Radial roller bearing

Abstract

Provided is a radial roller bearing that is capable of preventing falling of a roller and is capable of improving handleability and load resistance. The radial roller bearing comprises: a plurality of rollers that are arranged along the circumferential direction and that roll on at least one of the inner circumferential surface of a housing and the outer circumferential surface of a shaft; and a lubricant-containing polymer that holds the plurality of rollers.

Description

Radial roller bearings

[0001] The present invention relates to a radial roller bearing.

[0002] Radial roller bearings are generally used in various mechanical devices such as transmission gear supports and shaft supports in automobile transmissions. Conventional radial roller bearings are known to be equipped with a cage to prevent the rollers from coming loose and falling off before the bearing is assembled, or to hold the rollers at a predetermined interval in the circumferential direction.

[0003] The retainers for radial roller bearings described in Patent Documents 1 and 2 each have claws on the column portion or annular portion of the retainer to hold the rollers, thereby preventing the rollers from falling out radially to the outside or inside of the retainer.

[0004] Furthermore, Patent Document 3 discloses a cylindrical roller fall-out prevention device for preventing rollers from falling off radially inward of a cage during transportation, etc. In the technology disclosed in Patent Document 3, after rollers are assembled into a cage that does not include means for preventing the rollers from falling off radially inward of the cage, the roller fall-out prevention device is disposed radially inward of a plurality of rollers arranged along the circumferential direction. As a result, the rollers are supported on the radial outside by the cage and on the radial inside by the roller fall-out prevention device, preventing them from falling off from the cage.

[0005] Japanese Patent Publication No. 2021-139422 Japanese Patent Publication No. 2001-099162 Japanese Patent Publication No. 2017-160931

[0006] However, even with cages that have a function to prevent rollers from falling off, such as those described in Patent Documents 1 and 2, it can be difficult to completely prevent the rollers from falling off when assembling the rollers and cage into a bearing. Also, if the cage has pillar portions or has a function to restrict radial movement of the rollers, it can be difficult to reduce the distance between adjacent rollers in the circumferential direction, making it difficult to increase the number of rollers and improve the load capacity.

[0007] Furthermore, the roller stopper described in Patent Document 3 is intended to prevent rollers from falling off mainly during transportation. In other words, the roller stopper needs to be removed before the bearing is installed in a rotating machine, and there are issues with handling, such as the inability to prevent rollers from falling off when the bearing is installed in a rotating machine.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a radial roller bearing that can prevent rollers from falling off and that can improve handling properties and load resistance.

[0009] The above object of the present invention is achieved by the following configuration: (1) A radial roller bearing comprising: a plurality of rollers arranged in a circumferential direction and rolling on at least one of an inner peripheral surface of a housing and an outer peripheral surface of a shaft; and a lubricant-containing polymer that holds the plurality of rollers.

[0010] According to the present invention, by holding the rollers with a lubricant-containing polymer, it is possible to provide a radial roller bearing that can prevent the rollers from falling off and that can improve handling properties and load resistance.

[0011] FIG. 1 is a perspective view of a radial roller bearing according to a first embodiment. FIGS. 2(a) and 2(b) are cross-sectional views perpendicular to the circumferential direction of the radial roller bearing according to the first embodiment, with FIG. 2(a) showing the radial roller bearing alone according to the first embodiment and FIG. 2(b) showing the radial roller bearing according to the first embodiment assembled into a rotary machine. FIG. 3 is a plan view of the radial roller bearing according to the first embodiment as seen from the radial direction. FIG. 4 is a cross-sectional view as seen from the direction of arrows A-A in FIG. 3. FIGS. 5(a) and 5(b) are cross-sectional views perpendicular to the circumferential direction of a radial roller bearing according to a modification of the first embodiment, with FIG. 5(a) showing the radial roller bearing according to the modification of the first embodiment assembled into a rotary machine. FIG. 6 is a perspective view of a radial roller bearing according to a second embodiment.

[0033] Figures 7(a) and (b) are cross-sectional views perpendicular to the circumferential direction of a radial roller bearing according to the second embodiment, with Figure 7(a) showing the radial roller bearing alone according to the second embodiment and Figure 7(b) showing the radial roller bearing according to the second embodiment assembled into a rotary machine. Figures 8(a) and (b) are cross-sectional views perpendicular to the circumferential direction of a radial roller bearing according to a modification of the second embodiment, with Figure 8(a) showing the radial roller bearing alone according to the modification of the second embodiment and Figure 8(b) showing the radial roller bearing according to the modification of the second embodiment assembled into a rotary machine.

