JP2009097598A - Sliding bearing and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding bearing having superior sliding performance and abrasion resistance even at either load of a high load and a low load. <P>SOLUTION: In this substantially cylindrical sliding bearing, a resin part 3 is partially formed at the inner periphery of a bearing body 2 formed of sintered metal. A first bearing surface 4 formed of the sintered metal is formed at the inner periphery of the bearing body 2, and a second bearing surface 5 having a diameter smaller than that of the first bearing surface 4 is formed in the resin part 3. The sliding bearing is also constituted so as to have a state of supporting a radial load by the second bearing surface 5 and a state of supporting the radial load by the first bearing surface according to the radial load from a shaft 8 inserted into its inner periphery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sliding bearing and a manufacturing method thereof.

  As the sliding bearing, in addition to a sliding surface formed of a metal, a sliding bearing formed of a resin film is known. Sliding bearings with resin sliding surfaces can be manufactured at a lower cost than metal sliding bearings and are less likely to wear mating materials such as shafts. ing.

In addition, sliding bearings made of resin can be modified on the sliding surface in accordance with the application and purpose. There are known ones that have improved slidability or that have improved wear resistance by incorporating a reinforcing material such as glass fiber or carbon fiber (for example, see Patent Document 1).
JP 20061944397 A

  However, the above-described sliding bearing cannot be denied that the sliding surface is formed of a resin material, so that the strength and durability are inferior to those of a metal material. Therefore, the present situation is that it is not suitable for use under the same conditions, such as wear resistance being reduced under a high load and the resin film being easily peeled off.

  In particular, if this type of bearing is used for applications where the radial load received from the shaft during operation varies, or if the radial load suddenly increases for some reason such as vibration or impact, the above-mentioned plain bearings will provide sufficient bearing performance. It is difficult to demonstrate.

  In other words, while durability is required under high loads, slidability (low friction characteristics) tends to be emphasized rather than assuming high speed rotation under low loads. In addition, different material compositions are required. Therefore, it is difficult for existing plain bearings to satisfy the required characteristics at both high and low loads.

  In view of the above circumstances, an object of the present invention is to provide a sliding bearing having excellent slidability and wear resistance under both high and low loads.

  In order to solve the above problems, the present invention is a sliding bearing having a first bearing surface and a second bearing surface on the inner periphery of a metal bearing body, and the first bearing surface is constituted by the inner periphery surface of the bearing body. The second bearing surface is constituted by the surface of the resin portion provided on the inner periphery of the bearing body, and the second bearing surface is formed to have a smaller diameter than the first bearing surface, and is formed on the inner periphery of the bearing body. Provided is a slide bearing having a state in which a radial load is supported by a second bearing surface and a state in which the radial load is supported by a first bearing surface in accordance with a radial load from the inserted shaft.

  According to the slide bearing having the above configuration, the shaft is preferentially in sliding contact with the second bearing surface made of a resin having a relatively small diameter. Therefore, the radial load is compared with the state in which the radial load is supported on the second bearing surface. It occurs when it is small. Further, the resin portion that is relatively easily deformed by the radial load from the shaft is compressed and deformed in the direction in which the diameter of the second bearing surface is expanded, so that the radial load is supported by the metal first bearing surface. For this reason, the state of support by the first bearing surface occurs when the radial load is relatively large. Accordingly, the resin bearing surface can be formed with a composition suitable for a low load, and the metal bearing surface can be formed with a composition suitable for a high load. From the above, it is possible to provide a sliding bearing having excellent slidability and wear resistance even under high load or low load.

  Here, as a resin part which has a 2nd bearing surface, the film-like thing coat | covered and formed with resin on the internal peripheral surface of a bearing main body can be considered, for example. Alternatively, a concavity formed on the inner periphery of the bearing body and filled in the concavity can be considered.

  By filling and forming the resin portion in the concave portion as described above, the resin portion having the second bearing surface has a depth corresponding to the depth of the concave portion in addition to the thickness corresponding to the inner diameter dimensional difference between the second bearing surface and the first bearing surface. The thickness can be increased. Therefore, even if the load is the same, the compression amount of the resin portion, in other words, the diameter expansion amount of the second bearing surface can be increased. Therefore, it is possible to adjust the presence or absence of sliding contact with the first bearing surface by changing the depth of the recess. Can be changed.

