Rolling shaft receiving cage and rolling bearing

Abstract

To provide a retainer for a rolling bearing which is a retainer in which a protrusion (a protruding part) of a resin is formed at each weld part and yet can inhibit increase of friction and torque during operation of the bearing, and to provide a rolling bearing.SOLUTION: A retainer 1 includes: an annular part 2; and multiple column parts 3 extending from the annular part 2 to one axial side. A rolling element is held in a circumferential space between the column parts 3. The annular part 2 and the column parts 3 are integrally formed by injection molding and at least the annular part 2 has weld parts W. Protruding parts 5 protruding in an axial direction are formed at the axial end side of the annular part 2 where the weld parts W are formed. When an axial dimension of the protruding part 5 is referred to as H and an axial thickness of the annular part 2 in a portion where the protruding part 5 is not formed is referred to as T, (H×100 / T)<6.5% is satisfied.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a rolling bearing cage and a rolling bearing, and particularly to a rolling bearing cage and a rolling bearing used for supporting a rotating member that rotates at high speed, such as the main shaft of a machine tool.

Background Art

[0002] A rolling bearing arranges rolling elements such as balls and cylindrical rollers in an orbital space between an inner ring and an outer ring, and holds these rolling elements by a cage. Conventionally, metal materials such as iron and high-strength brass have been used for the cage of the bearing. However, from the viewpoints of extending the life and reducing the weight of the bearing, the cage is being made of a resin material.

[0003] For example, a combined angular ball bearing or a cylindrical roller bearing is widely used for a bearing that supports the main shaft of a machine tool. Patent Document 1 describes a resin cage used for a cylindrical roller bearing. This resin cage is a cage including one annular portion, a plurality of column portions, and a plurality of pockets formed between the column portions adjacent in the circumferential direction, and is a so-called comb-type cage.

[0004] Further, Patent Document 2 describes a method of manufacturing a cage having a shape with an annular portion and column portions (see also FIG. 1) by injection molding using a resin material. Specifically, it is described that the molten resin injected into the cavity flows in two flows on both sides in the circumferential direction in the cavity, rejoins again at a position opposite to the gate in the radial direction, and is joined to each other to form a weld portion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, in the resin cage formed by injection molding, molten resin is injected from the gate, and a weld portion is formed at the position where the flowing molten resin collides. Here, depending on the resin composition and molding conditions, a raised portion of the resin (hereinafter also referred to as a convex portion) may be formed in the weld portion. In addition, the cage may be in sliding contact with mating members such as rolling elements and raceway rings during bearing rotation. If a raised portion of the resin is formed at such a sliding contact portion, there is a concern that it may lead to an increase in friction, an increase in torque, heat generation, etc.

[0007] The present invention has been made to address such circumstances, and an object thereof is to provide a rolling bearing cage and a rolling bearing that can suppress an increase in friction and an increase in torque during bearing operation even in a cage in which a raised portion (convex portion) of resin is formed in the weld portion.

Means for Solving the Problems

[0008] The rolling bearing cage of the present invention has an annular portion and a plurality of column portions extending axially in one direction from the annular portion, and is a rolling bearing cage that holds rolling elements between the circumferential directions of the column portions, wherein the rolling bearing cage is integrally formed by injection molding of the annular portion and the column portions, has at least a weld portion in the annular portion, and a convex portion that bulges axially is formed on the axial end side of the annular portion where the weld portion is formed.

[0009] When the axial dimension of the convex portion is H and the axial thickness of the annular portion at the location where the convex portion is not formed is T, it is characterized by satisfying (H × 100 / T) < 6.5%.

[0010] It is characterized in that the weld portion is formed so as to extend axially from the annular portion to the column portion.

[0011] In the above-mentioned rolling bearing cage, a plurality of convex portions are formed at equal intervals in the circumferential direction.

[0012] The number of the convex portions is half the number of the column portions.

[0013] The above-mentioned rolling bearing cage is a fork-shaped cage, and extrusion pin marks are formed on the end side opposite to the axial end side where the convex portions are formed.

[0014] The above-mentioned rolling bearing cage is characterized in that it uses polyetheretherketone (PEEK) resin as the base resin and contains a fiber reinforcing agent.

[0015] The rolling bearing of the present invention is a rolling bearing including an inner ring, an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling elements, wherein the cage is the rolling bearing cage of the present invention.

[0016] The above-mentioned rolling bearing is a double-row cylindrical roller bearing, and has a pair of fork-shaped cages that are separated by left and right rows as the cages, and the convex portions are formed on the mating surfaces of these cages.

Advantages of the Invention

[0017] The rolling bearing cage of the present invention has at least a welded portion in the annular portion, and convex portions that bulge axially are formed on the axial end side of the annular portion where the welded portion is formed. Therefore, for example, considering the position of the convex portions in the welded portion, the sliding form of the cage can be selected, so that an increase in friction and an increase in torque during bearing operation in the cage can be suppressed.

