JP5122607B2 - Flat sliding mechanism - Google Patents

Description

  The present invention relates to a planar sliding mechanism.

  A plane sliding mechanism that slides between opposing planes is used as, for example, a sealing device applied to a shaft seal portion of a high-pressure fluid device.

  As a non-contact type mechanical seal, a rotating member of a shaft-sealed device, a rotating sealing ring that rotates simultaneously with the rotating member, and a stationary sealing ring that is held unrotatable and is always biased to the rotating sealing ring side by a spring. (Patent Document 1). In Patent Document 1, a plurality of narrow and deep bottom fluid introduction grooves extending in the radial direction at equal intervals in the circumferential direction are formed on the seal surface of the rotary seal ring, communicated with each of these fluid introduction grooves, and circular A wide and shallow dynamic pressure generating groove extending in one of the circumferential directions is formed. When the rotating seal ring rotates, the fluid on the high pressure side flows into the dynamic pressure generating groove from the fluid introduction groove and generates a dynamic pressure between the seal surface of the stationary seal ring, for example, a narrow seal gap of about 5 to 20 μm. It is configured to seal the low pressure side and the high pressure side in a non-contact state.

  In Patent Document 1, the ratio of the dimension from the radially outer side of the seal surface to the radially inner side of the dynamic pressure generating groove and the radial width of the seal surface, and the density of the carbon material constituting the stationary seal ring In addition, the self-alignment function of the seal gap is provided by setting the Young's modulus to a predetermined value.

JP-A-5-60247

  Since the thing of patent document 1 restrict | limits the mechanical characteristic of material, a material becomes limited. In addition, when it is difficult to form an oil film having a sufficient thickness, such as when the load of the mating member is large or when the sliding speed is low, the oil film is cut off and seizure is likely to occur. Further, even when an oil film having a sufficient thickness is formed, the oil film thickness is likely to vary due to speed fluctuations and load fluctuations, and sufficient oil film rigidity cannot be obtained. As described above, since the oil film thickness varies greatly depending on the sliding conditions, fluid leakage or seizure may occur.

  In view of the above circumstances, the present invention provides a flat sliding mechanism that can stably obtain a thin oil film and has high sealing performance.

The present invention is a plane sliding mechanism that performs relative rotational sliding between opposing planes through a film of lubricating fluid, and seals the inner diameter side and the outer diameter side. A ring-shaped slide between the opposing planes that opens to one of the inner diameter side or the outer diameter side and has an end in the opposite radial direction to the opening in the plane. A fluid introduction groove to be introduced into the region, and shallower than the fluid introduction groove, communicated with the fluid introduction groove, and inclined in parallel with the sliding direction of the other flat surface or at an inclination angle of less than 90 °. A plurality of shallow grooves having periodicity in the direction, and the one fluid introduction groove and the plurality of shallow grooves communicating with the one fluid groove constitute a groove structure, and the groove structure is symmetrical with respect to the radial axis. The plurality of shallow grooves are arranged symmetrically with respect to the axis, and are formed at a pitch of 10 μm or less. In addition, it is formed to a depth of 1 μm or less .

The present invention has been made paying attention to the relationship between the depth dimension of the groove provided on the plane and the thickness dimension of the lubricating fluid film, and the fluid introduction groove and the shallow groove having different groove depths intersect each other. In addition, by arranging the relatively shallow grooves in a predetermined manner, a stable oil film can be formed regardless of the sliding speed and the load. That is, by arranging a plurality of shallow grooves provided in one of the planes that slide relative to each other with periodicity, and arranging the plurality of shallow grooves arranged in parallel so as to intersect with the fluid introduction grooves. The fluctuation range of the thickness of the lubricating fluid film formed between the planes is reduced, and the fluctuation range of the friction coefficient is reduced by stably obtaining a thin film thickness of several μm or less. This is considered due to the following actions. That is, by arranging a plurality of shallow grooves so as to intersect with one fluid introduction groove as described above, the lubricating fluid causes the plurality of shallow grooves from the fluid introduction groove to hardly cause side leakage. To the flat surface (the shallow groove non-forming portion). At this time, the load capacity is developed by the hydraulic pressure rising at the boundary between the shallow groove forming portion and the shallow groove non-forming portion. At this time, when the film thickness is relatively large, the rise of hydraulic pressure due to the shallow groove (dynamic pressure effect) hardly occurs, and the presence of the shallow groove reduces the dynamic pressure effect due to the fluid introduction groove. It acts in the direction of reducing the film thickness. Further, when the film thickness is relatively small, the lubricating fluid flows mainly along the longitudinal direction of the shallow groove, and a large dynamic pressure effect is generated at the end portion on the anti-fluid introduction groove side. The dynamic pressure effect is greater when the groove depth is closer to the oil film thickness, and is maximized when the groove depth is the same. Therefore, when the oil film thickness is small, a highly rigid fluid film can be formed by the shallow groove. As a result, it is considered that the fluctuation range of the film thickness of the lubricating fluid becomes small.
Further, since the plurality of shallow grooves are formed with a pitch of 10 μm or less, it is possible to further prevent the side leakage of the lubricating fluid and further increase the effect of generating the dynamic pressure. As a result, the pressure drop on the side can be reduced and the rolling error can be reduced.
Furthermore, the shallow groove is formed to a depth of 1 μm or less. That is, by forming the shallow groove in a size smaller than the order of a general dynamic pressure groove (several μm to several tens μm), it is possible to reduce the fluctuation of the flying height when the dynamic pressure is generated and to improve the rigidity. In particular, a highly rigid fluid film can be formed by exhibiting an excellent dynamic pressure effect in a sliding region where the film thickness is 1 μm or less.