[0012] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a radial roller bearing according to the first embodiment. Figs. 2(a) and 2(b) are cross-sectional views perpendicular to the circumferential direction of the radial roller bearing according to the first embodiment, with Fig. 2(a) showing the radial roller bearing alone according to the first embodiment and Fig. 2(b) showing the radial roller bearing according to the first embodiment incorporated into a rotary machine. Fig. 3 is a plan view of the radial roller bearing according to the first embodiment as seen from the radial direction. Fig. 4 is a cross-sectional view as seen from the direction of arrows A-A in Fig. 3.

[0013] As shown in FIGS. 1, 2(a), and 2(b), a radial roller bearing 10 includes a plurality of rollers 100 arranged circumferentially and a lubricant-containing polymer 20 that holds the rollers 100. In this embodiment, the radial roller bearing 10 does not include raceways such as an outer ring or an inner ring. That is, the rollers 100 are arranged so as to be in contact with the inner peripheral surface of a housing 200 and the outer peripheral surface of a shaft 300, and are held by the lubricant-containing polymer 20 so as to roll between the inner peripheral surface of the housing 200 and the outer peripheral surface of the shaft 300. Here, the housing 200 and the shaft 300 are components that constitute any rotating machine, and the inner peripheral surface of the housing 200 and the outer peripheral surface of the shaft 300 are arranged coaxially and are capable of relative rotation via a rolling bearing. In this embodiment, the shaft 300 is rotatably supported relative to the housing 200 by the radial roller bearing 10, which does not include raceways such as an outer ring or an inner ring.

[0014] The configuration of the lubricant-containing polymer 20 will be described in detail below. As shown in FIGS. 1 to 4 , the lubricant-containing polymer 20 is annularly formed so as to abut against both axial ends of a plurality of rollers 100 arranged in the circumferential direction. The lubricant-containing polymer 20 has a pair of coaxially arranged annular end portions 21, 21, and a plurality of axially extending portions 23 that axially connect the pair of annular end portions 21, 21 and fill the circumferential gaps between circumferentially adjacent rollers 100. The lubricant-containing polymer 20 also has a plurality of radially outer slits 25a that are arranged radially outward of the lubricant-containing polymer 20 and expose a portion of the rolling surface of the plurality of rollers 100, and a plurality of radially inner slits 25b that are arranged radially inward of the lubricant-containing polymer 20 and expose a portion of the rolling surface of each roller 100. The radially outer slits 25a and the radially inner slits 25b extend axially between circumferentially adjacent axially extending portions 23.

[0015] 4 in particular, the axially extending portion 23 is formed between the circumscribing circle and the inscribing circle of the rollers 100 in a cross section perpendicular to the axial direction, and is formed so as to fill the circumferential gap between circumferentially adjacent rollers 100. In other words, the outer peripheral surface 27 of the axially extending portion 23 is arc-shaped in cross section, and either substantially coincides with the circumscribing circle of the rollers 100 or is located slightly radially inward relative to the circumscribing circle of the rollers 100. Furthermore, the inner peripheral surface 29 of the axially extending portion 23 is arc-shaped in cross section, and either substantially coincides with the inscribing circle of the rollers 100 or is located slightly radially outward relative to the inscribing circle of the rollers 100.

[0016] 1 to 4 , the radially outer slit 25a is a circumferential gap formed between a pair of circumferentially adjacent outer circumferential surfaces 27, 27 when viewed from the radial direction. That is, the rolling surfaces of the rollers 100 exposed from the radially outer slit 25a contact the inner circumferential surface of the housing 200. The radially inner slit 25b is a circumferential gap formed between a pair of circumferentially adjacent inner circumferential surfaces 29, 29 when viewed from the radial direction. That is, the rolling surfaces of the rollers 100 exposed from the radially inner slit 25b contact the outer circumferential surface of the shaft 300. In the illustrated example, the circumferential width Wa of the radially outer slit 25a and the circumferential width Wb of the radially inner slit 25b are constant regardless of the axial position.

