JP2016180440A - Radial sliding bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radial sliding bearing which can reduce restrictions during injection molding, suppresses the alignment disorder of a filling material or the generation of weld, and is composed of a base material and a resin layer.SOLUTION: A radial sliding bearing 1 has a cylindrical base material 2, and a resin layer 3 formed on an inner diameter surface 2a of the cylindrical base material 2. The cylindrical base material 2 has a tapered surface 4 connecting an end surface 2c on an end portion side and the inner diameter surface 2a at the end portion 2b. The diametrical width W of the tapered surface 4 is larger than the layer thickness Tof the resin layer 3, and the resin layer 3 is formed by injection-molding a resin composition using a gate 5 provided within a range on an axial extension line of the tapered surface 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sliding bearing with high lubrication stability and high rotational accuracy, and more particularly to a radial sliding bearing in which a resin layer is formed on the inner diameter surface of a metal substrate.

  Conventionally, a sliding bearing in which a porous sintered metal is impregnated with oil is known as a sliding bearing with high rotational accuracy. If this sliding bearing is used by impregnating a sintered metal-based porous material with oil, the oil can be continuously supplied to the sliding interface. Is possible. The counterpart material with which such a sliding bearing comes into contact is usually the same metal material as the sliding bearing, so there is no concern about so-called “drilling or slipping” due to differences in linear expansion, and the processing accuracy is increased and rotation is improved. Suitable for applications that require accuracy. In addition to the above-mentioned sliding bearings having self-lubricating properties, known are those in which a solid lubricant such as polytetrafluoroethylene resin, graphite, or molybdenum disulfide is blended with a resin, or a lubricant or wax is blended. It has been.

  However, the sliding bearing used by impregnating the porous sintered metal with oil may wear the mating material when the shaft or the mating material to be fixed is a soft material, and the supply of lubricating oil is interrupted. In some cases, metal contact may occur. In particular, when a resin material with better sliding characteristics is used as the material of the sliding bearing, if the counterpart material is a soft material, the shaft may be stiffened due to shrinkage and expansion of the resin without attacking it. In addition, it is necessary to set a large clearance between the bearings, which deteriorates the rotational accuracy.

  For this reason, a metal is used as the outer periphery of the bearing, a resin layer is formed by insert molding of a resin material on the sliding portion of the outer periphery of the bearing, and at least a bearing in contact with the resin layer on the surface of the outer periphery of the bearing A fine concave portion is provided on the surface portion of the outer peripheral portion, (the linear expansion coefficient of the resin material) × (thickness of the resin layer) in the resin layer is 0.15 or less, and the total apparent area occupied by the concave portion is defined as the resin layer A high-accuracy plain bearing having a surface area of 25 to 95% of a surface portion of a bearing outer peripheral portion in contact with the bearing is known (see Patent Document 1).

  Further, in such a high-precision sliding bearing, the gate trace at the time of injection molding may adversely affect the bearing performance, and the processing of the gate trace may increase the production process, resulting in poor productivity. In order to cope with such a problem, there is known a high-precision sliding bearing that employs insert molding through a tunnel gate when a resin layer is formed on a sintered metal (see Patent Document 2).

  Such a high-precision sliding bearing is used for a photosensitive drum, a developing unit, a supporting unit for a fixing unit, or a carriage bearing of a copying machine or a printer. However, this conventional high-accuracy plain bearing does not have sufficient characteristics with respect to the wear resistance of the resin layer, so that it may be difficult to use it in a portion with high load and high rotation. For example, to support the rotating shafts of compressors for room air conditioners and car air conditioners, and to support the rotating shafts of transmissions such as automobiles and construction machinery, precise rotational accuracy is required and a large radial load is required. It may be difficult to use as a sliding bearing for receiving.

