JP2002286026A - Sliding bearing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new sliding bearing structure capable of improving longer life of the bearing by arranging a means to prevent foreign matters from mixing between sliding surfaces. SOLUTION: Supporting surface portions 121 and 122 having herring bone type groove structure are formed on an outer peripheral surface of a rotary side bearing body 120 fixed in a rotary shaft 110. Further, discharging surface portions 123 and 124 having spiral type groove structure are also formed at both end sides 120a and 120b, which are far from the supporting surface portions. Upon supporting the rotary shaft 110 in the inner part of a fixed side bearing body 130 by means of the supporting surface portions 121 and 122 and also upon preventing invasion of foreign matters by means of the discharging surface portions 123 and 124, defects of the bearing structure can be prevented, and longer life of the bearing structure can be expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding bearing structure, and more particularly to an improvement in a bearing structure operating as a dynamic pressure bearing.

[0002]

2. Description of the Related Art Generally, a sliding bearing having a bearing structure in which a pair of sliding surfaces are opposed to each other is known. This sliding bearing has the advantage of simple structure and easy downsizing. However, if foreign matter such as dust enters between the sliding surfaces, the torque loss increases, and galling or seizure occurs between the sliding surfaces. This causes a problem that sufficient durability cannot be obtained due to the occurrence of the problem.

[0003] As means for solving the problems caused by foreign substances entering between the sliding surfaces as described above, for example, JP-A-5-202936 and JP-A-7-121 are known.
There is a sliding bearing described in Japanese Patent No.

The sliding bearing described in Japanese Patent Application Laid-Open No. 5-202936 has a load portion and a non-load portion with respect to the rotating shaft in order to discharge foreign matter out of the bearing body while securing a sufficient oil film forming ability. Is formed, and a foreign matter discharge groove extending in the axial direction is provided in a non-load portion of the bearing body.

The sliding bearing described in Japanese Patent Application Laid-Open No. 7-12123 has a lubricating oil-containing lubricating composition formed at the end of the bearing in order to enhance abrasion resistance in an environment with many foreign substances. Is provided.

On the other hand, as a sliding bearing, there is a dynamic pressure bearing which has a pair of sliding surfaces opposed to each other via a fluid such as a lubricant and supports the bearing by a dynamic pressure effect of a fluid. It is known that a herringbone type groove structure is formed on the outer peripheral surface of the rotating shaft or the inner peripheral surface of the outer cylinder, and the bearing structure is obtained by holding the fluid pressure by the groove structure.

[0007]

However, in the sliding bearing described in the above-mentioned conventional Japanese Patent Application Laid-Open No. 5-202936, since the pressure of the lubricating fluid is not generated in the non-load portion where the foreign matter discharge groove is provided. However, there is a problem that only a load in a specific direction corresponding to the above-described load portion can be supported.

Further, in the sliding bearing described in the above-mentioned Japanese Patent Application Laid-Open No. 7-12123, since the lubricating oil gradually exudes from the seal using the lubricating oil-containing material, the lubricating effect of the seal can be reduced over time. It is difficult to maintain a good lubricating state for a long period of time, and there is a problem in durability such that the seal needs to be replaced.

Further, the above-mentioned hydrodynamic bearing is a sliding bearing capable of supporting a load from all directions around the axis and maintaining a good lubricating state for a long period of time. When mixed between the moving surfaces, the foreign matter tends to stay in the region where the fluid pressure is held by the dynamic pressure effect, so that there is a problem that the loss torque increases, and galling or seizure occurs in the region.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to extend the life of a bearing by providing means for preventing foreign matter from entering between sliding surfaces. It is to provide a new sliding bearing structure.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a sliding bearing structure according to the present invention is a sliding bearing structure having a pair of sliding surfaces opposed to each other with a fluid interposed therebetween. At least one of the surfaces is provided with a support surface portion having a groove structure for applying a holding pressure to the fluid, and at least one of the pair of sliding surfaces, the support surface portion more than the formation area of the support surface portion A discharge surface portion having a groove structure which is arranged on the edge side of the sliding surface and applies a discharge pressure toward the edge of the sliding surface to the fluid is provided.