[0017] Furthermore, the radial roller bearing 10 of this embodiment does not have a cage and is referred to as a so-called full complement bearing. In a full complement bearing, circumferentially adjacent rollers 100 may be configured to contact each other in order to improve the load capacity. In such a case, the axially extending portion 23 is not formed near the circumference of the pitch circle P (see FIG. 4 ), where circumferentially adjacent rollers 100 contact each other. That is, as shown in particular in FIG. 2( a), a circumferential slit 25c is formed between the axially extending portion 23 radially outward from the pitch circle P and the axially extending portion 23 radially inward from the pitch circle P, allowing the rolling surfaces of circumferentially adjacent rollers 100 to face each other.

[0018] On the other hand, in a full complement bearing, there may be gaps between circumferentially adjacent rollers 100, and the circumferentially adjacent rollers 100 may not contact each other. In such cases, it is not necessarily necessary to form the circumferential slits 25c as shown in Figure 2(a).

[0019] The lubricant-containing polymer that can be used in the present invention is, for example, a raw material prepared by mixing a synthetic resin selected from the group of polyolefin-based resins having basically the same chemical structure, such as polyethylene, polypropylene, polybutylene, and polymethylpentene, with a lubricant such as a paraffinic hydrocarbon oil such as poly-α-olefin oil, a naphthenic hydrocarbon oil, a mineral oil, an ether oil such as dialkyldiphenyl ether oil, or an ester oil such as a phthalate ester, either alone or in the form of a mixture of oils, and heating the raw material to a temperature above the melting point of the resin to plasticize it, and then cooling it to solidify it. Various additives such as antioxidants, rust inhibitors, anti-wear agents, antifoaming agents, and extreme pressure agents may also be added to the lubricant in advance.

[0020] The composition ratio of the lubricant-containing polymer is 10 to 50% by weight of polyolefin resin and 90 to 50% by weight of lubricant, based on the total weight.

[0021] If the polyolefin resin is less than 10% by weight, a certain level of hardness and strength cannot be obtained, and for example, the lubricant-containing polymer 20 may not be able to retain the roller 100, or when a load is applied due to the rotation of the bearing, etc., it may become difficult to maintain the initial shape, increasing the possibility of problems such as the roller 100 falling out of the internal space of the bearing or rotating machine.

[0022] Furthermore, if the polyolefin resin exceeds 50% by weight (that is, if the lubricant is less than 50% by weight), the supply of lubricant to the bearing will be reduced, shortening the life of the bearing.

[0023] The group of synthetic resins has the same basic structure but different average molecular weights, ranging from 700 to 5×10 ６ That is, the average molecular weight ranges from 700 to 1 × 10 ４ waxes with an average molecular weight of 1 × 10４ ~1 x 10 ６ and those with a relatively low molecular weight of 1 × 10 ６ ~5 x 10 ６ These ultra-high molecular weight polymers are used alone or in combination as needed. By combining relatively low molecular weight polymers with lubricants, lubricant-containing polymers with a certain degree of mechanical strength, lubricant supplying ability, and oil retention can be obtained. If some of these relatively low molecular weight polymers are replaced with those classified as waxes, the affinity with lubricants increases due to the small molecular weight difference between the waxes and the lubricants. As a result, the oil retention of the lubricant-containing polymer is improved, enabling the supply of lubricants over a long period of time. However, on the other hand, mechanical strength tends to decrease.

[0024] As the wax, in addition to polyolefin resins such as polyethylene wax, hydrocarbon waxes (for example, paraffin-based synthetic waxes) having a melting point in the range of 100 to 130° C. or higher can be used.

[0025] On the other hand, if an ultra-high molecular weight polymer is used, the difference in molecular weight between the ultra-high molecular weight polymer and the lubricant is large, resulting in a lower affinity with the lubricant, which results in a lower oil retention capacity and faster leaching of the lubricant from the lubricant-containing polymer. This shortens the time it takes for the lubricant-containing polymer to reach the amount of lubricant it can supply, shortening the life of the bearing. However, the mechanical strength is improved.

[0026] Considering the balance of moldability, mechanical strength, oil retention, and lubricant supply amount, the composition ratio of the lubricant-containing polymer is preferably 0 to 5 wt % of a material classified as wax, 8 to 48 wt % of a relatively low molecular weight material, 2 to 15 wt % of an ultra-high molecular weight material, and the total of the three resin components being 10 to 50 wt % (the remainder being 90 to 50 wt % of lubricant).