  The plurality of shallow grooves may be arranged in a circumferential direction or a tangential direction of the rotation direction. Thereby, the lubricating fluid can be efficiently taken into the shallow groove from the fluid introduction groove, and the load capacity can be increased.

  Regarding the planar sliding mechanism according to the above configuration, for example, the plurality of shallow grooves irradiate one plane with a linearly polarized laser beam with an irradiation intensity in the vicinity of the processing threshold, and perform scanning while overlapping the irradiated portions. It may be formed automatically. Details are given in Japanese Patent Publication No. 4054330. According to this type of so-called laser-based self-organized parallel groove forming method, both pitch and groove depth of the order of 1 μm or less, which are difficult to machine, are obtained. The shallow groove group can be easily formed.

  As described above, according to the present invention, a thin oil film can be stably obtained regardless of the sliding speed, the magnitude of the load, and the material, and the oil film thickness variation is small and the oil film rigidity is excellent. A moving mechanism can be provided. Thereby, a high sealing performance can be obtained between the inner diameter side and the outer diameter side.

It is a top view which shows one plane of the plane sliding mechanism which concerns on one Embodiment of this invention. It is AA sectional drawing of the plane sliding mechanism shown in FIG. 1, Comprising: It is sectional drawing which shows notionally the sliding state in case an oil film thickness is comparatively large. It is AA sectional drawing of the plane sliding mechanism shown in FIG. 1, Comprising: It is sectional drawing which shows notionally the sliding state in case an oil film thickness is comparatively small. It is a principal part top view which shows one plane of the plane sliding mechanism which concerns on other embodiment of this invention. It is a principal part top view which shows one plane of the plane sliding mechanism which concerns on other embodiment of this invention. It is a principal part top view which shows one plane of the plane sliding mechanism which concerns on other embodiment of this invention. It is a principal part top view which shows one plane of the plane sliding mechanism which concerns on other embodiment of this invention. It is a top view which shows one plane of the plane sliding mechanism which concerns on other embodiment of this invention. It is a top view which shows one plane of the plane sliding mechanism which concerns on other embodiment of this invention. It is a figure which shows the result of a sliding experiment, Comprising: It is a figure which shows the relationship between the sliding speed and dynamic friction coefficient of the plane sliding mechanism which concerns on a comparative example. It is a figure which shows the result of a sliding experiment, Comprising: It is a figure which shows the relationship between the sliding speed and dynamic friction coefficient of the plane sliding mechanism which concerns on an Example. It is a figure which shows the result of a sliding experiment, Comprising: It is a figure which shows the relationship between the sliding speed and the dynamic friction coefficient when the load of the plane sliding mechanism which concerns on an Example is varied. It is a figure which shows the result of a sliding experiment, Comprising: It is a figure which shows the relationship between the sliding speed and oil film thickness when the load of the plane sliding mechanism which concerns on an Example is varied.

  Hereinafter, an embodiment of a plane sliding mechanism according to the present invention will be described with reference to FIGS.