According to the present invention, the bearing action can be ensured by the holding pressure generated at the support surface, and foreign matter such as dust moves to the formation area of the support surface by the discharge pressure generated at the discharge surface. Can be prevented, and the foreign matter can be discharged toward the edge of the sliding surface. Therefore, an increase in torque loss and occurrence of galling and seizure between the sliding surfaces can be reduced. The life of the structure can be extended. In particular, in a sliding bearing structure, a tilt occurs between the pair of sliding surfaces at the time of starting or stopping, and the tilt often causes the vicinity of the edges of the pair of sliding surfaces to contact each other. This is very effective in that the intrusion of dust generated by the above-mentioned contact can be prevented by the discharge pressure generated by the discharge surface portion, and the dust can be discharged.

Here, the sliding bearing structure of the present invention may be a journal bearing or a thrust bearing, and may have both functions of a journal bearing and a thrust bearing. Further, a support surface portion and a discharge surface portion may be formed on one of the pair of slide surfaces, or a support surface portion may be formed on one of the slide surfaces, and the other slide surface may be formed on the other slide surface. A discharge surface portion may be formed on the surface.
Further, the support surface portion or the discharge surface portion may be formed on both of the pair of sliding surfaces.

In the present invention, it is preferable that the discharge surface portion is formed on both sides of the support surface portion. Since the discharge surface portions are formed on both sides of the support surface portion, it is possible to obtain the effect of preventing foreign matter from entering and discharging foreign matter at any of both end edges of the pair of sliding surfaces.

In the present invention, preferably, the groove structure of the support surface portion is formed so that a plurality of support portions for generating the holding pressure are formed between both end edges of the pair of slide surfaces. According to this means, since the pair of sliding surfaces are supported by the fluid pressure at the plurality of support portions between the two ends of the pair of sliding surfaces, the stability of the supporting state can be improved.

In the present invention, it is preferable that the groove structure of the support surface is a herringbone type groove structure.
According to this means, by providing the herringbone type groove structure on the support surface portion, the fluid pressure can be smoothly and reliably generated and held.

In the present invention, it is preferable that the groove structure of the discharge surface is a spiral groove structure. According to this means, by providing the spiral groove structure on the discharge surface portion, the discharge pressure can be formed smoothly and reliably.

In the present invention, it is preferable that the depth of the groove structure of the discharge surface portion is deeper than the depth of the groove structure of the support surface portion. According to this means, by making the groove structure of the discharge surface portion deep, the effect of discharging foreign matter can be enhanced, and even if foreign matter enters the discharge surface portion, galling and seizure can be prevented. On the other hand, by forming the groove structure of the support surface portion relatively shallow, the fluid pressure does not easily decrease, and the lubricity of the fluid and the bearing accuracy can be improved.

More specifically, the groove depth of the support surface portion is equal to or smaller than the gap between the pair of sliding surfaces, and the groove depth of the discharge surface portion is smaller than the gap between the pair of sliding surfaces. Is also preferably large. This is because the above-described effect due to the groove depth in the support surface portion and the discharge surface portion is affected by the ratio between the fluid thickness between the sliding surfaces and the groove depth.

In the present invention, it is preferable that the fluid is supplied to a boundary region between the support surface and the discharge surface. According to this means, since the fluid is supplied to the boundary region between the support surface and the discharge surface, the fluid pressure in the region where the support surface is formed can be increased, and at the same time, the fluid slides from the discharge surface. Since the flow of the fluid to the edge of the surface can be created, the foreign matter can be more reliably discharged from the formation area of the discharge surface portion. Further, by forcibly supplying the fluid, poor lubrication such as oil film breakage is less likely to occur, and the lubricating state by the fluid can be made better and more stable.

In the present invention, it is preferable that the fluid is recovered from between the edges of the pair of sliding surfaces. According to this means, since the fluid is recovered from between the edges of the pair of sliding surfaces, the fluid supplied at the boundary region between the support surface portion and the discharge surface portion can be removed from the pair of sliding surfaces. Can always be collected from the edge of
The lubricating effect in the region where the support surface portion is formed and the effect of discharging foreign matter from the region where the discharge surface portion is formed can always be suitably obtained.

