Resin-wrapped rolling bearing

Abstract

To provide a resin-wrapped rolling bearing that is formed of only petroleum-derived components, thus is safe for the environment compared to a polyacetal copolymer with 0% of bio-mass degree, prevents slippage between a bearing outer diameter and a housing or a rail and slippage between a bearing inner diameter and a shaft and can prevent excessive rise of a bearing temperature.SOLUTION: A resin-wrapped bearing 1 has a resin-wrapped part on an inner diameter surface 2a of an inner ring 2. The resin-wrapped part 5 is formed of a polyacetal copolymer using biomethanol as a raw material. In the inner ring 2, a contact part with the resin-wrapped part 5 (an inner diameter surface 2a, end surfaces 2b, 2c or an outer diameter surface 2d of the inner ring 2) includes an uneven surface, a chemical conversion-treated surface or an adhesive layer of a phenolic adhesive.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rolling bearing, and more particularly to a resin-wound rolling bearing provided with a resin portion on the inner diameter surface of an inner ring.

Background Art

[0002] Conventionally, in a resin-wound rolling bearing provided with a resin-wound portion on the outer diameter surface of an outer ring, which is used for various guide portions, each time a guide object moves, an intermittent or unstable load is applied to the bearing. Since there is concern that such a load acting on the bearing may affect the bearing life, impact resistance is also required for the resin-wound portion, which is a component constituting the bearing. In addition, there is concern that the resin-wound portion may wear due to creep occurring between the outer ring and the housing, and abnormal noise may occur as the wear progresses, so sliding characteristics of the resin-wound portion are also required. Further, since impact resistance and sliding characteristics are required for the resin-wound portion, polyacetal copolymer has been frequently used as the material of the outer ring resin.

[0003] Further, the rolling bearing of Patent Document 1 is a ball bearing in which rolling elements are interposed between an inner ring and an outer ring, and is a resin-wound rolling bearing provided with an inner resin layer and an outer resin layer that overlap each other inside and outside on the outer periphery of the outer ring. As the resin of the outer resin layer, polyacetal is disclosed as an example of the resin of a petroleum-based resin layer.

[0004] Further, the rolling bearing of Patent Document 2 is a non-metal material-wound rolling bearing in which balls as rolling elements are interposed between an inner ring and an outer ring, and a non-metal material is wound around the outer diameter of the outer ring of the bearing. As an example of the resin of the non-metal material, petroleum-based polyacetal is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, conventional polyacetal copolymers are all derived from petroleum, including methanol as the main raw material, and are not environmentally friendly. In addition, since the polyacetals disclosed in Patent Documents 1 and 2 have the characteristic of high self-lubricity, in the environment of outer ring clearance fit and inner ring interference fit, which are recommended for the installation of inner ring rotating load bearings, in a bearing provided with a resin winding portion on the outer diameter surface of the outer ring, there is a problem that slippage occurs between the outer diameter surface of the bearing and the housing or rail portion, resulting in abnormal noise and vibration.

[0007] Furthermore, a rolling bearing generates heat during rotation, and the temperature of the bearing is kept from becoming too high by dissipating the heat through the housing on the outer diameter side of the outer ring or the shaft on the inner diameter side of the inner ring. In particular, the outer diameter side of the outer ring has a large volume, that is, a large heat capacity, so heat dissipation is also a necessary function. However, since resin has lower thermal conductivity than the metal materials used for the bearing outer ring and housing, there is a concern that providing a resin winding portion on the outer diameter surface of the outer ring may affect heat dissipation.

[0008] The present invention has been made to solve such problems. The methanol, which is the main raw material of the polyacetal copolymer, is replaced with bio-methanol derived from plants, and a resin winding portion is formed of a polyacetal copolymer of biomass plastic that is friendly to the environment. In addition, the present invention forms the resin winding portion on the inner diameter side of the inner ring to prevent the occurrence of the slippage, and the resin winding portion is clamped between the inner ring and the shaft by the inner ring interference fit, so that no slippage occurs between the inner diameter surface of the inner ring and the shaft. Furthermore, since the structure is such that heat conduction to the housing side with a large heat capacity is not hindered by the resin winding portion, the object is to solve the problem that the temperature of the bearing becomes too high.