[0027] As one aspect of mechanical strength, the hardness "HDA" of the lubricant-containing polymer of the present invention is preferably in the range of 65 to 85, more preferably in the range of 70 to 80. If the hardness "HDA" is less than 65, the strength is weak and there is a risk of breakage due to the rotation of the bearing. On the other hand, if the hardness "HDA" exceeds 85, the force restraining the rollers (rolling elements) is large, which may increase the torque of the bearing or increase the heat generated by the rotation of the bearing, resulting in an increase in the temperature of the bearing.

[0028] In order to improve the mechanical strength of the lubricant-containing polymer of the present invention, the following thermoplastic resins and thermosetting resins may be added to the polyolefin resin.

[0029] As the thermoplastic resin, various resins such as polyamide, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, polyether sulfone, polyether ether ketone, polyamide imide, polystyrene, and ABS resin can be used.

[0030] These resins may be used alone or in combination.

[0031] Furthermore, in order to disperse the polyolefin resin and other resins in a more uniform state, an appropriate compatibilizer may be added as necessary.

[0032] To improve the mechanical strength, a filler may be added, such as inorganic whiskers, such as calcium carbonate, magnesium carbonate, potassium titanate whiskers, and aluminum borate whiskers, inorganic fibers, such as glass fibers and metal fibers, and fabrics made from these, or organic compounds, such as carbon black, graphite powder, carbon fibers, aramid fibers, and polyester fibers.

[0033] Furthermore, in order to prevent deterioration of the polyolefin resin due to heat, an antioxidant such as N,N'-diphenyl-p-phenyldiamine or 2,2'-methylenebis(4-ethyl-6-t-butylphenol) may be added, and in order to prevent deterioration due to light, an ultraviolet absorber such as 2-hydroxy-4-n-octoxybenzophenone or 2-(2'-hydroxy-3'-t-butyl-5'-methyl-phenyl)-5-chlorobenzotriazole may be added.

[0034] The amount of all the additives (other than the polyolefin resin and lubricant) added is preferably 20% by weight or less of the total amount of the molding raw material, in order to maintain the supply capacity of the lubricant.

[0035] The polymer materials that can be used in the present invention include those based on the polyolefin resins described above, as well as any thermoplastic resin that can be injection molded, and among these, those that can have a high oil content include, for example, polyester elastomers, etc. In addition to thermoplastic resins, thermosetting resins such as polyurethane and polyurea elastomers can also be used.

[0036] In the case of polyurethane, grease is used as a lubricant, and the reaction raw materials, a urethane prepolymer containing isocyanate groups, and / or an amine-based curing agent, are mixed uniformly into the grease. The two mixtures are then further mixed, filled into a bearing, and heated as necessary to cause a reaction, which is then cured while incorporating the grease.

[0037] On the other hand, in the case of polyurea elastomers, an amine component consisting of a mixture of an aromatic polyamine compound containing soft segments in the molecular chain and an aromatic diamine is uniformly mixed with a lubricating oil compatible with the amine component or a grease based on the lubricating oil, and a polyisocyanate component is further added and mixed to the resulting mixture, which is then filled into a mold of the desired shape and heated as necessary to cause a reaction and cure in a state containing the lubricant.

[0038] The method for molding the lubricant-containing polymer 20 involves first arranging a cylindrical outer mold having an inner peripheral surface large enough to circumscribe the rollers 100, and a cylindrical or columnar inner mold having an outer peripheral surface large enough to inscribe the rollers 100, coaxially and so that they overlap when viewed radially. Then, the rollers 100 are arranged circumferentially between the outer mold and the inner mold, and a raw material for the lubricant-containing polymer 20 that has been heated to a temperature above its melting point and plasticized is poured into the gap formed by the outer mold, inner mold, and rollers 100. The lubricant-containing polymer 20 is then solidified by applying pressure, cooling, or the like. This leaves the solid lubricant-containing polymer 20 holding the rollers 100, and the radial roller bearing 10 is obtained.

[0039] By the above molding, a radial outer slit 25a is formed where the outer die and the roller 100 contact, a radial inner slit 25b is formed where the inner die and the roller 100 contact, and a circumferential slit 25c is formed where adjacent rollers 100 contact each other in the circumferential direction.