  Various resins can be used for the resin forming the second bearing surface as long as they have slidability. However, considering further lubricity, low torque, etc. For example, a resin containing a lubricating component is preferable. Specifically, a solid lubricant or lubricating oil can be blended with the resin material as the base material. Alternatively, a resin having a porous structure such as foamed resin, a resin excellent in affinity with a lubricating oil, or a resin blended with a filler having a porous structure such as porous silica may be employed.

  As for the recess, it is preferable that the shape is a groove shape, and the groove-shaped recess extends to at least one end surface of the bearing body. If it is a bearing main body provided with the recessed part extended to one end surface, since the gate position at the time of injection molding can be arrange | positioned at the one end side of a bearing main body, it is easy to shape | mold. Further, when the resin part is injection-molded in each of the plurality of recesses, it can be said that it is a preferable mode because a mode in which the molten resin is supplied from the gate provided on one end side to each recess can be adopted.

  In the sliding bearing having the above-described configuration, for example, a bearing body having a first bearing surface and a concave portion on the inner periphery is formed of sintered metal, and then a resin portion is injection-molded in the concave portion to form a second bearing surface in the resin portion. Can be manufactured. If the bearing body is made of sintered metal in this way, the resin part and the bearing body are solidified in a state where the molten resin flows into the interior through a large number of openings formed in the surface of the recess during injection molding. A high fixing force can be obtained.

  Moreover, when forming a bearing main body with a sintered metal, after sizing a 1st bearing surface, a resin part can also be injection-molded to a recessed part. Alternatively, it is also possible to take a procedure of sizing the first bearing surface made of sintered metal and the surface of the resin portion to be the second bearing surface after the resin portion is injection-molded in the recess.

  Injection molding is performed in a state where the first bearing surface and the molding die are brought into close contact with each other by injection molding the resin portion using the bearing body having the first bearing surface sized in advance as an insert part. Accordingly, it is possible to avoid the situation where the molten resin flows into the gap between the first bearing surface and the molding die, and to accurately mold the resin portion. In addition, if both bearing surfaces are sized after injection molding of the resin part in the recess, the shape accuracy of the resin part caused by shrinkage during molding can be corrected by sizing. The shape of the bearing surface, particularly the inner diameter of the bearing surface can be adjusted. Even when sizing is performed before molding of the resin portion, it is preferable that the concave portion is not sized. This is because the anchor effect due to the resin flowing into the surface openings of the recesses is reliably obtained.

  As described above, according to the present invention, it is possible to provide a slide bearing having excellent slidability and wear resistance under both high and low loads.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a longitudinal sectional view of a plain bearing 1 according to an embodiment of the present invention. A sliding bearing 1 in FIG. 1 has a substantially cylindrical shape, and includes a bearing body 2 formed of sintered metal and a resin portion 3 partially provided on the inner periphery of the bearing body 2. Although not shown in the drawings, the inner periphery of the bearing body 2 is formed with a sintered metal first bearing surface 4 that slides on the outer peripheral surface of the shaft to be supported, and has a smaller diameter than the first bearing surface 4. A second bearing surface 5 is formed on the resin portion 3.

  FIG. 2 shows a cross-sectional view of the plain bearing 1 shown in FIG. As shown in the drawing, a plurality of groove-like recesses 6 extending in the axial direction are formed on the inner periphery of the bearing body 2, and the resin portions 3 are filled in the plurality of recesses 6. Therefore, in this embodiment, the 1st bearing surface 4 made from a sintered metal is arrange | positioned in the inner periphery of the bearing main body 2 in the state parted by the 2nd bearing surface 5 made from resin.

  FIG. 3 shows an enlarged cross-sectional view of the periphery of the recess 6 of the plain bearing 1 shown in FIG. In this embodiment, since the bearing body 2 is formed of a sintered metal, a large number of openings exist on the surface of the recess 6 (here, the inner surfaces 6a and 6a and the bottom surface 6b), and this surface is a surface. It has roughness on the order of roughness. On the other hand, the 1st bearing surface 4 adjacent to the recessed part 6 is smooth compared with the surface of the recessed part 6, and the ratio of surface opening is also small.

  The shaft 8 is supported by at least one of the first bearing surface 4 and the second bearing surface 5 of the sliding bearing 1 by inserting and rotating the shaft 8 on the inner periphery of the sliding bearing 1 having the above configuration. Here, FIG. 4A shows a state in which the radial load from the shaft 8 is supported by the second bearing surface 5 formed on the resin portion 3. FIG. 4B shows a state in which the radial load from the shaft 8 is supported by the first bearing surface 4 formed on the sintered metal bearing body 2. Hereinafter, both supporting states will be described in detail.