Means for Solving the Problems

[0009] To achieve this object, a first aspect of the present invention provides a resin-wound rolling bearing having a resin-wound portion on the inner diameter side of an inner ring, wherein the resin-wound portion is formed of a polyacetal copolymer using biomethanol as a raw material, a contact portion between the inner ring and the resin-wound portion is provided with an uneven surface, a phosphating-treated surface, or an adhesive layer of a phenolic adhesive.

[0010] A second aspect of the present invention is the resin-wound rolling bearing according to the first aspect, wherein the contact portion with the resin-wound portion is at least the inner diameter surface, end surface, or outer diameter surface of the inner ring. A third aspect of the present invention is the resin-wound rolling bearing according to the first or second aspect, wherein the bio-degree of the polyacetal copolymer is 90.9 to 99.99%. Since the polyacetal copolymer of the present invention has a bio-degree of 90.9 to 99.99%, it is more environmentally friendly than a conventional polyacetal copolymer having a bio-degree of 0% made only from petroleum-derived components, and it can provide a resin-wound rolling bearing in which slippage between the outer diameter of the bearing and a housing or rail, and slippage between the inner diameter of the bearing and a shaft do not occur, or overheating of the bearing can be prevented.

Advantages of the Invention

[0011] According to the resin-wound rolling bearing of the present invention, compared with a conventional polyacetal copolymer having a bio-degree of 0% made only from petroleum-derived components, it is more environmentally friendly, and slippage between the outer diameter of the bearing and a housing or rail, and slippage between the inner diameter of the bearing and a shaft do not occur, and overheating of the bearing can be prevented. In addition, since the polyacetal copolymer with a high bio-degree of the present invention has an unchanged chemical composition, there is no difference in characteristics such as mechanical properties and heat resistance compared with a polyacetal copolymer manufactured only from conventional petrochemical-derived raw materials. Furthermore, compared with a polyacetal homopolymer, the polyacetal copolymer has high thermal stability due to differences in molecular structure and is excellent in long-term characteristics such as the creep rupture life required for resin-wound rolling bearings.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

[0013] The present invention is a resin wound rolling bearing having a resin wound portion on the inner diameter surface of the inner ring. The resin wound portion is formed of a polyacetal copolymer using biomethanol as a raw material, and an uneven surface, a chemical conversion treated surface, or an adhesive layer of a phenolic adhesive is provided at the contact portion between the inner ring and the resin wound portion.

[0014] Such a resin wound rolling bearing is more environmentally friendly than a polyacetal copolymer made only of petroleum-derived components, and there is no slippage between the outer diameter of the bearing and the housing or rail, and between the inner diameter of the bearing and the shaft. Also, since the resin wound portion does not prevent heat conduction to the housing side with a large heat capacity, it is possible to prevent the temperature of the bearing from becoming too high. In addition, compared with winding resin on the outer diameter surface of the outer ring, winding resin on the inner diameter surface of the inner ring reduces the amount of resin used, resulting in a more environmentally friendly resin wound rolling bearing. Hereinafter, the first to fourth embodiments of the present invention will be described. Note that these embodiments are merely examples of the present invention and are not to be construed as limiting in any way, and design changes can be made as appropriate within the scope of the present invention.

[0015] [First Embodiment] As shown in Fig. 1, the resin-wound rolling bearing 1 of the present embodiment is a ball bearing in which rolling elements 4 are interposed between an inner ring 2 and an outer ring 3. In addition to the shape along the inner diameter surface 2a of the inner ring 2, the contact portions of both end faces 2b and 2c are covered with resin-wound portions 5. Also, in Fig. 1, although the corners at both ends of the resin-wound portion 5 are shown as not being rounded, in actuality, they are chamfered (the same applies to Figs. 2 and 3 below).