[0040] The operation and effects of this embodiment will be described below. As shown in FIG. 2( b), the radial roller bearing 10 is mounted between the housing 200 and the shaft 300. When torque is applied to the radial roller bearing 10 via the shaft 300, the torque is also applied to the rollers 100 via the rolling surfaces of the rollers 100 exposed through the radial outer slits 25a and the radial inner slits 25b. At this time, the lubricant acts between the lubricant-containing polymer 20 and the rollers 100, causing the rollers 100 to roll while maintaining the shape of the lubricant-containing polymer 20. The lubricant-containing polymer 20 also rotates between the housing 200 and the shaft 300 as the rollers 100 roll. At this time, slight deformation of the lubricant-containing polymer 20 may cause the outer peripheral surface 27 or inner peripheral surface 29 of the lubricant-containing polymer 20 to come into contact with the housing 200 or the shaft 300. Even in this case, the lubricant lubricates the outer peripheral surface 27 and inner peripheral surface 29 of the lubricant-containing polymer 20 and the housing 200 or the shaft 300, allowing relative rotation. In this way, the radial roller bearing 10 supports the shaft 300 rotatably relative to the housing 200.

[0041] In conventional radial roller bearings, rollers are prevented from falling out of the cage by being restricted from moving radially inward and outward using a cage or roller fall-off prevention device. According to the configuration of this embodiment, the rollers 100 can be held in place by the lubricant-containing polymer 20, preventing the rollers 100 from falling out without the need for a cage or roller fall-off prevention device, making handling easier. Furthermore, by not using a cage, the rollers 100 can be arranged without gaps in the circumferential direction, resulting in improved load resistance.

[0042] Here, a modification of this embodiment will be described. Figures 5(a) and (b) are cross-sectional views perpendicular to the circumferential direction of a radial roller bearing according to a modification of the first embodiment, with Figure 5(a) showing the radial roller bearing according to the modification of the first embodiment alone, and Figure 5(b) showing the radial roller bearing according to the modification of the first embodiment assembled into a rotary machine. As shown in Figures 5(a) and (b), the radial roller bearing 10 may further include a cage 50 having a plurality of pockets 55 for accommodating a plurality of rollers 100. The cage 50 according to this modification has a pair of coaxially arranged annular portions 51, a plurality of column portions 53 connecting the radial outer portions of the pair of annular portions 51 at a predetermined circumferential interval, and a plurality of pockets 55 formed by the pair of annular portions 51 and circumferentially adjacent column portions 53. Furthermore, the circumferential gap between circumferentially adjacent column portions 53 that form the pocket 55 is smaller than the diameter of the rollers 100. This prevents the rollers 100 housed in the pockets 55 from falling out radially outward from the cage 50 .

[0043] Furthermore, the rollers 100, together with the pair of annular portions 51 and column portions 53, are covered with the lubricant-containing polymer 20 except for portions of the rolling surfaces exposed from the radially outer slits 25 a and the radially inner slits 25 b. That is, the circumferential arrangement of the rollers 100 is maintained by the lubricant-containing polymer 20 and the cage 50. Also in this modified example, the rollers 100 are able to roll between the inner circumferential surface of the housing 200 and the outer circumferential surface of the shaft 300 by receiving torque via the rolling surfaces exposed from the radially outer slits 25 a and the radially inner slits 25 b.

[0044] In this modified example, the pair of annular end portions 21, 21 of the lubricant-containing polymer 20 are formed so as to fill the axial gap between both axial ends of the roller 100 and the annular portion 51 of the cage 50. In addition, the annular end portions 21 cover the radially outer end portion and the radially inner end portion of the annular portion 51 of the cage 50.

[0045] The pillar portions 53 are disposed in the circumferential gaps between circumferentially adjacent rollers 100. Therefore, the axially extending portions 23 of the lubricant-containing polymer 20 are formed to cover the pillar portions 53 in the circumferential gaps between circumferentially adjacent rollers 100, and the axially extending portions 23 that cover the radially outer sides of the pillar portions 53 are formed thin. Furthermore, in this modified example, there is a gap between circumferentially adjacent rollers 100, and all of the rollers 100 do not contact each other. In such a case, the circumferential slits 25c as shown in Figure 2(a) are not formed, and the axially extending portions 23 are formed continuously in the radial direction.

[0046] In this modification, by combining the lubricant-containing polymer 20 with a cage 50 having a simple structure, it is possible to reduce the amount of material used for the lubricant-containing polymer 20 and keep costs down. Also, the strength of the radial roller bearing 10 is improved, making the radial roller bearing 10 less likely to deform even when an external force is applied during transportation, etc. Furthermore, when the radial roller bearing 10 is incorporated into a rotating machine, it becomes easier to restrict the axial movement of the rollers 100.