[0018] When the axial dimension of the convex portion is H and the axial thickness of the annular portion at the location where the convex portion is not formed is T, (H×100 / T)<6.5% is satisfied, so that even when the sliding form of the cage is a form of sliding contact with the mating member on the axial end side of the annular portion, an increase in friction and an increase in torque during bearing operation can be preferably suppressed.

[0019] Since the welded portion is formed to extend axially from the annular portion to the columnar portion, the strength of the welded portion can be ensured.

[0020] In the above-mentioned rolling bearing cage for a rolling shaft, since a plurality of convex portions are formed at equal intervals in the circumferential direction, excellent rotational stability can be obtained.

[0021] The rolling bearing of the present invention is a rolling bearing provided with the rolling bearing cage of the present invention. In particular, the rolling bearing is a double-row cylindrical roller bearing, and has a pair of comb-shaped cages that are separated into left and right rows as cages. Since convex portions are formed on the mating surfaces of these cages, an increase in friction and an increase in torque during bearing operation can be suppressed.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0023] An example of the rolling bearing cage for a rolling bearing of the present invention will be described with reference to FIG. 1. FIG. 1 is a perspective view of a comb-shaped cage for a cylindrical roller bearing. Note that the rolling bearing cage for a rolling bearing of the present invention is an annular member, and the direction parallel to the central axis of the cage is referred to as the "axial direction", the direction perpendicular to the central axis is referred to as the "radial direction", and the direction around the axis centered on the central axis is referred to as the "circumferential direction".

[0024] The cage 1 shown in Fig. 1 includes an annular portion 2, a plurality (for example, an even number) of column portions 3 extending axially in one direction from the inner surface 2a of the annular portion 2, and a plurality of pocket portions 4 formed between the circumferential side surfaces of the column portions 3 adjacent in the circumferential direction for rotatably holding cylindrical rollers. The cage 1 is an injection molded body using a resin material, and the annular portion 2 and the column portions 3 are integrally formed.

[0025] Here, when manufacturing a cage as shown in Fig. 1 by injection molding, a weld portion is formed in a region where the molten resin converges during injection molding. In the rolling bearing cage of the present invention, a weld portion is formed at least in the annular portion, and by controlling the position and dimensions of the resin swelling portion (protrusion) due to the formation of the weld portion, an increase in friction and the like are suppressed. This protrusion will be described with reference to Fig. 2.

[0026] Fig. 2 shows a view of the cage of Fig. 1 as seen from the radially outer side. In Fig. 2, a weld portion W is formed in the portion surrounded by the dotted line. That is, in the cage 1, the weld portion W is formed in the annular portion 2 and the column portions 3. More specifically, the weld portion W is formed so as to extend axially from the annular portion 2 to the column portions 3. Further, in the column portion 3, the weld portion W is located at substantially the center in the circumferential direction of the column portion 3. By forming the weld portion W also in the column portion 3, the area of the weld portion becomes larger compared to the case where it is formed only in the annular portion 2, and the strength of the weld portion can be ensured.

[0027] In the retainer 1, a convex portion 5 that bulges axially is formed on the axially end side of the annular portion 2 where the weld portion W is formed. The convex portion 5 is formed by the resin bulging when the molten resin converges during injection molding, and is formed in a curved shape that bulges axially. In FIG. 2, the convex portion 5 is formed only on the outer surface 2b of the annular portion 2. On the other hand, on the outer diameter surface of the retainer 1 (including the outer diameter surface 2c of the annular portion 2 and the outer diameter surface of the column portion 3) and the inner diameter surface of the retainer 1, no convex portion is formed due to the bulging of the resin, and it is in an annular shape. Also, no convex portion is formed on the tip surface of the column portion 3 due to the bulging of the resin. Note that on the outer surface 2b of the retainer 1, a weld line is formed linearly toward the axis center. Thus, in the rolling bearing retainer of the present invention, the position of the convex portion in the weld portion is limited.

[0028] In the rolling bearing retainer of the present invention, the circumferential position of the retainer where the weld portion is formed and the circumferential position of the retainer where the convex portion is formed coincide. Also, the number of weld portions and the number of convex portions are the same.

[0029] Furthermore, by controlling the height (axial dimension) of the convex portion 5, as shown in FIG. 4 described later, even when the outer surface 2b is in sliding contact with the mating member, it is possible to suppress an increase in friction, an increase in torque, heat generation, etc. Specifically, when the axial dimension of the convex portion 5 is H and the axial thickness dimension of the annular portion 2 at the location where the convex portion 5 is not formed is T, it is preferable to satisfy (H × 100 / T) < 6.5%. If (H × 100 / T) exceeds 6.5%, the protruding ratio of the convex portion becomes large, which may be disadvantageous in terms of an increase in friction, an increase in torque, heat generation, etc. Note that the axial dimension H of the convex portion 5 is the difference between the axial dimension of the portion where the convex portion 5 bulges most axially on the outer surface 2b and the axial dimension of the portion where the convex portion is not formed.