In the present invention, it is preferable that a fluid circulation path is provided for returning the fluid recovered from between the edges of the pair of sliding surfaces to a boundary region between the support surface portion and the discharge surface portion. According to this means, since the fluid can be circulated through the fluid circulation path, it is possible to configure a good bearing structure in a closed system. Here, it is preferable that foreign matter is removed from the collected fluid by a foreign matter removing means such as a filter, and then the fluid is returned to the boundary region.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sliding bearing structure according to an embodiment of the present invention.

[First Embodiment] FIG. 1 is a schematic sectional view showing a first embodiment of a sliding bearing structure 100 according to the present invention. The sliding bearing structure 100 includes a rotating shaft 110,
A rotating bearing (rotating body) fixed to the rotating shaft 110
120, and a fixed-side bearing body (outer cylinder) 130 that covers the rotating-side bearing body 120. Further, the rotation-side bearing body 120
And the fixed-side bearing body 130 are filled with a lubricating liquid 141 made of lubricating oil or the like.

The rotation-side bearing body 120 is formed in a cylindrical shape.
The rotating shaft 110 is press-fitted or inserted into the inside thereof and fixed to each other by a method such as adhesion. In addition,
The rotation shaft 110 and the rotation-side bearing body 120 may be formed integrally.

A pair of support surfaces 12 each having a herringbone type groove structure are provided on the outer peripheral surface of the rotation side bearing body 120.
1, 122 are formed so as to be arranged in the axial direction. The herringbone type groove structure of the support surface portions 121 and 122 is such that when the rotation shaft 110 is rotated in the direction of arrow R in the drawing, the central portion 12 of the support surface portions 121 and 122 in the axial direction is rotated.
A holding pressure for holding the lubricating liquid 141 is generated near 1a and 122a, and the fluid pressure in this portion is higher than that in the surroundings.

On the other hand, on both sides in the axial direction of the support surface portions 121 and 122, discharge surface portions 123 and 124 each having a spiral groove structure are formed. These discharge surfaces 1
The groove structures 23 and 124 discharge the lubricating liquid 141 from the discharge surface portions 123 and 124 toward the edges 120a and 120b of the rotating bearing body 120 when the rotating shaft 110 is rotated in the direction of the arrow R. Is configured to generate a discharge pressure.

FIG. 2 shows the pressure distribution of the lubricating liquid 141 in the sliding bearing structure 100. Support surface 1
21 and 122, the central portions 121a,
While a large pressure is generated at 122a, the boundary region between the support surface portions 121 and 122 and the support surface portions 121 and
Negative pressure is generated in the boundary region between the discharge surface portion 22 and the discharge surface portions 123 and 124. Also, the discharge surfaces 123, 12
4 has a maximum negative pressure in the boundary region with the supporting surface portions 121 and 122, and the edge 12
The pressure gradually increases toward 0a and 120b.

FIGS. 3A and 3B are enlarged sectional views (a) and (b) of the groove structure of the support surface portions 121 and 122 and the groove structure of the discharge surface portions 123 and 124. Here, the support surface 12
1,122 herringbone-shaped grooves 121b, 122b
The depth D1 is shallow, and the depth D2 of the spiral grooves 123b and 124b of the discharge surface portions 123 and 124 is formed deep. This is because the grooves 121b and 122b are
In order to maintain the fluid pressure at 21 and 122 and not to reduce the lubricating fluid pressure and to ensure lubricity and bearing accuracy, it is necessary to make it shallow to some extent, but on the other hand, the grooves 123b, 1
This is because 24b needs to be formed to a certain depth in order to enhance the discharge effect of the discharge surface portions 123 and 124 and to make it difficult to receive damage such as galling due to foreign matter.

In the case of the present embodiment, the gap between the outer peripheral surface of the rotating bearing 120 and the inner peripheral surface of the fixed bearing 130 is set to about 5 μm.
m, the depth D1 is about 0.003 to 0.0
1 mm and the depth D2 are preferably about 0.1 to 0.5 mm. In this case, the diameter of the bearing surface of the journal bearing (the outer diameter of the rotation-side bearing body 120 or the inner diameter of the fixed-side bearing body 130, or an average thereof) is about 8 mm.

In general, the groove depth of the support surface is equal to or smaller than the gap between the rotating side sliding surface and the fixed side sliding surface, and the groove depth of the discharge surface is the rotating side sliding surface. Preferably, it is larger than the gap between the sliding surface and the stationary sliding surface.