  FIG. 1: has shown the principal part top view of the plane sliding mechanism which concerns on one Embodiment of this invention. The plane (first sliding surface) 1a of the first member 1 and the plane (second sliding surface) 2a of the second member 2 are relatively rotated and slid through the lubricating fluid, for example, Can be used for oil seals. In this case, as shown in FIG. 1, the first member 1 is a ring body, and the second member 2 is a disk body. The outer diameter side of the ring body is the high pressure side where the lubricating fluid is present, and the inner diameter side is the low pressure side where the gas is present, and seals the inner diameter side and the outer diameter side. In addition, various fluids, such as water, oil, and a liquid metal, can be selected as a lubricating fluid, and can be variously changed according to the use for which this sliding surface structure is used.

  As shown in FIG. 1, a fluid introduction groove 3 to be described later is formed on the first sliding surface 1a constituting the flat sliding mechanism at predetermined intervals along the circumferential direction (90 ° in the present embodiment). And four groove structure bodies 5 constituted by a plurality of shallow grooves 4 are formed. The groove structure 5 is line-symmetric with the radial axis of the first sliding surface 1a as the symmetry axis S.

  The fluid introduction groove 3 is a groove for supplying a lubricating fluid (for example, lubricating oil here) between the opposing flat surfaces 1a and 2a. In this embodiment, the fluid introduction groove 3 has a linear shape extending in the radial direction, and is arranged in a direction perpendicular to the sliding direction of the other opposing flat surface 2a (having the mating member 2). One end of the fluid introduction groove 3 opens to the outer diameter edge 6 of the plane 1a, and the other end exists in the plane. Therefore, the inside of the fluid introduction groove 3 is not in communication with the outside air.

  As shown in FIG. 1, the shallow grooves 4, 4... Are narrower than the fluid introduction groove 3 in a plan view, and a plurality of the shallow grooves 4 are formed with respect to one fluid introduction groove 3. The plurality of shallow grooves 4, 4... Have a grating structure formed in parallel with periodicity, and any of the shallow grooves 4 communicates with the fluid introduction groove 3. In the region where the shallow groove 4 is formed, there is a difference in the clearance between the sliding surfaces between the concave portion and the convex portion of the shallow groove 4, and a large fluid pressure is generated at the convex portion where the clearance is small. Since the load is supported by this fluid pressure, a fluid lubrication state with a low friction coefficient can be realized. In this embodiment, each of the plurality of shallow grooves 4 is arranged in a direction intersecting with the fluid introduction groove 3 at a predetermined angle, and each shallow groove 4 is connected to one edge of the fluid introduction groove 3 at its end. (See FIG. 2).

In this embodiment, the plurality of shallow grooves 4, 4... Have a linear shape and are arranged in the tangential direction. Groove depth of the shallow groove 4 Wb is viewpoint et achieving oil film formation of a highly rigid due to shallow grooves 4 when the oil film thickness is small, and a 1μm or less. More preferably, the groove depth Wb of the shallow groove 4 is set to 500 nm or less. Each of the shallow grooves 4, 4... Is arranged in a direction perpendicular to the fluid introduction groove 3, and as a result, in the tangential direction of the sliding direction (rotation direction) of the other flat surface 2 a (the mating member 2). . Moreover, all the shallow grooves 4, 4 ... arrange | positioned at the both sides of the fluid introduction groove | channel 3 arrange | positioned as mentioned above are formed in the same longitudinal dimension.

  Looking at the dimensional relationship between the fluid introduction groove 3 and the shallow groove 4, the groove depth Wa of the fluid introduction groove 3 is not particularly limited as long as lubricating oil can be supplied between the two opposing flat surfaces 1a and 2a. Is preferable. Further, as shown in FIG. 2, the relationship between the groove depth Wa of the fluid introduction groove 3 and the groove depth Wb of the shallow groove 4 is set such that Wa> Wb is always established. Specifically, the ratio of the groove depth Wa of the fluid introduction groove 3 to the shallow groove 4 groove depth Wb is 5 or more and 200 or less, more preferably 10 or more and 100 or less, and still more preferably 20 It is set to be 50 or less. Further, a fluid is generated so that a dynamic pressure effect of the lubricating oil sufficient to form an oil film can be generated between at least the region where the fluid introduction groove 3 is not formed in one plane 1a and the other plane 2a facing this region. It is also possible to determine the dimension of the introduction groove 3, and for example, it is preferable to determine in consideration of the weight (support load) of the mating member 2 and the sliding speed. Note that the dimensions of the shallow groove 4, especially the groove depth Wb, can be defined in relation to the roughness or flatness of one flat surface 1a on which the shallow grooves 4, 4,... Are formed. It is also possible to set the surface accuracy of the flat surface 1a and the groove depth Wb of the shallow groove 4 so that the surface roughness Ra or flatness thereof does not exceed the value of the groove depth Wb. This is to secure an oil film.