  As a composite sliding bearing that solves the problems described above, a resin layer is integrally provided on the sintered metal base of the bearing, and this resin layer is a state in which fibrous filler is dispersed in an aromatic polyether ketone resin. The fibrous filler is oriented so that the length direction of the fiber intersects with the rotation direction of the bearing at 45 to 90 degrees, and the resin layer has a layer thickness of 0.1. There is known a compound plain bearing characterized by being provided at ˜0.7 mm (see Patent Document 3).

JP 2003-239976 A JP-A-2005-333781 JP 2012-077764 A

  The composite sliding bearing of Patent Document 3 can be used as a sliding bearing that receives a relatively large radial load, such as a rotary shaft of a compressor for a room air conditioner or a compressor for a car air conditioner, a transmission of an automobile, a construction machine, or the like. It is known as a high-precision sliding bearing with improved loadability, heat resistance, low friction characteristics, and wear resistance characteristics. However, since the thickness of the resin layer is as thin as 0.1 to 0.7 mm, various restrictions are necessary to form the resin layer by injection molding.

For example, the melt viscosity at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ of the aromatic polyetherketone resin composition needs to be 50 to 200 Pa · s. In addition, the orientation of the fibrous filler is oriented in a wide range of 45 to 90 degrees with respect to the direction of motion of the sliding bearing, and it is difficult to align the orientation beyond that, which limits the suppression of wear of the mating material. there were. In order to align the orientation of the fibrous filler, it is necessary to dispose the gate position on the thickness of the resin layer. In this case, there is a possibility that weld is strongly generated in the resin layer. The occurrence of welds may cause a decrease in roundness and a decrease in mechanical strength.

  The present invention has been made in order to cope with such problems, and in a configuration including a cylindrical base material and a resin layer insert-molded on the inner diameter surface thereof, the restriction during injection molding can be reduced, and the filler An object of the present invention is to provide a radial plain bearing capable of suppressing the occurrence of orientation disorder and welds.

  The radial plain bearing of the present invention is a radial plain bearing having a cylindrical base material and a resin layer formed on the inner diameter surface of the cylindrical base material, wherein the cylindrical base material has at least one end portion. A taper surface connecting the end surface on the end side and the inner diameter surface, and the radial width of the taper surface is larger than the thickness of the resin layer, and the resin layer extends in the axial direction of the taper surface. It is formed by injection molding of a resin composition using a gate provided in the upper range.

  The approach angle of the tapered surface is 30 to 50 degrees. Here, the penetration angle of the tapered surface refers to an angle formed by the tapered surface and the inner diameter surface in the cylindrical base material.

  The cylindrical base material is made of metal, and the layer thickness of the resin layer is 0.1 to 1.0 mm.

  The cylindrical base material is made of sintered metal, and the resin composition is formed by blending a fibrous filler with a synthetic resin. The fibrous filler has an aspect ratio of 3 or more, and the length direction of the fibers is oriented at 0 to 30 degrees with respect to the axial direction of the bearing. The synthetic resin is an aromatic polyether ketone resin.

  The thickness of the resin layer is 1/8 to 1/2 of the thickness of the cylindrical base material.

  The radial plain bearing of the present invention has a cylindrical base material and a resin layer formed on the inner diameter surface of the cylindrical base material, and the cylindrical base material has at least one end on the end side. Resin that has a tapered surface that connects the end surface and the inner diameter surface, the radial width of the tapered surface is larger than the thickness of the resin layer, and the resin layer is a resin that uses a gate provided within the axial extension of the tapered surface Since it is formed by injection molding of the composition, the flow of the molten resin from the gate at the time of manufacture becomes very smooth. That is, since the injection-molded gate is provided within a range on the axial extension of the tapered surface of the cylindrical base material, the molten resin injected from the gate hits the tapered surface of the cylindrical base material and collides with it. The molten resin flows along the tapered surface without rebounding in the gate direction, the molten resin flows smoothly, and the orientation of the resin in the resin layer is not disturbed. In addition, since the gate is arranged at a position away from the resin layer (thin wall portion formed on the inner diameter surface) in the radial direction, weld does not occur strongly on the surface of the resin layer. Reduction in mechanical strength can be prevented.