[0016] Specifically, a resin-wound portion 5 is formed by winding resin with a predetermined thickness t1 in the radial direction over the entire axial direction of the inner diameter surface 2a of the inner ring 2. Also, the entire surfaces of both end faces 2b and 2c are covered with resin having a predetermined thickness t2 in the radial direction and a predetermined thickness t3 in the axial direction. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0017] The resin-wound portion 5 is a member formed by injection molding (insert molding) a polyacetal copolymer using biomethanol as a raw material. The inner ring 2 is subjected to either chemical conversion surface treatment with a zinc phosphate film or a silane coupling agent, or adhesive layer formation treatment by baking a phenolic adhesive, at the inner diameter surface 2a, which is the contact portion with the resin-wound portion 5, and both end faces 2b and 2c. The zinc phosphate film is formed as a primer layer, and the silane coupling agent improves the adhesion of the adhesive.

[0018] Further, in the present embodiment, methanol is changed to plant-derived biomethanol, and the polyacetal copolymer is changed to be environmentally friendly. Also, by forming the contact portions with the resin-wound portion 5 on the inner diameter surface 2a and both end faces 2b and 2c of the inner ring 2, in applications where the outer diameter of the bearing is used with a clearance fit, slippage between the outer diameter of the bearing and the housing or the rail is less likely to occur, and heat dissipation from the bearing to the housing side is not hindered. This polyacetal copolymer made from biomass plastic using biomethanol as a raw material has a bio-degree of 90.9 to 99.99% based on the usage ratio of biomethanol, and is very environmentally friendly.

[0019] Next, the manufacturing process of the adhesive layer of the resin winding portion 5 will be described. In order to manufacture the polyacetal layer on the inner diameter surface 2a, both end surfaces 2b and 2c of the inner ring 2 by injection molding (insert molding), it is essential to perform chemical conversion treatment such as the inner diameter surface 2a, end surfaces 2b and 2c of the inner ring 2 before insert molding, or zinc phosphate film or silane coupling agent, or to form an adhesive layer such as baking of a phenolic adhesive. The reason is that if these are not formed on the inner diameter surface 2a etc. of the inner ring 2, due to the molding shrinkage of the resin generated during injection molding, problems such as the resin layer peeling off from the inner diameter surface 2a of the inner ring 2 or cracking during demolding will occur.

[0020] In addition to the shape along the inner diameter surface 2a of the inner ring 2, regarding a form different from the shape in which the contact portions of both end surfaces 2b and 2c are covered by the resin winding portion 5, for the outer diameter surface 2d of the inner ring 2, an example of performing a groove or a fine unevenness processing for fixing the injected resin will be described in the third embodiment.

[0021] Also, as the base resin for forming the resin winding portion 5, a polyacetal copolymer of biomass plastic can be used. This polyacetal copolymer is produced by using trioxane (trimer of formaldehyde) obtained from plant-derived biomethanol as the main raw material and adding at least 2 cyclic ethers having adjacent carbon atoms such as ethylene oxide or 1,3-dioxane to trioxane in an amount of 0.1 to 10 mol% and polymerizing.

[0022] From the above addition ratio, the bio-degree (bio ratio) of this polyacetal copolymer is 90.9 to 99.99%. The polyacetal copolymer has higher thermal stability due to the difference in molecular structure compared to the polyacetal homopolymer, and is excellent in long-term characteristics such as the creep rupture life required for resin wound rolling bearings.

[0023] As described above, the molecular weight of the polyacetal copolymer is in the range that can be injection-molded, specifically, the number-average molecular weight is 13,000 to 28,000, and more preferably, considering fatigue resistance and moldability, the number-average molecular weight is in the range of 18,000 to 26,000. When the number-average molecular weight is less than 13,000, the molecular weight is too low, resulting in poor fatigue resistance and low practicality. On the other hand, when the number-average molecular weight exceeds 28,000, the melt viscosity becomes too high, making it difficult to accurately manufacture the resin-wound part by injection molding (insert molding), which is not preferable.