[0047] Second Embodiment A radial roller bearing according to a second embodiment of the present invention will now be described. Note that some of the description of the same structures as in the first embodiment will be omitted. Fig. 6 is a perspective view of the radial roller bearing according to the second embodiment. Figs. 7(a) and 7(b) are cross-sectional views perpendicular to the circumferential direction of the radial roller bearing according to the second embodiment, with Fig. 7(a) showing the radial roller bearing according to the second embodiment alone and Fig. 7(b) showing the radial roller bearing according to the second embodiment assembled into a rotary machine. Figs. 8(a) and 8(b) are cross-sectional views perpendicular to the circumferential direction of a radial roller bearing according to a modification of the second embodiment, with Fig. 8(a) showing the radial roller bearing according to the modification of the second embodiment alone and Fig. 8(b) showing the radial roller bearing according to the modification of the second embodiment assembled into a rotary machine.

[0048] 6, 7(a) and 7(b), radial roller bearing 10 according to this embodiment comprises outer ring 70, which is a raceway ring having raceway surface 71 on its inner peripheral surface, a plurality of rollers 100 arranged so as to roll freely along raceway surface 71, and lubricant-containing polymer 20 that holds rollers 100. Rollers 100 roll between raceway surface 71 of outer ring 70 and the outer peripheral surface of shaft 300 in the rotary machine.

[0049] As in the first embodiment, the lubricant-containing polymer 20 is formed to extend in the axial direction between circumferentially adjacent axially extending portions 23, and is formed with a plurality of radially outer slits (not shown) and radially inner slits 25b that expose portions of the rolling surfaces of a plurality of rollers 100. In this embodiment, the rolling surfaces of the rollers 100 exposed from the radially outer slits (not shown) come into contact with the raceway surface 71, and the rolling surfaces of the rollers 100 exposed from the radially inner slits 25b come into contact with the outer peripheral surface of the shaft 300.

[0050] The radial roller bearing 10 shown in Figures 6, 7(a) and (b) employs a shell-shaped outer ring obtained by bending and forming a metal plate, but as shown in Figures 8(a) and (b), the outer ring 70 may also be a so-called solid type formed by machining a metal material.

[0051] In this embodiment, with multiple rollers 100 assembled into the outer ring 70, the gap formed between the multiple rollers 100 and the outer ring 70 is filled with raw material of a lubricant-containing polymer 20 that has been plasticized by heating it above its melting point, thereby forming the radial roller bearing 10.

[0052] According to this embodiment, the rollers 100 can be held by the lubricant-containing polymer 20 even on the raceway surface of the outer ring 70, making it possible to improve handling and load resistance.

[0053] The present invention is not limited to the embodiments exemplified above, and modifications can be made as appropriate without departing from the spirit and scope of the present invention. For example, the radial roller bearing 10 is not limited to the one shown in the first embodiment, which does not have raceways such as an outer ring and an inner ring, and in which the rollers 100 roll between the housing 200 and the shaft 300, or the one shown in the second embodiment, which has an outer ring 70 with a raceway surface 71 on its inner circumferential surface, but does not have an inner ring. In other words, the radial roller bearing 10 includes one that has an inner ring with a raceway surface on its outer circumferential surface, but does not have an outer ring. Furthermore, it is also possible for the bearing to have an outer ring and an inner ring.

[0054] Furthermore, the shape of the lubricant-containing polymer 20 need only be such that it can hold the rollers 100 in a rollable manner. For example, the outer peripheral surface 27 and inner peripheral surface 29 of the lubricant-containing polymer 20 need only be formed between the circumscribing circle and the inscribing circle of the rollers 100 in a cross section perpendicular to the axial direction, and need not be arc-shaped in cross section. That is, the outer peripheral surface 27 of the axially extending portion 23 needs only be located slightly radially inward of the circumscribing circle of the rollers 100, exposing the rollers 100 so that a portion of the rolling surface of the rollers 100 faces and comes into contact with the housing 200 or the outer ring 70. Furthermore, the inner peripheral surface 29 of the axially extending portion 23 needs only be located slightly radially outward of the inscribing circle of the rollers 100, exposing the rollers 100 so that a portion of the rolling surface of the rollers 100 faces and comes into contact with the shaft 300 or the inner ring 70.