  By setting the approach angle of the tapered surface of the cylindrical base material to 30 to 50 degrees, the flow of the molten resin is further smoothed.

  Since the flow of the molten resin is smooth as described above, even if the thickness of the resin layer is as thin as 0.1 to 1.0 mm, it can be molded without causing a short shot. Further, by making the cylindrical base material metal, it is possible to reduce the risk of the resin peeling even if the thickness of the resin layer is 0.1 to 1.0 mm.

  By using a sintered metal for the cylindrical base material, heat is easily radiated from the resin layer to the base material and from the base material to the outside. Further, since the surface is uneven, the surface area is large, the anchor effect with the resin layer is high, and the adhesion strength can be increased.

  Moreover, since the said resin composition mix | blends a fibrous filler with a synthetic resin, the abrasion resistance of a resin layer becomes high and a bearing life improves. Moreover, a reinforcing effect becomes high by making a fibrous filler into the aspect-ratio 3 or more. Furthermore, by orienting the length direction of the fiber at 0 to 30 degrees with respect to the axial direction of the bearing, the edge of the fibrous filler attacks the shaft that is the mating material and the mating material has an opportunity to wear damage. The friction coefficient during rotation of the bearing is reduced and the torque fluctuation of the bearing is low and stable.

  In addition, since the synthetic resin is an aromatic polyetherketone resin, the continuous use temperature is 250 ° C. and high heat resistance, friction and wear characteristics, creep resistance, seizure resistance, various chemical resistance, oil resistance Can be obtained.

  Since the thickness of the resin layer is 1/8 to 1/2 of the thickness of the cylindrical base material, creep of the resin layer can be prevented. Furthermore, heat generated by frictional heat is likely to escape from the friction surface to the bearing base material, it is difficult to store heat, load resistance is high, and the amount of change is small even under high surface pressure. Thereby, the real contact area on the friction surface is also reduced, the frictional force and the frictional heat generation are reduced, and wear can be reduced and the increase in the friction surface temperature can be suppressed.

  This radial plain bearing has the advantage that it can withstand high loads and ensure high-precision rotational stability, both as a dry bearing that does not use a lubricant and as a liquid lubrication bearing that is lubricated with oil or grease. is there.

It is sectional drawing and a perspective view which show an example of the radial sliding bearing of this invention. It is sectional drawing and the perspective view which show the other example of the radial sliding bearing of this invention. It is sectional drawing which shows an example of the conventional radial sliding bearing.

  An example of the radial plain bearing of the present invention will be described with reference to FIG. FIG. 1A is a sectional view of a radial plain bearing, and FIG. 1B is a perspective view thereof. As shown in FIG. 1A, the radial plain bearing 1 has a cylindrical base material 2 and a resin layer 3 formed on the inner diameter surface 2 a of the cylindrical base material 2. The cylindrical base material 2 has a tapered surface 4 connecting the end surface 2c on the side of the end 2b and the inner diameter surface 2a at one axial end 2b. The tapered surface 4 is a surface that is represented by a straight line (inclined line) connecting the end surface 2c and the inner diameter surface 2a when viewed in the axial sectional view of the sliding bearing, and is continuous in the circumferential direction at the same inclination angle. Here, the gate 5 at the time of injection molding is provided within the range on the axial direction extension on the end 2b side of the tapered surface 4 (within the range of the radial width W of the tapered surface 4). At the time of injection molding, the cylindrical base material 2 is inserted into the mold, and the resin layer 3 is formed by injection filling molten resin into the cavity of the mold (insert molding). In the form shown in FIG. 1, the resin layer 3 is formed so as to cover the entire inner diameter surface 2 a and end surface 2 c of the cylindrical base material 2.