  A known groove forming means can be employed for the fluid introducing groove 3. Further, the means for forming the plurality of shallow grooves 4, 4... Is not particularly limited. However, when forming a groove having a groove depth of 1 μm or less as described above, the irradiation intensity is, for example, near the processing threshold. Effective is a means of forming a self-organized structure by irradiating a linearly polarized laser beam on one plane and scanning while overlapping the irradiated portions. According to this means, it is possible to form a plurality of shallow grooves 4, 4... With a period (pitch) and a depth equal to or less than the wavelength of incident light contained in the laser to be irradiated.

  Next, the operation of the plane sliding mechanism having the above configuration will be described. First, as shown in FIG. 2, when the sliding speed of the other opposing flat surface 2a (the mating member 2) is large, or when the load from the mating member 2 is small, the lubricating oil mainly from the fluid introduction groove 3 is used. As a result, an oil film having a relatively large film thickness is formed between the opposing flat surfaces 1a and 2a. In terms of the relationship with the groove depths Wa and Wb, an oil film having an oil film thickness Wc that is relatively closer to the groove depth Wa of the fluid introduction groove 3 than the groove depth Wb of the shallow groove 4 is formed. In this case, the hydraulic pressure rises at the edge portion on the front side in the sliding direction of the fluid introduction groove 3 (left edge portion in FIG. 2). In this case, the presence of the shallow grooves 4, 4... Connected to the fluid introduction groove 3 on the front side in the sliding direction widens the gap between the edge portion on the front side in the sliding direction of the fluid introduction groove 3 and the flat surface 2a. Therefore, the effect of reducing the dynamic pressure effect of the fluid introduction groove 3 is suppressed and the rapid increase of the oil film thickness is suppressed.

  In addition, as shown in FIG. 3, when the sliding speed of the other plane 2a is low, or when the load from the mating member 2 is large, the flow of lubricating oil from the fluid introduction groove 3 to the shallow groove 4 causes a shallow flow. A large dynamic pressure effect exceeding the dynamic pressure effect of the fluid introduction groove 3 is generated at the end of the groove 4 on the side away from the fluid introduction groove 3. Due to the dynamic pressure effect of the shallow groove 4 mainly, a highly rigid oil film having a relatively small film thickness is formed between the opposing flat surfaces 1a and 2a. In terms of the relationship with the groove depths Wa and Wb, an oil film having an oil film thickness Wc that is relatively closer to the groove depth Wb of the shallow groove 4 than the groove depth Wa of the fluid introduction groove 3 is formed.

  Further, the shape (dimensions) of the fluid introduction groove 3 and the plurality of shallow grooves 4, 4... And the arrangement mode thereof are arranged so that the dynamic pressure effect by the fluid introduction groove 3 and the plurality of shallow grooves 4, 4. By setting, when the oil film is relatively thick, the fluctuation of the oil film thickness is suppressed, in other words, the fluctuation of the flying height of the counterpart member 2 is suppressed, and high positional accuracy (parallel) is achieved with respect to the other plane 2a. Degree). In addition, when the oil film is relatively thin, high oil film rigidity can be exhibited while maintaining a required positional accuracy with respect to the other flat surface 2a.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to the above exemplary form, and it is needless to say that any form can be adopted within the scope of the present invention.

  For example, in the above embodiment, a case where a plurality of shallow grooves 4, 4... Intersecting with the fluid introduction groove 3 at a predetermined angle are arranged in a direction in which the longitudinal direction is a tangential direction of the rotation direction of the other plane 2a is described. However, it is of course possible to arrange them in other directions. FIG. 4 shows an example thereof, and shows a case where the fluid introduction groove 3 and a plurality of shallow grooves 4, 4... Communicating with the fluid introduction groove 3 are arranged in the circumferential direction of the plane 1a. Yes. That is, the shallow groove 4 has a gentle arc shape extending in the circumferential direction. Thus, the shallow groove 4 can take any angle as long as it is parallel to the sliding direction or inclined at an inclination angle of less than 90 °, in other words, as long as it is not orthogonal to the sliding direction. Further, it is not necessary that all the shallow grooves 4, 4... Connected to the fluid introduction groove 3 are aligned in the same direction, and the inclination angle of the shallow groove 4 is different between one side and the other side of the fluid introduction groove 3. The inclination angle may be different between the adjacent shallow grooves 4 and 4.