When the depth D1 exceeds the above range, the lubricating fluid cannot be sufficiently maintained due to the leakage of the lubricating fluid, and as a result, the bearing accuracy also decreases. When the depth D1 is less than the above range, the holding pressure forming ability by the groove is reduced, so that the pressure of the lubricant cannot be sufficiently obtained. Further, if the depth D2 exceeds the above range, it is impossible to sufficiently obtain a discharge pressure gradient of the lubricating liquid due to leakage of the lubricating liquid, and if the depth D2 is less than the above range, the discharge pressure is formed by the groove. As ability decreases,
Again, it is difficult to obtain a sufficient gradient of the lubricating fluid discharge pressure.

In the present embodiment, the support surfaces 121,
The rotary shaft 110 is supported by the lubricating liquid holding pressure distribution formed as shown in FIG. In particular, two support portions (portions corresponding to the central portions 121a and 122a) provided by the two support surface portions 121 and 122.
, Stable bearing characteristics can be obtained. In addition, since the discharge surface portions 123 and 124 are formed on both sides of the support surface portions 121 and 122, foreign matter such as dust can be removed from the outer peripheral surface of the rotating bearing member 120 and the inner peripheral surface of the fixed bearing member 130 from outside. Even if it tries to intrude in between, it is stopped, so the loss torque increases due to the entry of foreign matter,
Prevents galling and burning.

In particular, as shown in FIG. 4, when the rotating operation of the rotating shaft 110 is started or stopped, the dynamic pressure effect is reduced and the rotating shaft 110 may be inclined. Of the fixed bearing 1
30 may come into contact with the inner peripheral surface, and dust may be generated at the contact portion. However, in the present embodiment, as described above, the discharge surface portion 12 is provided on the edge 120a, 120b side.
Since 3, 124 are formed, it is possible to prevent the dust from entering the support surface. Such dust is generally discharged to the outside by the spiral groove structure of the discharge surfaces 123 and 124.

[Second Embodiment] Next, a second embodiment according to the present invention will be described.
A sliding bearing structure 100 'of the embodiment will be described with reference to FIG. In this embodiment, the same parts as those of the slide bearing structure 100 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. This sliding bearing structure 10
0 ′ differs from the first embodiment in that the supply units 131 and 132 for supplying the lubricant 141 are provided on the fixed bearing 130. The supply section 131 has a supply port for the lubricant 141 at a position of the fixed-side bearing body 130 corresponding to the boundary area C1 between the support surface section 121 and the discharge surface section 123. A lubricant 141 supply port is provided at a portion of the fixed-side bearing body 130 corresponding to a boundary region C2 between the surface portion 124 and the surface portion 124. Also,
It is preferable that a plurality of the supply units 131 and 132 (or their supply ports) are respectively dispersedly formed around the axis of the bearing structure.

In this embodiment, the boundary area C
Since the lubricant 141 is supplied from 1 and C2, the pressure distribution of the lubricant 141 is raised as a whole in accordance with the supply pressure. Boundary region C1,
C2 is a negative pressure in the first embodiment as shown in FIG. 2, but by introducing the lubricant 141 here, the holding pressure of the fluid in the region where the support surface portions 121 and 122 are formed is further increased. be able to. In addition, the boundary area C1,
The lubricant 141 can flow from C2 toward the bearing edge. The lubricant 141 flowing in this way flows out from the edges 120a and 120b of the rotation-side bearing body 120 to the outside. Due to the presence of this flow, the discharge surfaces 123 and 124
The dust generated in the formation region can be swept out to the outside, and the entry of foreign matter such as dust from the outside can be more reliably prevented.

FIG. 6 shows a plain bearing structure 10 according to this embodiment.
Fluid supply means 14 for supplying lubricant 141 to 0 '
FIG. 2 is a schematic explanatory diagram showing a configuration of a zero. This fluid supply means 1
Reference numeral 40 denotes a liquid reservoir 142 for storing the lubricant 141, and a liquid supply pump 143 for sending the lubricant 141 from the liquid reservoir 142 to the supply units 131 and 132 of the sliding bearing structure 100 '.
And a collecting pipe 144 for collecting the lubricant 141 discharged from the bearing edge in the sliding bearing structure 100 ′.
145 and a foreign matter separating means (filtration filter) 1 for filtering the lubricant 141 collected by the collecting pipes 144 and 145 and removing foreign matter mixed in the lubricant 141.
46. The lubricant 141 that has passed through the foreign matter removing means 146 is returned to the liquid reservoir 142. The fluid supply means 140 is provided with the lubricating liquid 14 as a whole as described above.
1 is configured to circulate the fluid.