[0055] Furthermore, the circumferential width Wa of the radially outer slits 25 a and the circumferential width Wb of the radially inner slits 25 b do not have to be constant regardless of the axial position. The cage of the radial roller bearing shown in the modified example of the first embodiment is not limited to the illustrated shape, and may be a so-called comb-shaped cage having a single annular portion in addition to having a pair of annular portions.

[0056] As described above, this specification discloses the following: (1) A radial roller bearing comprising: a plurality of rollers arranged in a circumferential direction and rolling on at least one of the inner peripheral surface of a housing and the outer peripheral surface of a shaft; and a lubricant-containing polymer that holds the plurality of rollers. This configuration makes it possible to provide a radial roller bearing that can prevent the rollers from falling off and improves handleability and load resistance.

[0057] (2) The radial roller bearing according to (1), further comprising a cage having a plurality of pockets for accommodating the rollers, wherein the rollers are held by the lubricant-containing polymer and the cage and roll between the inner peripheral surface of the housing and the outer peripheral surface of the shaft. With this configuration, by holding the rollers with a combination of the cage and the lubricant-containing polymer, the amount of lubricant-containing polymer used can be reduced. Furthermore, the radial roller bearing 10 is less likely to deform even when external forces are applied during transportation, etc. Furthermore, when the radial roller bearing 10 is installed in a rotating machine, it becomes easier to restrict the axial movement of the rollers 100.

[0058] (3) A radial roller bearing according to (1) or (2), further comprising a raceway ring having a raceway surface on its inner or outer peripheral surface, wherein the rollers roll between the raceway surface and the inner peripheral surface of the housing or the outer peripheral surface of the shaft. With this configuration, even in a radial roller bearing having a raceway ring, it is possible to prevent the rollers from falling off, and improve handling properties and load resistance.

[0059] (4) The radial roller bearing according to any one of (1) to (3), characterized in that the lubricant-containing polymer comprises: a pair of annular end portions formed in an annular shape and arranged coaxially so as to abut against both axial end portions of the rollers, a plurality of axially extending portions that axially connect the pair of annular end portions and are formed so as to fill circumferential gaps between circumferentially adjacent rollers, and a plurality of slits that are formed along the axial direction between circumferentially adjacent axially extending portions and expose part of the rolling surfaces of the rollers. With this configuration, the rollers can be held rotatably by the lubricant-containing polymer.

[0060] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0061] This application is based on a Japanese patent application (Patent Application No. 2024-134992) filed on August 13, 2024, the contents of which are incorporated herein by reference.

[0062] REFERENCE SIGNS LIST 10 Radial roller bearing 20 Lubricant-containing polymer 21 Annular end portion 23 Axial extension portion 25a Radially outer slit 25b Radially inner slit 25c Circumferential slit 27 Outer peripheral surface 29 Inner peripheral surface 50 Cage 51 Annular portion 53 Pillar portion 55 Pocket 70 Outer ring (raceway ring) 71 Raceway surface 200 Housing 300 Shaft

Claims

1. A radial roller bearing comprising: a plurality of rollers arranged in a circumferential direction and rolling on at least one of the inner peripheral surface of the housing and the outer peripheral surface of the shaft; and a lubricant-containing polymer that holds the plurality of rollers.

2. A radial roller bearing as set forth in claim 1, further comprising a cage having a plurality of pockets for accommodating said plurality of rollers, said plurality of rollers being held by said lubricant-containing polymer and said cage, and rolling between the inner peripheral surface of said housing and the outer peripheral surface of said shaft.

3. A radial roller bearing as set forth in claim 1, further comprising a bearing ring having a raceway surface on its inner or outer peripheral surface, wherein the rollers roll between the raceway surface and the inner peripheral surface of the housing or the outer peripheral surface of the shaft.

4. A radial roller bearing as claimed in any one of claims 1 to 3, characterized in that the lubricant-containing polymer comprises: a pair of annular end portions formed in an annular shape and arranged coaxially so as to abut both axial end portions of the rollers; a plurality of axially extending portions which connect the pair of annular end portions in the axial direction and are formed so as to fill the circumferential gaps between the circumferentially adjacent rollers; and a plurality of slits formed along the axial direction between the circumferentially adjacent axially extending portions and which expose part of the rolling surfaces of the rollers.

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