  When the radial load from the shaft 8 is relatively small, the outer peripheral surface 8a of the shaft 8 is preferentially slidably contacted with the second bearing surface 5 having a relatively small diameter, so that the shaft 8 is supported only by the second bearing surface 5. Rotation supported. On the other hand, when the radial load from the shaft 8 is large, the resin portion 3 that is relatively easily deformed is radially compressed by receiving the radial load from the shaft 8 and formed inside the resin portion 3. The second bearing surface 5 is displaced (expanded) to the outer diameter side. When the radial load reaches a predetermined value, the outer peripheral surface 8a of the shaft 8 in a state where the second bearing surface 5 is expanded is started to contact the first bearing surface 4. As described above, according to the radial load from the shaft 8, in other words, according to the diameter expansion amount of the second bearing surface 5, the radial load is supported by the second bearing surface 5 and the radial load by the first bearing surface 4. Is appropriately selected and realized.

  At this time, the bearing body 2 and the resin portion 3 are designed so that the above-described support state is achieved. Specifically, the inner diameter dimensional difference between the first bearing surface 4 and the second bearing surface 5 (in this illustrated example, the minimum inscribed circle radius of the second bearing surface 5 having a convex curved surface shape and the first bearing surface 4), the depth of the recess 6 (for example, about 0.2 mm), the thickness in the radial direction of the resin portion 3 determined from these, or between the adjacent resin portions 3 (second bearing surfaces 5). The above support state is realized by setting the circumferential interval, the material composition (rigidity) of the resin portion 3 and the like according to the magnitude of the radial load assumed in advance and the outer diameter of the shaft.

At this time, considering the expansion / contraction of both the resin portion 3 and the bearing body 2 within the assumed temperature range, the thickness of the resin portion 3 and the thickness of the portion where the recess 6 of the bearing body 2 is formed, etc. Can also be set. Specifically, {resin material linear expansion coefficient (unit: ° C.- ¹ )} × {radial thickness of resin part 3 (unit: μm)} in the resin part 3 is 0.15 or less. The amount of expansion in the radial direction of the resin portion 3 and the amount of diameter expansion of the concave portion 6 are substantially balanced by being preferably 0.13 or less, and more preferably 0.10 or less. As a result, the dimensional change due to the temperature change of the second bearing surface 5 provided on the inner side of the resin portion 3 can be suppressed to be small, and high bearing accuracy can be maintained.

  The slide bearing 1 having the above-described configuration includes, for example, a step of compacting metal powder as a raw material, a step of sintering a compacted body, a step of sizing the sintered body, and injecting a resin portion 3 into the sintered body. It can manufacture by passing through the process to shape | mold. Under the present circumstances, the recessed part 6 for injection-molding the resin part 3 can be formed at the time of compacting, for example.

  For compacting, for example, a Cu-based, Fe-based, or Cu-Fe-based metal powder can be used as a raw material powder. In consideration of the oil resistance of the resin part 3, when the bearing body 2 is used without impregnating the lubricating oil, the raw material is a powdered solid lubricant such as graphite or molybdenum disulfide mixed in a metal powder. It can also be used as a powder. Of course, if the resin portion 3 is formed of a material having sufficient oil resistance, the first bearing surface 4 can be obtained by impregnating the lubricating oil into the bearing body 2 without blending a solid lubricant. The lubricity can be ensured.

  Moreover, various resin materials can be used for the resin part 3, and the material especially excellent in slidability can be used suitably. It is also possible to mix a solid lubricant or lubricating oil. Specifically, polyethylene resins such as low density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, modified polyethylene resins, water-crosslinked polyolefin resins, polyamide resins, polystyrene resins, polypropylene resins, urethane resins, chlorotrifluoroethylene resins, tetra Fluoroethylene / hexafluoropropylene copolymer resin, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, vinylidene fluoride resin, ethylene / tetrafluoroethylene copolymer resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin , Polyphenylene ether resin, polycarbonate resin, aliphatic polyketone resin, polyphenylene sulfide resin, polyether sulfone resin, It can be exemplified polyetherimide resins, polyamideimide resins, polyether ether ketone resin, thermoplastic polyimide resin. Also, a mixture of two or more materials selected from the above resin materials, that is, a polymer alloy or the like can be used.