  The gate 5 is located on the end surface (bearing end surface) of the resin layer 3 and is provided as a pin gate. The number of gates 5 can be set to any number, but it can be 3 to 12 gates with equal intervals in the circumferential direction because the roundness of the bearing surface can be reduced according to the size of the bearing. Is preferred. In the case where the gates 5 are provided, all of them are arranged so as to fall within the range on the extension in the axial direction on the end 2b side of the tapered surface 4 (within the range of the radial width W of the tapered surface 4). In addition, it is preferable that the radial position with respect to the tapered surface 4 within the range is also aligned. In FIG. 1B, the gate position is omitted.

  The approach angle θ of the tapered surface 4 is preferably set to 30 to 50 degrees. If it exceeds 50 degrees, the fluidity of the molten resin may be reduced. On the other hand, if the angle is less than 30 degrees, the length of the thick portion (thickened by the taper) of the resin layer 3 becomes long, and the dimensional change of the resin layer 3 may occur.

  Another example of the radial plain bearing of the present invention will be described with reference to FIG. FIG. 2A shows a sectional view of the radial plain bearing, and FIG. 2B shows a perspective view thereof. As shown in FIG. 2A, the radial bearing 1 has a cylindrical base material 2 and a resin layer 3 formed on the inner diameter surface 2 a of the cylindrical base material 2. The cylindrical base material 2 has a tapered surface 4 connecting the end surface 2c on the side of the end 2b and the inner diameter surface 2a at one axial end 2b. Here, the resin layer is not formed on the end surface 2c, and the end surface 2c is exposed to the bearing end surface. In this embodiment, since the distance between the taper surface 4 and the gate 5 is reduced by the thickness of the resin layer on the end surface 2c side, the angle of the taper surface is preferably set slightly smaller than in the case of FIG.

  Here, FIG. 3 shows an example of a conventional radial plain bearing. The radial plain bearing 11 of FIG. 3 has the same appearance as the radial plain bearing of FIG. 1 and includes a cylindrical base 12 and a resin layer 13 formed on the inner diameter surface 12a of the cylindrical base 12. Have. The resin layer 13 is insert-molded with respect to the cylindrical base material 12. The gate 15 is located on the end surface (bearing end surface) of the resin layer 13. In this case, there is a possibility that the molten resin injected from the gate 15 hits the end surface of the cylindrical base member 12 and bounces back, so that it cannot flow smoothly. In particular, when the resin layer 13 is thin (0.1 to 1.0 mm), there is a risk of short shots.

  On the other hand, as shown in FIGS. 1A and 2A, in the present invention, the tapered surface 4 and the gate 5 of the cylindrical base material 2 are arranged as described above. The molten resin injected from the gate 5 at the time of molding hits the tapered surface 4, and the collided molten resin flows along the tapered surface 4 without rebounding in the direction of the gate 5, and on the inner diameter surface 2 a of the cylindrical substrate 2. It flows smoothly throughout the thin resin layer 3. Thereby, even if the layer thickness of the resin layer 3 is thin (0.1-1.0 mm), it can shape | mold without becoming a short shot. In addition, weld does not occur strongly on the surface of the resin layer, and it is possible to prevent a decrease in roundness and a decrease in mechanical strength due to the weld. As a result, the physical properties of the bearing can be improved. In the final radial plain bearing, the gate 5 remains as a gate trace, or the gate trace may be removed by post-processing as necessary.

The radial width W of the tapered surface 4 is larger than the layer thickness T ₁ of the resin layer 3. For this reason, it becomes easy to allow the molten resin to flow from the tapered surface 4 into the thin resin layer 3 portion on the inner diameter surface 2a of the cylindrical base material 2 during injection molding. Further, since the tapered surface 4 is a surface connecting the end surface 2 c of the cylindrical substrate 2 and the inner diameter surface 2 a, the radial width W thereof is smaller than the thickness T ₂ of the cylindrical substrate 2. In FIGS. 1 and 2, the tapered surface is formed only at one end of the cylindrical base material, but is not limited thereto, and may be formed at both ends.

