recessed portions in an axial direction, each of the hollow portions having a flat surface (27a, 27b, 27c, 27d, 28a, 28b, 28c, 28d), wherein
a base material (20A, 20B) forming the one of the sliding members exists a1 least between the sliding surface and the hollow portions in the axial direction,
the base material of the one of the sliding members between adjoining two of recessed units (25A, 25B, 251A, 251B) continuously extends in the thickness direction from the sliding surface to a surface on a side opposite to the sliding surface, characterized in that
each of the recessed portions and one of the hollow portions communicate with each other through a throttle passage (26a, 26b, 26c, 26d, 261a, 261b, 26lc, 261d) which is formed by overlapping the hollow portion and the recessed portion in a view from a direction orthogonal to the sliding surface,
the recessed portion and the hollow portion which are connected to each other through the throttle passage configure the recessed unit (25A, 25B, 251A, 251B).