[0024] Such a base resin exhibits a certain level of durability even on its own, works favorably against the wear of the mating member (shaft part) that the resin-wound part may come into contact with, and functions sufficiently as a bearing component. However, when used under more severe operating conditions, it is also assumed that the resin-wound part may be damaged, deformed, or worn. Therefore, in order to further enhance reliability, a reinforcing material may be compounded.

[0025] Moreover, as the reinforcing material, glass fiber, carbon fiber, aramid fiber, potassium titanate whisker, aluminum borate whisker, etc. are preferable, and those surface-treated with a silane coupling agent or the like are more preferable in consideration of the adhesiveness with the polyamide resin listed above. Also, these reinforcing materials can be used in combination of multiple types. Considering the impact strength, it is preferable to compound fibrous materials such as glass fiber and carbon fiber, and further considering the damage to the mating material, it is preferable to compound whisker-like materials in combination with fibrous materials. The mixing ratio in the case of mixed use varies depending on the types of fibrous materials and whisker-like materials, and is appropriately selected in consideration of the impact strength, damage to the mating material, etc.

[0026] In addition, as the glass fiber, in addition to those having a general average fiber diameter of 10 to 13 μm, those having an average fiber diameter of 5 to 7 μm that can enhance strength and improve wear resistance with a small content, or those having a profiled cross-section are more suitable.

[0027] Furthermore, as for carbon fibers, if strength is prioritized, PAN-based carbon fibers are preferable, but pitch-based carbon fibers, which are advantageous in terms of cost, can also be used. As for the average fiber diameter, those with a diameter of 5 to 15 μm are preferable. Since carbon fibers have high strength and modulus of elasticity in the fiber itself, it is possible to increase the strength and modulus of elasticity of the cage compared to glass fibers.

[0028] As for aramid fibers, para-aramid fibers with excellent reinforcement properties can be preferably used. As for the average fiber diameter, those with a diameter of 5 to 15 μm are preferable. Since aramid fibers do not damage steel materials like glass fibers and carbon fibers, they do not deteriorate the surface state of the mating member that the cage contacts. Therefore, when emphasizing the acoustic properties of resin rolling bearings, etc., they are more preferable.

[0029] When incorporating these reinforcing materials, it is preferably blended at a ratio of 10 to 40% by weight, particularly 15 to 30% by weight, of the total. When the blending amount of the reinforcing material is less than 10% by weight, the improvement in mechanical strength is small and not preferable. When the blending amount of the reinforcing material exceeds 40% by weight, the moldability deteriorates, and depending on the type of the reinforcing material, the damageability to the mating material increases, which is not preferable.

[0030] Furthermore, as an additive to the resin, in order to prevent deterioration due to heat during molding and use, it is preferable to add an iodide-based heat stabilizer or an amine-based antioxidant, either alone or in combination.

[0031] In addition, polyacetal has the problem of a large molding shrinkage rate. Specifically, it is 2.0 to 2.5 for polyacetal, compared to 0.8 to 1.5 for polyamide 66 (PA66) and 0.6 to 0.8 for polyphenylene sulfide (PPS). Therefore, when polyacetal is formed by injection molding on the inner ring inner diameter side, there is a risk of coming off from the inner ring inner diameter part during or after removal.

[0032] Therefore, an adhesive layer is formed on the contact portion with the resin winding portion, such as by forming grooves, or processing fine irregularities, performing chemical conversion treatment with a zinc phosphate film or a silane coupling agent, or baking a phenolic adhesive. Regarding this point, in the following Second Embodiment and Third Embodiment, examples in which grooves or fine irregularities are processed on the contact portion with the resin winding portion will be described in detail.

[0033] [Second Embodiment] Figure 2(a) shows the Second Embodiment of the present invention. The resin-wound rolling bearing 1 of this embodiment is a ball bearing in which rolling elements 4 are interposed between an inner ring 2 and an outer ring 3, and only the inner diameter surface 2a of the inner ring 2 is covered with a resin winding portion 5 as a contact portion with the resin winding portion 5. In addition, among the reference numerals attached to FIG. 1, the same reference numerals as those in FIG. 2 are attached as they are, but the shape in which only the inner diameter surface 2a of the inner ring 2 is covered with the resin winding portion 5 as a contact portion with the resin winding portion 5 is different from that of the First Embodiment, and the description of the same constituent members is omitted.