Third Embodiment Next, a third embodiment according to the present invention will be described.
A slide bearing structure 200 according to the embodiment will be described with reference to FIG. The sliding bearing structure 200 includes a rotating shaft 210
A rotation-side bearing body 220 having a cylindrical portion on one end side and a disc-shaped portion on the other end side; and a cylindrical portion 231 on one end side like the rotation-side bearing body 220, Disc shaped part 23
2 having a fixed side bearing body 230.

The rotating bearing 220 has a support surface 2 having a herringbone type groove structure similar to that of each of the above embodiments.
21 and 222 and the edge 220 a viewed from the support surface portion 221.
A discharge surface portion 223 having a spiral groove structure similar to that of each of the above embodiments provided on the side is formed on the outer peripheral surface of the cylindrical portion. Further, a discharge surface portion 224 having a spiral groove structure on the surface of the disc-shaped portion is formed on the edge 220b side as viewed from the support surface portion 222.

In this sliding bearing structure 200, the rotating side bearing body 220 and the fixed side bearing body 230 are inserted and fitted, and a lubricant (not shown) is filled between the opposing surfaces of the rotating side bearing body 220 and the fixed side bearing body 230, so that the rotating side bearing body 230 is filled. The cylindrical part of the body 220 and the cylindrical part 231 of the fixed-side bearing 230 function as a journal bearing (radial bearing), and the disk-shaped part of the rotating-side bearing 220 and the disk of the fixed-side bearing 230 The shape portion 232 is configured to function as a thrust bearing portion.

In this case, the discharge surface portion 224 provided on the surface of the disk-shaped portion of the rotation-side bearing body 220 faces the surface of the disk-shaped portion 232, and rotates the rotation-side bearing body 220 in the direction of arrow R in the figure. Thus, similarly to the discharge surface portion 223 on the opposite side, a discharge pressure toward the edge 220b (outer edge of the disk-shaped portion) is generated for the lubricating liquid (not shown).

[Fourth Embodiment] Next, a plain bearing structure 300 according to a fourth embodiment of the present invention will be described with reference to FIG. The sliding bearing structure 300 has a disk-shaped rotating side bearing body 320 and a disk-shaped fixed side bearing body 330, such that the surfaces of both are opposed to each other via a lubricant (not shown). It is formed. This sliding bearing structure 300 constitutes a thrust bearing.

The rotation side bearing body 320 has a center hole 320A.
Are formed, and an edge 3 which is an opening edge of the center hole 320A is formed.
20a and an edge 320b which is an outer edge portion are provided. A ring-shaped support surface portion 321 is formed on the surface between both end edges 320a and 320b, and discharge surface portions 322 and 323 are formed on both inside and outside of the support surface portion 321. The support surface portion 321 has a herringbone-type groove structure that applies a holding pressure to the lubricant when the rotation-side bearing body 320 is rotated in the direction of arrow R in the drawing. In addition, the rotation side bearing body 330 is provided on the discharge surface portions 322 and 323.
Is rotated in the direction of arrow R in the drawing to form a spiral groove structure that applies a discharge pressure toward the edges 320a and 320b to the lubricant.

On the other hand, the fixed side bearing body 330 has a center hole 330A formed at a position substantially corresponding to the center hole 320A of the rotating side bearing body 320. Also, the center hole 330
A and a plurality of openings 330B, 330C
Are formed. The opening 330 </ b> B
An opening 330C is open in a boundary region between the support surface portion 321 and the discharge surface portion 323 of the rotation-side bearing body 330.

This embodiment is different from the above embodiments in that it has a thrust bearing structure for supporting on a surface orthogonal to the rotating shaft. 321 and discharge surface portions 322, 3
The same effects as those of the above-described embodiments can be achieved by the use of 23.