The thickness _{T 1} of the resin layer 3, 0.1 to 1.0 mm is preferred. The layer thickness T ₁ is the portion formed on the inner diameter surface 2 a of the cylindrical substrate 2 excluding the bearing end surface and the tapered surface 4 as shown in FIG. 1 (a) and FIG. 2 (a). This is the radial thickness of the layer (constant thickness). The preferred range is set in consideration of the insert molding surface and physical properties. When the thickness of the resin layer is less than 0.1 mm, insert molding is difficult. Further, the durability during long-term use may be inferior, that is, the life may be shortened. On the other hand, if the thickness of the resin layer exceeds 1.0 mm, sink marks may occur and dimensional accuracy may be reduced. In addition, heat due to friction is difficult to escape from the friction surface to the substrate, and the friction surface temperature may increase. Further, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and the frictional heat generation increase, and the seizure resistance may decrease. In consideration of heat dissipation of the frictional heat to the base material, the layer thickness of the resin layer is more preferably 0.2 to 0.5 mm. In addition, when high dimensional accuracy is required, you may finish to required resin thickness by machining after insert molding. Further, the inner diameter may be finished according to the shaft diameter of the counterpart shaft after being assembled to the housing.

The layer thickness T ₁ of the resin layer 3 is preferably 1/8 to 1/2 of the wall thickness T ₂ of the cylindrical substrate 2. When the layer thickness of the resin layer is less than 1/8 of the thickness of the base material, the resin layer becomes too thin relative to the base material, which may deteriorate durability during long-term use. On the other hand, if the thickness of the resin layer exceeds 1/2 of the thickness of the base material, the resin layer becomes too thick relative to the base material, and heat due to friction is difficult to escape from the friction surface to the base material. The surface temperature increases. In addition, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and the frictional heat generation increase, and the seizure resistance may decrease.

  The cylindrical substrate 2 is preferably made of metal, and particularly preferably made of sintered metal. By using a sintered metal base material, the molten resin penetrates deeply into the irregularities on the surface of the base material at the time of injection molding, and the resin layer and the base material adhere firmly. Examples of the material of the sintered metal include iron, copper iron, copper, and stainless steel. In view of excellent adhesion between the substrate and the resin layer, it is preferable to employ a sintered metal whose main component is iron (which may include copper). In addition, since copper is inferior to adhesiveness (adhesiveness) with resin rather than iron, when copper is included, content of copper is 10 weight% or less. More preferably, the copper content is 5% by weight or less.

  If there is oil adhesion or oil impregnation on the sintered metal base material, the oil residue that decomposes and gasifies during the injection molding of the resin layer is present at the interface, so the adhesion between the resin layer and the base material is good. May decrease. Therefore, it is preferable to use a sintered metal not impregnated with oil for the base material before forming the resin layer. Moreover, when using oil in the process of shaping | molding or re-pressing (sizing) of a sintered metal, it is preferable to set it as the non-oil-containing sintered metal which removed oil by solvent washing etc.

  The base material made of sintered metal with iron as the main component is treated with steam to unintentionally adhere to the sintered surface during the molding or re-pressing (sizing) process, or oil or deposits that have penetrated inside. Since there is an effect of removing water, variation in adhesion with the resin layer is small and stable. Moreover, antirust property can also be provided to the base material made of sintered metal. The conditions for the steam treatment are not particularly limited, but a method of spraying steam heated to about 500 ° C. is common.

  The theoretical density ratio of the sintered metal base material is preferably 0.7 to 0.9. The theoretical density ratio of the material is the ratio of the density of the base material when the theoretical density of the material (density when the porosity is 0%) is 1. If the theoretical density ratio is less than 0.7, the strength of the base material becomes low, and the base material may be cracked by the injection molding pressure at the time of insert molding. On the other hand, when the theoretical density ratio exceeds 0.9, the unevenness is reduced, so that the surface area and the anchor effect are lowered, and the adhesion with the resin layer is lowered. More preferably, the theoretical density ratio of the materials is 0.72 to 0.84.