  Of the resin materials exemplified above, a polyethylene resin is very preferable from the viewpoint of low friction, and a polyethylene resin containing an ultrahigh molecular weight component is very preferable from the viewpoint of wear resistance.

  Also, solid lubricants that can be blended with the above resin materials include general solid lubricants such as polytetrafluoroethylene, graphite, molybdenum disulfide, boron nitride, tungsten disulfide, spindle oil, refrigerator oil, turbine oil, machine Oils, mineral oils such as dynamo oil, hydrocarbon oils, ester oils, polyglycol oils, silicone oils, synthetic oils such as fluorinated oils, and oils such as commonly used lubricating oils. Further, by impregnating the bearing body 2 made of sintered metal with these oils, it is possible to improve the lubricity of the first bearing surface. Impregnation can be performed by a method such as vacuum impregnation.

  In addition, an appropriate filler can be added to the resin material in order to improve the friction / wear characteristics and reduce the linear expansion coefficient. Specifically, glass fiber, carbon fiber, pitch carbon fiber, polyacrylonitrile (PAN) carbon fiber, aramid fiber, alumina fiber, polyester fiber, boron fiber, silicon carbide fiber, boron nitride fiber, silicon nitride fiber , Fibers such as metal fibers, asbestos, quartz wool, etc., and those knitted into cloth, minerals such as calcium carbonate, talc, silica, clay, mica, inorganic whiskers such as aluminum borate whisker and potassium titanate whisker Various heat resistant resins such as carbon black, graphite, polyimide resin and polybenzimidazole can be added. Furthermore, carbon fiber, metal fiber, graphite powder, zinc oxide and the like can be added for the purpose of improving thermal conductivity. Carbonates such as lithium carbonate and calcium carbonate, phosphates such as lithium phosphate and calcium phosphate, and the like can also be blended.

  In addition, the additive which can be widely applied to general synthetic resin with the compounding quantity which does not inhibit the effect of this invention can also be mix | blended together. For example, industrial additives such as mold release agents, flame retardants, antistatic agents, weather resistance improvers, antioxidants, and colorants may be added as appropriate, and the method of adding them is not particularly limited. .

  Furthermore, as long as the lubricity of the second bearing surface 5 can be ensured, modification for property improvement by chemical or physical treatment such as annealing treatment is possible at the intermediate product or final product stage.

  When the bearing body 2 is formed of sintered metal, the bearing body 2 can be used by impregnating the bearing body 2 with a liquid lubricant such as lubricating oil. At this time, the resin portion 3 is porous to communicate with the inside by foaming. Resin with a good quality structure, resin with excellent affinity with lubricating oil, solidified in a mixed state of lubricating oil to retain the lubricating oil between molecules, and gradually gave the physical properties that the lubricating oil oozes A resin, a resin mixed with a filler having a porous structure, or the like can be employed.

  As a resin blended with the filler having the above porous structure, there is a resin blended with a filler having communication holes in a resin material as a base material, specifically, a porous powder such as porous silica, etc. Can do. Preferable porous silica is a powder mainly composed of amorphous silicon dioxide. For example, an alkali silicate aqueous solution containing an alkali metal salt or an alkaline earth metal salt disclosed in JP 2000-143228 A, an aggregate of fine particles having a primary particle size of 15 nm or more, and organic Examples thereof include true spherical porous silica which is an aggregate of primary fine particles having a particle diameter of 3 to 8 nm obtained by emulsification in a solvent and gelation with carbon dioxide.

In the present invention, porous silica in which primary fine particles having a particle diameter of 3 to 8 nm are aggregated to form true spherical silica particles has communication holes, and thus is particularly preferable. Since porous silica having communication holes acts as a conduction path for the lubricating oil within the resin, it can provide extremely superior friction properties (small dynamic friction coefficient) compared to other means containing lubricating components. In addition, the lubricating oil oozes out to the bearing surface. The average particle size of the true spherical silica particles is preferably 0.5 to 100 μm, and particularly preferably 1 to 20 μm in view of easy handling and imparting sliding properties.

  Examples of such spherical porous silica include Asahi Glass Co., Ltd .; Sunsphere, Suzuki Oil & Fats Co., Ltd .; God Ball, and the like. In addition, examples of the porous bulk silica include Tokai Chemical Industries, Ltd .; Microid and the like.