  Also, the longitudinal dimensions of the shallow grooves 4 do not necessarily have to be the same for all the shallow grooves 4, 4..., And may be appropriately varied according to the arrangement mode.

  The shape of the fluid introduction groove 3 is not necessarily limited to the illustrated embodiment. For example, as shown in FIG. 5, the fluid introduction groove 3 is formed in a trapezoidal shape whose width increases from the outer diameter edge 6 toward the inner diameter side. can do. That is, the fluid introduction groove 3 has an isosceles trapezoidal shape whose radial axis is the symmetry axis S. Note that it may be an isosceles trapezoid whose width decreases from the outer diameter edge 6 toward the inner diameter side. Moreover, as shown in FIG. 6, it is good also as a V-shape from which the width | variety becomes small toward the inner diameter side from the outer diameter edge 6. FIG.

  The fluid introduction groove 3 and the shallow groove 4 may be formed by any combination of one or more straight lines or curves.

  As shown in FIG. 7, the pair of fluid introduction grooves 3 a and 3 b are arranged so as to be line symmetric with respect to the radial axis as the symmetry axis S. In addition, the shallow groove 4a that communicates with one fluid introduction groove 3a and the shallow groove 4b that communicates with the other fluid introduction groove 3b are arranged to be a line object with respect to the symmetry axis S. In this way, the groove constituting body 5 is formed by the pair of fluid introduction grooves 3a and 3b and the pair of shallow grooves 4a and 4b.

  When the inner diameter side of the ring body is the high pressure side and the outer diameter side is the low pressure side, one end of the fluid introduction groove 3 opens to the inner diameter edge 7 of the plane 2 and the other end exists in the plane as shown in FIG. ing. Further, as shown in FIG. 9, the outer diameter side groove is formed by a first fluid introduction groove 3a having one end opened to the outer diameter edge 6 and the other end existing in a plane, and a first shallow groove 4a communicating with the first fluid introduction groove 3a. A structure 5a is formed. Also, an inner diameter side groove constituting body 5b is formed by the second fluid introduction groove 3b having one end opened to the inner diameter edge 7 and the other end existing in a plane and the second shallow groove 4 communicating with the second fluid introduction groove 3b. Thus, what provided the outer diameter side groove structure 5a and the inner diameter side groove structure 5b may be sufficient.

  Of course, other specific forms can be adopted for matters other than the above as long as the technical significance of the present invention is not lost.

  Hereinafter, an experiment for verifying the effectiveness of the planar sliding mechanism according to the present invention will be described.

  This experiment was conducted using a ring-on-disk test apparatus that can easily realize parallel sliding in order to prevent changes in lubrication characteristics due to the inclination of the test piece. A hardened material of SUS440C was used for the ring-shaped test piece on the rotating side. SiC was used for the disk-shaped test piece on the fixed side. The sliding plane of any test piece was set to have a surface roughness Ra of 0.02 μm or less and a flatness of 0.1 μm or less. All sliding planes of the disk-shaped test piece were mirror surfaces. For the ring-shaped test pieces (outer diameter: 16 mm, inner diameter: 10 mm), two types of sliding planes were prepared: (1) only the fluid introduction groove, and (2) the combination of the fluid introduction groove and the shallow groove. (1) is a comparative example, and (2) is an example. The fluid introduction groove is arranged in a direction extending in the radial direction of the ring-shaped plane, in other words, in a direction perpendicular to the sliding direction of the mating member (disk). Eight of these fluid introduction grooves are arranged at equal intervals in the circumferential direction. The width dimension of the fluid introduction groove was 200 μm, and the groove depth was 6 μm. The shallow grooves were arranged in parallel in a grid pattern at a pitch of about 700 nm on both side edges of the fluid introduction groove. The longitudinal dimension was set (about 400 μm) so that the shallow groove was disposed in a 1 mm wide region with the fluid introduction groove as the center. The depth of the shallow groove was 200 nm, and the arrangement direction was perpendicular to the fluid introduction groove. The plurality of shallow grooves are irradiated with a femtosecond laser having a wavelength of 800 nm and linearly polarized light on the sliding plane of the test piece with an irradiation intensity in the vicinity of the processing threshold, and scanning is performed while overlapping the irradiated portions. Formed. 400 mg of lubricating oil (viscosity grade: VG32) was previously supplied onto the sliding plane, and no oil was supplied during the experiment.