  The resin composition forming the resin layer 3 is not particularly limited as long as it can be injection-molded with a thin wall and satisfies the required characteristics of a radial sliding bearing. Since the continuous use temperature is 250 ° C. and excellent in heat resistance, oil resistance / chemical resistance, creep resistance, and friction and wear characteristics, it is preferable to use a resin composition based on an aromatic polyether ketone resin. . In addition, aromatic polyetherketone resins have high toughness, high mechanical properties at high temperatures, and excellent fatigue resistance and impact resistance. The layer is difficult to peel from the substrate.

  Examples of the aromatic polyether ketone resin that can be used in the present invention include polyether ether ketone (PEEK) resin, polyether ketone (PEK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin. Examples of commercially available PEEK resins that can be used in the present invention include: Victorex: PEEK (90P, 150P, 380P, 450P, 90G, 150G, etc.), Solvay Advanced Polymers: KetaSpire (KT-820P, KT-880P) Etc., manufactured by Daicel Degussa, Inc .: VESTAKEEEP (1000G, 2000G, 3000G, 4000G, etc.). Examples of the PEK resin include Victrex-HT manufactured by Victrex, and examples of the PEKKK resin include Victrex-ST manufactured by Victrex.

  The resin composition for forming the resin layer uses the above aromatic polyetherketone resin as a base resin, and a fiber filler such as glass fiber, carbon fiber, aramid fiber, whisker or the like is mixed in a dispersed state. Can do. Thereby, the mechanical strength of the resin layer can be further improved. In particular, in the radial sliding bearing of the present invention, since the resin layer is thin (0.1 to 1.0 mm), improvement in mechanical strength is desirable.

  In addition to fibrous fillers, solid lubricants such as polytetrafluoroethylene (PTFE) resin, graphite and molybdenum disulfide, and inorganic fillers such as calcium carbonate, calcium sulfate, mica and talc can also be blended. is there. By blending the above-mentioned solid lubricant, it is possible to improve the seizure resistance by reducing friction even under non-lubricated conditions and even when the lubricating oil is dilute. Moreover, creep resistance can be improved by mix | blending the said inorganic filler.

  Fibrous fillers, inorganic solid lubricants (such as graphite and molybdenum disulfide), and inorganic fillers have the effect of reducing the molding shrinkage of aromatic polyether ketone resins. Therefore, there is also an effect of suppressing the internal stress of the resin layer at the time of insert molding with the sintered metal base material.

  The fibrous filler has an aspect ratio of 3 or more, and the length direction of the fiber is preferably oriented at 0 to 30 degrees with respect to the axial direction of the bearing. Needle-like or fibrous fillers have a sharp edge with an edge of 90 degrees or less, so when the filler edge is in the direction of movement of the sliding bearing, the sliding contact material is physically worn. It is easy to damage and the coefficient of friction is difficult to stabilize. On the other hand, by orienting the fiber length direction of the fibrous filler to 0 to 30 degrees with respect to the axial direction of the bearing, the sliding contact material is hardly damaged by wear and the friction coefficient is also stabilized. It should be noted that the orientation of the fibrous filler is preferably closer to 0 degrees because there is less abrasion damage due to the edge of the filler and the friction coefficient is stable. If it is 0 to 30 degrees, wear damage is extremely reduced.

  The average fiber length of the fibrous filler is preferably 0.02 to 0.2 mm. If the thickness is less than 0.02 mm, a sufficient reinforcing effect cannot be obtained, and creep resistance and wear resistance may not be satisfied. When the thickness exceeds 0.2 mm, the ratio of the fiber length to the layer thickness of the resin layer becomes large, so that the thin moldability is poor. In order to further improve the stability of thin-wall molding, an average fiber length of 0.02 to 0.1 mm is preferable.