[0034] In this way, since the structure is such that the heat conduction to the housing side with a large heat capacity is not hindered by the resin winding portion 5, the problem that the temperature of the bearing becomes too high can also be solved. In addition, compared with the resin winding on the outer diameter surface of the outer ring 3, the resin winding on the inner diameter surface of the inner ring 2 can provide a more environmentally friendly resin-wound rolling bearing with a reduced amount of resin used.

[0035] Furthermore, as shown in FIGS. 2(b) and 2(c), similar to the First Embodiment, by covering and forming the inner diameter surface 2a side with a resin winding portion, the occurrence of slippage is prevented, and the resin winding portion 5 is clamped between the inner ring 2 and the shaft by the inner ring shrink fit, so that no slippage occurs between the inner diameter surface 2a of the inner ring 2 and the shaft. In addition, since the structure is such that the heat conduction to the housing side with a large heat capacity is not hindered by the resin winding portion 5, it is also possible to solve the problem that the temperature of the bearing becomes too high.

[0036] Further, the resin-wound portion 5 is a member formed by injection molding (insert molding) a polyacetal copolymer using biomethanol as a raw material. At the contact portion between the inner ring 2 and the resin-wound portion 5, the resin winding is subjected to either chemical conversion surface treatment with a zinc phosphate film or a silane coupling agent, or adhesive layer formation treatment by baking a phenolic adhesive.

[0037] Figure 2(a) shows a shape in which the contact portion with the resin-wound portion 5 only covers the inner diameter surface 2a of the inner ring 2. Specifically, the entire axial direction of the inner diameter surface 2a of the inner ring 2 is formed with a resin-wound portion 5 by resin winding with a predetermined thickness t1 in the radial direction. Compared with the first embodiment in FIG. 1, the resin-wound portion 5 does not cover the end faces 2b and 2c. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0038] Figure 2(b) shows a shape in which the contact portion with the resin-wound portion 5 covers a part of the inner diameter surface 2a and the end faces 2b and 2c of the inner ring 2. Specifically, the entire axial direction of the inner diameter surface 2a of the inner ring 2 is resin-wound with a predetermined thickness t1 in the radial direction to form a resin-wound portion 5, and a part of both end faces 2b and 2c (about half in FIG. 2(b)) is covered with a predetermined thickness t3 in the axial direction as shown in FIG. 1, and further, a resin-wound portion 5 by resin winding with a predetermined thickness t4 in the radial direction is formed as shown in FIG. 2(b).

[0039] This resin-wound portion 5 has a configuration in which, like the resin-wound portion 5 of the first embodiment in FIG. 1, it covers not all of the end faces 2b and 2c but a part on the inner diameter side. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like. In this way, even if only a part on the inner diameter side is covered instead of all of the end faces 2b and 2c, the contact portion adhesive surface with the resin-wound portion 5 becomes larger, so that the adhesion of the resin-wound portion 5 to the bearing becomes stronger against vibration of the bearing.

[0040] Figure 2(c) shows a shape in which the contact portion with the resin winding portion 5 covers a part of the inner diameter surface 2a, end surfaces 2b and 2c, and the outer diameter surface 2d of the inner ring 2. Specifically, as shown in Figure 1, the entire axial direction of the inner diameter surface 2a of the inner ring 2 is resin-wound with a predetermined thickness t1 in the radial direction, and the entire both end surfaces 2b and 2c are covered with resin having a predetermined thickness t5 in the radial direction with a predetermined thickness t3 in the axial direction, and further covered with resin having a predetermined thickness t6 in the axial direction on the outer diameter surface 2d side. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like. In this way, by covering the outer diameter surface 2d side with resin having a predetermined thickness t6 in the axial direction, the adhesion surface with the contact portion with the resin winding portion 5 becomes larger, so that even if there is vibration in the bearing, the adhesion of the resin winding portion 5 becomes stronger.