True spherical silica particles in which primary fine particles having a particle diameter of 3 to 8 nm are aggregated have a specific surface area of 200 to
900m ² / g, preferably 300~800m ² / g, a pore volume of 1~3.5ml / g, pore size 5 to 30 nm, preferably 20 to 30 nm, an oil absorption of 150~400ml / 100g, preferably It preferably has a characteristic of 300 to 400 ml / 100 g. Moreover, even if it dries again after being immersed in water, it is preferable that the said pore volume and oil absorption amount maintain 90% or more before immersion. The specific surface area and the pore volume are values measured by a nitrogen adsorption method, and the oil absorption is a value measured according to JIS K 5101.

  As the spherical silica particles, those in which the inside and the outer surface are covered with silanol (Si—OH) are preferable. This is because the lubricant can be easily held inside. Furthermore, this type of porous silica can be subjected to an organic or inorganic surface treatment suitable for the base material. The shape of the particles is not particularly limited, and even non-spherical porous silica can be used as long as the average particle diameter, specific surface area, oil absorption amount, and the like are within the range of the true spherical silica particles. In addition, spherical and true spherical particles are more preferable from the viewpoint of the attacking property to the sliding partner material and kneading properties.

  The concave portion 6 filled with the resin portion 3 can be formed simultaneously with the sizing after the sintering and before the injection molding of the resin portion 3 in addition to the formation of the compaction of the bearing body 2 as described above. If it is intended to obtain adhesion with the resin part 3 due to the anchor effect as in this embodiment, it is desirable to form the recess 6 at the stage of compacting. If the generation of the cutting powder is not particularly problematic, for example, the cutting powder can be enclosed in the bearing body 2 by molding the resin portion 3 or can be easily removed by post-processing. It is also possible to form

  From the viewpoint of adhesion, when sizing the bearing body 2 before injection molding, it is preferable to remove the surface of the recess 6. This is because a large number of apertures exist on the surface of the recess 6 after sintering and before sizing. Moreover, it is because the fixing force with resin increases also by performing the injection molding of the resin part 3 in the state in which the unevenness | corrugation of surface roughness order remained on the surface.

  It is also effective to provide a large-diameter portion at one end or both ends in the axial direction of the resin portion 3 as means for preventing the resin portion 3 from coming off in the axial direction. For example, as shown in FIG. 1, a large-diameter portion 7 that has an annular shape and engages with the bearing body 2 at both ends can be continuously formed with a plurality of resin portions 3 that are injection-molded in each recess 6. . By forming the plurality of resin parts 3 together with the large diameter part 7 in this way, the resin parts 3 can be connected by the large diameter part 7 and the resin part 3 can be prevented from coming off from the bearing body 2. it can.

  Moreover, the resin part 3 and the recessed part 6 are not restricted to an illustrated form, It is possible to take a various form. FIG. 5 shows an example thereof. In the sliding bearing 11 shown in FIG. 5, the shape of the recess 16 formed on the inner periphery of the bearing body 12 and the shape of the resin portion 13 filled in the recess 16 are shown in FIG. 1 is different from the concave portion 6 and the resin portion 3 of the sliding bearing 1 shown in FIG.

  Specifically, the recess 16 has an inclined groove shape, and both ends thereof extend to positions where the both ends of the bearing body 12 are opened. In FIG. 5, a plurality of inclined groove-like recesses 16 are arranged in parallel with each other, and the same number of resin parts 13 as the recesses 16 are formed by injection molding the resin into the plurality of recesses 16. At this time, it is preferable that the cross-sectional shape of the recess 16 is substantially triangular in consideration of the moldability of the recess 16.

  By forming the recess 16 and the resin portion 13 as described above, a plurality of first bearing surfaces 14 and a plurality of second bearing surfaces 15 having a smaller diameter than the first bearing surface 14 are formed. With this configuration, the shaft inserted through the inner periphery comes into sliding contact with the resin-made second bearing surface 15 at a plurality of locations, so that the contact area between the second bearing surface 15 and the shaft is moderately dispersed. The As a result, the durability of the second bearing surface 15 can be improved and the service life of the sliding bearing 11 can be extended. Or although illustration is abbreviate | omitted, the effect | action similar to the above-mentioned effect | action can be acquired also by arrange | positioning one inclined groove-shaped recessed part in a spiral shape, and filling and forming the resin part in this spiral-shaped recessed part. Is possible.