  Among the fibrous fillers, it is preferable to use carbon fibers. Carbon fiber has a strong orientation in the melt flow direction of the resin when the resin layer is molded. The carbon fibers used in the present invention may be either pitch-based or PAN-based ones classified from raw materials, but PAN-based carbon fibers having a high elastic modulus are preferred. The firing temperature is not particularly limited, but a carbonized product fired at about 1000 to 1500 ° C. is higher than that fired at a high temperature of 2000 ° C. or higher and converted to graphite (graphite). Even under PV, it is preferable because the sliding contact material is not easily damaged by wear.

  The average fiber diameter of the carbon fibers is 20 μm or less, preferably 5 to 15 μm. Thick carbon fiber exceeding this range generates extreme pressure, so the effect of improving load resistance is poor, and when the sliding contact material is an aluminum alloy or non-quenched steel material, wear damage of the counterpart material is increased, which is preferable. Absent. The carbon fiber may be a chopped fiber or a milled fiber, but a milled fiber having a fiber length of less than 1 mm is preferable in order to obtain stable thin-wall formability.

  The resin composition forming the resin layer preferably uses the above aromatic polyether ketone resin as a base resin, and contains carbon fibers and a PTFE resin as a solid lubricant as essential components.

  As the PTFE resin, any of molding powder by suspension polymerization, fine powder by emulsion polymerization, and recycled PTFE may be used. In order to stabilize the fluidity of the resin composition when an aromatic polyetherketone resin is used as a base resin, it is preferable to employ recycled PTFE that is difficult to be fiberized by shearing during molding and that does not easily increase the melt viscosity. .

  Regenerated PTFE is a powder that has been irradiated with a heat-treated powder (heated history added), γ-rays or electron beams. For example, a powder obtained by heat-treating molding powder or fine powder, a powder obtained by further irradiating this powder with γ-rays or an electron beam, a powder obtained by pulverizing a molding powder or a molded product of fine powder, and then a γ-ray or electron beam. There are types such as irradiated powder, molding powder or fine powder irradiated with gamma rays or electron beams. Among the regenerated PTFE, a resin composition comprising an aromatic polyether ketone resin as a base resin that does not aggregate, does not fiberize at the melting temperature of the aromatic polyether ketone resin, has an internal lubricating effect, and Since fluidity can be stably improved, it is more preferable to use PTFE resin irradiated with γ rays or electron beams.

  In addition, you may mix | blend a well-known resin additive with respect to the resin composition which forms a resin layer to such an extent that the effect of this invention is not inhibited. Examples of the additive include friction property improvers such as boron nitride, colorants such as carbon powder, iron oxide, and titanium oxide, and thermal conductivity improvers such as graphite and metal oxide powder.

  The resin composition for forming the resin layer preferably includes an aromatic polyether ketone resin as a base resin, 5 to 30% by volume of carbon fiber, and 1 to 30% by volume of PTFE resin as essential components. The balance excluding this essential component and other additives is an aromatic polyether ketone resin. By adopting this blending ratio, even under high PV conditions, the deformation and wear of the resin layer, the aggressiveness against the sliding contact material are small, and the resistance to oil and the like is also high. Further, the carbon fiber is more preferably 5 to 20% by volume, and the PTFE resin is more preferably 2 to 25% by volume.

  When the blending ratio of the carbon fiber exceeds 30% by volume, the melt fluidity is remarkably lowered and it becomes difficult to form a thin wall, and when the sliding contact material is an aluminum alloy or an unquenched steel material, there is a risk of wear damage. . Moreover, when the blending ratio of the carbon fiber is less than 5% by volume, the effect of reinforcing the resin layer is poor, and sufficient creep resistance and wear resistance may not be obtained.