[0041] [Third Embodiment] Figures 3(a) to (e) each show the third embodiment of the present invention. The resin-wound rolling bearing 1 of this embodiment is a ball bearing in which rolling elements 4 are interposed between an inner ring 2 and an outer ring 3, and the inner diameter surface 2a, end surfaces 2b and 2c, and outer diameter surface 2d of the inner ring 2 are covered with a resin winding portion 5 as a contact portion with the resin winding portion 5, and various uneven surface processing treatments such as a thin and thick uneven surface are applied to the resin winding portion 5 on the inner diameter surface 2a side.

[0042] In the reference numerals attached to Figure 3, the same reference numerals as those in Figures 1 and 2 are attached as they are, and the description of the same components is omitted. Also, for the reference numerals 2a, 2b, 2c, and 2d, their descriptions are omitted for easy understanding of the figure. The third embodiment, as shown in Figure 1, not only covers only the inner diameter surface 2a of the inner ring 2 as a contact portion with the resin winding portion 5 with the resin winding portion 5, but also the shape of the resin winding portion 5 is processed and different. Specifically, surface processing such as unevenness is performed on the inner diameter surface 2a which is the contact portion of the inner ring 2 with the resin winding portion 5.

[0043] In this way, since the structure is such that heat conduction to the housing side with a large heat capacity is not hindered by the resin winding portion, the problem of the bearing temperature becoming too high can also be solved. In addition, compared with resin winding on the outer diameter surface of the outer ring, resin winding on the inner diameter surface of the inner ring can provide a more environmentally friendly resin-wound rolling bearing with a reduced resin usage amount.

[0044] Furthermore, by performing various surface treatment processes such as surface processing of unevenness on the inner diameter surface 2a side and forming the resin winding portion in various shapes on the inner diameter side of the inner ring, the occurrence of slippage is prevented, and due to the resin winding portion being interference-fitted between the inner ring and the shaft, a structure is achieved in which slippage does not occur between the inner diameter surface of the inner ring and the shaft. Also, since the structure is such that heat conduction to the housing side with a large heat capacity is not hindered by the resin winding portion, the problem of the bearing temperature becoming too high can also be solved.

[0045] Also, the resin winding portion 5 is a member formed by injection molding (insert molding) of a polyacetal copolymer using biomethanol as a raw material, and at the contact portion between the inner ring 2 and the resin winding portion 5, the resin winding is subjected to either chemical conversion surface treatment with zinc phosphate film or silane coupling agent, or adhesive layer formation treatment by baking a phenolic adhesive.