  In the ring-on-disk test, the load is fixed at a predetermined value, and after starting from a stationary state at a sliding speed of 1.2 m / s, the sliding speed is gradually reduced to 0.14 m / s every 5 minutes. The sliding torque at each stage was measured. The sliding speed was a value at the average diameter (13 mm) of the ring-shaped test piece. The dynamic friction coefficient was calculated from the measured sliding torque. The load was set in three stages of 9.0N, 30.0N, and 50.5N. The above test was performed on two types of test pieces: (1) only the fluid introduction groove, and (2) a combination of the fluid introduction groove and the shallow groove.

  The experimental results are described below. FIG. 10 shows the result of a sliding experiment in which the sliding plane is composed of only the fluid introduction groove (comparative example). The horizontal axis represents the sliding time [min], the left vertical axis represents the dynamic friction coefficient, and the right side The vertical axis represents the sliding speed [m / s]. A portion indicated by a broken line in the figure indicates a sliding speed, and a portion indicated by a solid line indicates a dynamic friction coefficient. FIG. 11 shows the result of a sliding experiment when the sliding plane is a combination of a fluid introduction groove and a shallow groove (Example). Items on the horizontal and vertical axes, and items indicated by various lines in the figure are the same as those in FIG. First, from the experimental results shown in FIG. 10, (1) only in the fluid introduction groove, a rapid increase in the coefficient of dynamic friction was observed at a predetermined sliding speed (0.35 m / s), and seizure occurred. On the other hand, as shown in FIG. 11, in the case of (2) the combination of the fluid introduction groove and the shallow groove, a state in which the dynamic friction coefficient was low was observed through all the measured sliding speed steps. This is considered to have been in a fluid lubrication state regardless of the sliding speed. (2) In the case of the combination of the fluid introduction groove and the shallow groove, as shown in FIG. 12, the fluid lubrication is maintained even when the load is increased to 30.0N and 50.5N, and the dynamic friction coefficient is increased as the load is increased. Declined.

  FIG. 13 is obtained from the experimental results shown in FIG. 12, and shows the change in the oil film thickness accompanying the change in the sliding speed in the case of the combination of the fluid introduction groove and the shallow groove (Example). Here, the vertical axis in FIG. 13 indicates the oil film thickness [μm], and the horizontal axis indicates the sliding speed [m / s]. The oil film thickness was calculated from the dynamic friction coefficient obtained in the previous sliding experiment and the viscosity of the used lubricating oil (this time, the viscosity value at room temperature was used). From the experimental results shown in FIG. 13, the oil film thickness does not vary so much with respect to the load variation. In particular, at low speed, the oil film thickness becomes submicron and the rigidity becomes very high, so that it can be seen that there is almost no change in the oil film thickness with respect to the load fluctuation. Good sealing performance is maintained when the oil film thickness is several μm or less. (2) When the fluid introduction groove and shallow groove are combined, both good sealing performance and fluid lubrication with low friction are achieved. You can see that

1a, 2a Plane 3 Fluid introduction groove 4 Shallow groove 5 Groove structure Wa Groove depth (fluid introduction groove)
Wb groove depth (shallow groove)
Wc Oil film thickness S Axis of symmetry

Claims (3)

A plane sliding mechanism that performs relative rotational sliding between opposing planes through a film of lubricating fluid and seals the inner diameter side and the outer diameter side,
One of the planes opens to one of the inner diameter side or the outer diameter side, and an end portion in the direction opposite to the radial direction of the opening exists in the plane, and the lubricating fluid from the opening side faces the surface. A fluid introduction groove to be introduced into a ring-shaped sliding portion between planes;
A plurality of shallow grooves that are shallower than the fluid introduction groove, communicate with the fluid introduction groove, and have a periodicity in a direction parallel to the sliding direction of the other flat surface or inclined at an inclination angle of less than 90 °. With grooves ,
The one fluid introduction groove and a plurality of shallow grooves communicating with the one fluid groove constitute a groove structure, and the groove structure is arranged in line symmetry with the radial axis as a symmetry axis.
The planar sliding mechanism in which the plurality of shallow grooves are formed at a pitch of 10 μm or less and are formed to a depth of 1 μm or less . The planar sliding mechanism according to claim 1, wherein the plurality of shallow grooves are arranged in a circumferential direction or a tangential direction of a rotation direction . The plurality of shallow grooves are formed in a self-organized manner by irradiating the one plane with a linearly polarized laser beam with an irradiation intensity in the vicinity of a processing threshold, and scanning while overlapping the irradiated portions. Item 3. A planar sliding mechanism according to item 1 or 2 .

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