  If the blending ratio of the PTFE resin exceeds 30% by volume, the wear resistance and creep resistance may be lowered from the required levels. In addition, when the blending ratio of the PTFE resin is less than 1% by volume, the effect of imparting the required lubricity to the composition is poor, and sufficient sliding characteristics may not be obtained.

  The means for mixing and kneading the above raw materials is not particularly limited, and only the powder raw material is dry-mixed with a Henschel mixer, ball mixer, ribbon blender, ladyge mixer, ultra Henschel mixer, etc. Melting and kneading can be performed with a melt extruder such as an extruder to obtain molding pellets (granules). In addition, a side feed may be used for charging the filler when melt kneading with a twin screw extruder or the like. Using this molding pellet, a resin layer is injection-molded by insert molding on a cylindrical base material by the method described above.

The resin composition forming the resin layer preferably has a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ . When the melt viscosity is within this range, precise molding and fibrous filler can be oriented at a predetermined angle, and a thin insert molding with a layer thickness of 0.1 to 1.0 mm on the surface of a cylindrical substrate Can be done smoothly. By making thin insert molding possible and making post-processing after insert molding unnecessary, manufacturing becomes easy and manufacturing costs can be reduced.

In order to set the melt viscosity at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ to 50 to 200 Pa · s, it is preferable to employ an aromatic polyether ketone resin having a melt viscosity of 150 Pa · s or less under these conditions. Examples of such aromatic polyetherketone resins include Victorex Corporation: PEEK (150P, 90P, 150G, 90G), Solvay Advanced Polymers Corporation: KetaSpire (KT-880P), and the like.

  When the radial plain bearing of the present invention is used as a radial bearing for sliding parts where hydraulic oil, refrigeration oil, lubricating oil, transmission oil, engine oil, brake oil, or grease, or grease is present, lubricate the friction surface of the resin layer. By forming the groove, more stable low friction and low wear characteristics can be obtained.

  The radial plain bearing of the present invention has a configuration comprising a cylindrical base material and a resin layer insert-molded on the inner surface thereof, so that restrictions during injection molding can be reduced, and disorder of orientation such as fillers and generation of welds can be prevented. Therefore, it can be suitably used as a radial slide bearing for supporting a rotating shaft of a compressor such as a room air conditioner or a car air conditioner, or for supporting a rotating shaft of a transmission such as an automobile or construction machine.

DESCRIPTION OF SYMBOLS 1 Radial slide bearing 2 Cylindrical base material 3 Resin layer 4 Tapered surface 5 Gate

Claims (7)

A radial sliding bearing having a cylindrical base material and a resin layer formed on the inner diameter surface of the cylindrical base material,
The cylindrical substrate has a tapered surface connecting the end surface on the end side and the inner diameter surface at least one end portion;
The radial width of the tapered surface is larger than the layer thickness of the resin layer,
The radial sliding bearing according to claim 1, wherein the resin layer is formed by injection molding of a resin composition using a gate provided in an axial extension of the tapered surface.   The radial sliding bearing according to claim 1, wherein an approach angle of the tapered surface is 30 to 50 degrees.   The radial plain bearing according to claim 1 or 2, wherein the cylindrical base material is made of metal, and the thickness of the resin layer is 0.1 to 1.0 mm.   The radial slip according to claim 1, 2 or 3, wherein the cylindrical substrate is made of sintered metal, and the resin composition is formed by blending a synthetic resin with a fibrous filler. bearing.   The radial sliding bearing according to claim 4, wherein the fibrous filler has an aspect ratio of 3 or more, and the length direction of the fiber is oriented at 0 to 30 degrees with respect to the axial direction of the bearing.   The radial sliding bearing according to claim 4 or 5, wherein the synthetic resin is an aromatic polyether ketone resin.   The radial sliding bearing according to any one of claims 1 to 6, wherein a thickness of the resin layer is 1/8 to 1/2 of a thickness of the cylindrical base material.

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