Further, by supplying a lubricant (not shown) through the openings 330B and 330C in the same manner as in the second embodiment, the lubricant is supplied to the support surface 321 and the discharge surface 32.
2 and 323, the supporting surface 3
The support pressure in the formation area of the discharge nozzle 21 can be increased, and the ability to discharge foreign substances in the formation area of the discharge surface portions 322 and 323 can be increased. Here, the lubricating liquid is collected from the edges 320a and 320b. in this case,
In the present embodiment, the same fluid supply means as that shown in FIG. 6 can be provided.

It should be noted that the sliding bearing structure of the present invention is not limited to the above-described illustrated example, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, in each of the above embodiments, the support surface portion and the discharge surface portion are formed on the rotating-side bearing body, but the support surface portion and the discharge surface portion may be formed on the fixed-side bearing body. Also,
Either the supporting surface portion or the discharging surface portion is formed on one of the rotating side bearing member and the fixed side bearing member, and the supporting surface portion and the discharging surface portion are formed on the other of the rotating side bearing member and the fixed side bearing body. May be formed.

[0048]

As described above, according to the present invention,
It is possible to prevent an increase in torque loss due to entry of foreign matter, or to prevent galling and seizure, and to extend the life of the bearing.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing the structure of a first embodiment of a sliding bearing structure according to the present invention in a partial cross section.

FIG. 2 is an explanatory diagram showing a relationship between a structure and a pressure distribution of a lubricant in the first embodiment.

FIG. 3 is an enlarged cross-sectional view illustrating a groove structure of the rotation-side bearing body according to the first embodiment.

FIG. 4 is an explanatory view showing an inclined state of a rotation-side bearing body in the first embodiment.

FIG. 5 is a schematic perspective view showing the relationship between the structure of the second embodiment of the sliding bearing structure according to the present invention and the pressure distribution of the lubricant.

FIG. 6 is a schematic configuration diagram illustrating a schematic configuration of a lubricant supply unit according to a second embodiment.

FIG. 7 is a schematic perspective view showing the structure of a third embodiment of the sliding bearing structure according to the present invention.

FIG. 8 is a schematic perspective view showing the structure of a fourth embodiment of the sliding bearing structure according to the present invention.

[Explanation of symbols]

100, 100 ', 200, 300 Plain bearing structure 110, 210 Rotation shaft 120, 220, 320 Rotation side bearing body 120a, 120b, 220a, 220b, 320a,
320b Edge 121,122,221,222,321 Supporting surface part 123,124,223,224,322,323 Discharge surface part 130,230,330 Fixed side bearing body 140 Fluid supply means 141 Lubricant

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinozaki S. Junichiro 3-3-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (Reference) 3J011 AA07 AA20 BA02 BA06 BA08 CA03 JA02 KA02 KA03 KA04 LA05 MA07 MA08 MA26 MA27 PA02

Claims (9)

[Claims] 1. A sliding bearing structure having a pair of sliding surfaces facing each other via a fluid, wherein a groove structure for applying a holding pressure to the fluid is provided on at least one of the pair of sliding surfaces. A support surface portion having the following. An end portion of the slide surface is disposed on at least one of the pair of slide surfaces, closer to an edge of the slide surface than an area where the support surface portion is formed. A sliding bearing structure provided with a discharge surface portion having a groove structure for applying discharge pressure toward an edge. 2. The sliding bearing structure according to claim 1, wherein said discharge surface portion is formed on both sides of said support surface portion. 3. The groove structure of the support surface portion is formed such that a plurality of support portions for generating the holding pressure are formed between both end edges of the pair of slide surfaces. The sliding bearing structure according to claim 1 or 2. 4. The sliding bearing structure according to claim 1, wherein the groove structure of the support surface portion is a herringbone type groove structure. 5. The groove structure of the discharge surface portion is a spiral groove structure.
The sliding bearing structure according to any one of the above. 6. The sliding bearing structure according to claim 1, wherein a depth of the groove structure of the discharge surface portion is deeper than a depth of the groove structure of the support surface portion. . 7. The slide bearing according to claim 1, wherein the fluid is supplied to a boundary region between the support surface portion and the discharge surface portion. Construction. 8. The sliding bearing structure according to claim 7, wherein the fluid is recovered from between the edges of the pair of sliding surfaces. 9. The apparatus according to claim 8, further comprising a fluid circulation path for returning the fluid collected from between the edges of the pair of sliding surfaces to a boundary region between the support surface and the discharge surface. Sliding bearing structure.