[0046] Figure 3(a) shows that the shape of the contact portion with the resin winding portion 5 on the inner diameter side of the inner ring 2 is not a shape along the inner diameter surface 2a of the inner ring 2 but a flange structure in cross-section view. Specifically, resin winding is performed with a predetermined thickness t1 in the radial direction over the entire axial direction of the inner diameter surface 2a of the inner ring 2, the entire both end surfaces 2b, 2c are covered with a predetermined thickness t3 in the axial direction, and also covered with resin having a predetermined thickness t2 in the radial direction, and an L-shaped flange with one axial side protruding is provided, where the radial thickness is formed from a surface with a predetermined thickness (height) t1 on the right side toward the drawing to a predetermined thickness (height) t7 in the radial direction. Note that the formation position of the flange may be reversed left and right. These predetermined thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0047] Figure 3(b) shows that the shape of the contact portion with the resin winding part 5 on the inner diameter side of the inner ring 2 is a tapered structure in cross-section with an inclination instead of a stepped shape as shown in Figure 3(a). Specifically, the inner diameter surface 2a of the inner ring 2 is resin-wound with a predetermined thickness t1 in the radial direction throughout the axial direction, the entire both end surfaces 2b and 2c are covered with a predetermined thickness t3 in the axial direction, and it is covered with a resin such that the inclination gradually increases (the wall thickness increases) from a predetermined thickness (height) t1 to a predetermined thickness (height) t8 in the radial direction. In Figure 3(b), it is covered with a resin such that the inclination increases from t2 on the left side to t8 on the right side in the radial direction toward the drawing, but it doesn't matter if it is reversed left and right. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0048] Figure 3(c) shows that the shape of the contact portion with the resin winding part 5 on the inner diameter side of the inner ring 2 is not a shape with a step on one side as in Figure 3(a) or a tapered shape as in Figure 3(b), but a U-groove structure in cross-section with a semicircular groove provided in the center. Specifically, a resin-wound resin winding part 5 with a U-groove structure in cross-section is formed, where the bottom part of the inner diameter surface 2a of the inner ring 2 has a predetermined thickness (height) t1 and both ends have a predetermined thickness (height) t9. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0049] Figure 3(d) shows that the shape of the contact portion with the resin winding part 5 on the inner diameter side of the inner ring 2 is not a shape with a U-groove structure in cross-section as in Figure 3(c), but a V-groove structure in cross-section with an acute-angle groove provided in the center. Specifically, a resin-wound resin winding part 5 with a V-groove structure in cross-section is formed, where the bottom part of the inner diameter surface 2a of the inner ring 2 has a predetermined thickness (height) t1 and both ends have a predetermined thickness (height) t10. These thicknesses are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0050] Figure 3(e) shows that the shape of the contact portion with the resin winding portion 5 on the inner diameter side of the inner ring 2 is not a simple shape as shown in FIGS. 3(a) to 3(d), but a special shape with many concavities and convexities in cross-section. Specifically, the resin winding portion 5 is formed by resin winding with a predetermined thickness (height) t11 of the convex portion protruding in the radial direction over the entire axial direction from a predetermined thickness (height) t1 of the concave portion on the inner diameter surface 2a of the inner ring 2. Further, in FIG. 3(e), four convex portions with a semi-circular rounded shape are formed, but the number of these convex portions and the thicknesses of these concavities and convexities are appropriately determined according to the size of the resin-wound rolling bearing 1 and the like.

[0051] [Fourth Embodiment] The fourth embodiment is a resin-wound rolling bearing 1 that combines the examples of the second and third embodiments, although not shown in the figures. Specifically, the resin winding portion 5 in FIGS. 3(a) to (e) of the third embodiment is an example of a combination with the resin winding portion 5 in FIG. 2(b) of the second embodiment, and is an example of a combination of the resin winding portion 5 in FIG. 2(a) of the second embodiment and the resin winding portion 5 in FIGS. 3(a) to (e) of the third embodiment.

[0052] It is also an example of a combination of the resin winding portion 5 in FIG. 2(c) of the second embodiment and the resin winding portion 5 in FIGS. 3(a) to (e) of the third embodiment. Since the same configurations of the second and third embodiments are used, the description here is omitted. By making such a combination example, the synergistic effects of the second and third embodiments can be obtained.

Explanation of Reference Numerals

[0053] 1 Resin-wound rolling bearing 2 Inner ring 2a Inner diameter surface 2b, 2c End faces 2d Outer diameter surface 3 Outer ring 4 Rolling element 5 Resin winding portion

Claims

1. In a resin-wound rolling bearing having a resin-wound portion on the inner diameter side of the inner ring, the resin-wound portion is formed of a polyacetal copolymer using biomethanol as a raw material, A resin-wound rolling bearing, characterized in that an uneven surface, a phosphating treatment surface, or an adhesive layer of a phenolic adhesive is provided at a contact portion between the inner ring and the resin-wound portion.

2. The resin-wound rolling bearing according to claim 1, wherein the contact portion with the resin-wound portion is at least the inner diameter surface, end surface, or outer diameter surface of the inner ring.

3. The resin-wound rolling bearing according to claim 1 or 2, characterized in that the bio-degree of the polyacetal copolymer is 90.9 to 99.99%.

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