  In the sliding bearings 1 and 11 illustrated in FIG. 1 and FIG. 5, the second bearing surfaces 5 and 15 have a convex curved surface shape, but are not particularly limited to this shape. Depending on the outer diameter of the shaft 8, the inner diameter of the first bearing surface 4, and the distance between the resin parts 3 (second bearing surface 5), the cross-sectional contour such as a convex semicircular shape, a convex arc shape, or a concave arc shape is used. The second bearing surface 5 or the resin portion 3 may be used.

  In addition, although all the recessed parts 6 and 16 illustrated in the figure have shapes that are open at both ends in the axial direction of the bearing bodies 2 and 12, they may be shapes that are open only at one end. Further, the shape of the recesses 6 and 16 is not particularly limited to the groove shape. As long as molding is possible at the time of compacting or sizing, or as long as the resin portion can be filled and formed, concave portions having various shapes can be formed.

  Further, the resin portion is not necessarily formed in the recess. Various forms are possible as long as the bearing form can be changed according to the radial load (the bearing surface can be selected). It is also possible to partially coat the resin portion on the perfect circular inner peripheral surface of the bearing body. However, in this case, it is better to form the bearing body from a sintered metal in consideration of adhesion to the resin portion. Alternatively, if the adhesion with the resin portion can be ensured, or if the slidability (low friction) with the shaft can be ensured, the bearing body can be formed of a metal material having no internal voids. is there.

  From the above description, the sliding bearing according to the present invention as well as the present embodiment can exhibit excellent slidability and wear resistance under both high load and low load. Therefore, as described above, it can be suitably used for a load configuration in which the radial load gradually increases from the start of rotation, or a configuration in which the radial load increases suddenly. Moreover, it can be used suitably also when using the same kind of plain bearing in the several location from which the magnitude | size of the load to receive differs.

The sliding bearing which concerns on one Embodiment of this invention is shown, and it is the longitudinal cross-sectional view seen from the direction of arrow B in FIG. FIG. 2 is a cross-sectional view of the plain bearing shown in FIG. 1 viewed from the direction of arrow A. It is sectional drawing to which the recessed part periphery of the sliding bearing was expanded. It is a figure which shows the support form of an axis | shaft conceptually, Comprising: (a) is the state which supports the radial load from an axis | shaft with the 2nd bearing surface made from resin, (b) is the 1st bearing surface made from a sintered metal. It is sectional drawing which shows notionally the state which supports the radial load from an axis | shaft, respectively. It is a longitudinal cross-sectional view of the sliding bearing which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11 Sliding bearing 2, 12 Bearing main body 3, 13 Resin part 4, 14 1st bearing surface 5, 15 2nd bearing surface 6, 16 Recessed part 7 Large diameter part 8 Axis

Claims (7)

A sliding bearing having a first bearing surface and a second bearing surface on the inner periphery of a metal bearing body,
The first bearing surface is composed of an inner peripheral surface of the bearing body, the second bearing surface is composed of a surface of a resin portion provided on the inner periphery of the bearing body, and the second bearing surface is It is formed with a smaller diameter than the first bearing surface,
According to the radial load from the shaft inserted through the inner periphery of the bearing body, the radial load is supported by the second bearing surface, and the radial load is supported by the first bearing surface. Plain bearing.   The sliding bearing according to claim 1, wherein a concave portion is formed on an inner periphery of the bearing body, and the resin portion is filled in the concave portion.   The sliding bearing according to claim 1, wherein the resin portion contains a lubricating component.   The sliding bearing according to claim 2, wherein the concave portion has a groove shape, and the groove-shaped concave portion extends to at least one end surface of the bearing body. It is a manufacturing method of the sliding bearing of Claim 1, Comprising:
A sliding bearing in which the bearing body having the first bearing surface and a recess on an inner periphery is formed of sintered metal, and the resin portion is injection-molded in the recess to form the second bearing surface in the resin portion. Production method.   The sliding bearing manufacturing method according to claim 5, wherein after the first bearing surface of the bearing body formed of sintered metal is sized, injection molding of the resin portion into the recess is performed.   The sliding bearing manufacturing method according to claim 5, wherein after the resin portion is injection-molded in the concave portion, the first bearing surface and the surface of the resin portion serving as the second bearing surface are both sized.

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