[0030] Further, the convex portion 5 exists on the outer surface 2b from the outer diameter side to the inner diameter side of the cage 1, and the axial dimension near the outer diameter side of the convex portion 5 and the axial dimension near the inner diameter side of the convex portion 5 are substantially the same. It is preferable that the convex portion 5 uniformly exists with substantially the same dimension from the outer diameter side to the inner diameter side because it is less likely to wear. In the present invention, a portion where (H×100 / T) is greater than 0.5% is defined as a convex portion. (H×100 / T) is more preferably 2.0% or more and less than 6.5%, and even more preferably 3.5% or more and less than 5.0%.

[0031] In the cage for a rolling bearing of the present invention, the number of convex portions is not particularly limited, but it is preferable to form a plurality of them. In particular, in the form where a plurality of convex portions are formed, the convex portions are preferably formed at equal intervals in the circumferential direction. By arranging the convex portions equally, rotational stability is easily obtained.

[0032] In the cage 1 shown in FIG. 2, the number of convex portions 5 (the number of welded portions W) is set to half the number of column portions 3. For example, the number of column portions 3 is 28, while the number of convex portions 5 is set to 14. Further, in the cage 1 of FIG. 2, the column portions with the welded portions W formed and the column portions without the welded portions W are alternately arranged in the circumferential direction. That is, the welded portions W are formed in every other column portion 3 in the circumferential direction.

[0033] Subsequently, FIG. 3 shows a view of the cage of FIG. 1 as seen from one axial side (the tip side of the column portion). That is, it shows the side opposite to the axial end side where the convex portion is formed. As shown in FIG. 3, the opposing pocket inner surfaces 3a of the column portions 3 adjacent to each other in the circumferential direction of the annular portion 2 are recessed in a shape along the circumferential surface of the cylindrical roller 7, and the shape of the pocket is cylindrical so that the cylindrical roller 7 can fit in. Further, a groove-shaped lubricant reservoir portion 3b and a notch portion 3c are provided on the pocket inner surface 3a of the column portion 3. The notch portion 3c is formed on the axial end side on the inner diameter side of the column portion 3 and serves to promote the inflow of lubricant from the outside into the pocket.

[0034] As shown in Fig. 3, an extrusion pin mark 6 is formed on the end side opposite to the axial end side where the above-described convex portion is formed. Specifically, the extrusion pin mark 6 is formed on the tip surface 3d of the column portion 3 extending in one axial direction. The extrusion pin mark 6 is formed by pressing an extrusion pin when taking out the molded body from the injection mold. For example, the extrusion pin mark 6 is formed in a concave shape slightly recessed from the tip surface (axial end surface) of the column portion 3 on the surface of the tip surface, and its presence or absence can be confirmed visually. In the column portion 3, the extrusion pin mark 6 is located at substantially the center in the circumferential direction of the column portion 3.

[0035] When the extrusion pin mark is formed on the surface that slidably contacts the mating member (for example, the inner surface of the pocket or the inner surface of the annular portion), friction increase or the like may occur due to the roughness of the extrusion pin mark. Therefore, as shown in Fig. 3, by forming the extrusion pin mark 6 on the tip surface 3d of the column portion 3, it is possible to suppress friction increase or the like caused by the extrusion pin mark 6.

[0036] Here, when the diameter dimension of the extrusion pin mark 6 is D and the minimum wall thickness in the circumferential direction of the column portion 3 is A, it is preferable to satisfy 0.10 < (D / A) < 0.90. If (D / A) is less than 0.10, the area of the extrusion pin is small and the pressure becomes high, so the formed extrusion pin mark becomes deep, and for example, the column portion 3 may be deformed. Also, if (D / A) is greater than 0.90, there is a possibility of interference with the mold.

[0037] Here, in the present invention, the minimum wall thickness in the circumferential direction of the column portion means the minimum value of the distance between the side surfaces of the column portion facing the pocket. In Fig. 3, the axial end (front side in the figure) of the column portion 3 is formed such that the distance between the side surfaces (the wall thickness in the circumferential direction of the column portion) gradually or continuously decreases from the outer diameter side to the inner diameter side, and the inner diameter side end portion is the minimum wall thickness portion in the circumferential direction. In this case, the thickness of the axial end portion on the inner diameter side of the column portion 3 is dimension A.

[0038] On the other hand, as shown in FIG. 3, when the extrusion pin mark 6 is circular, the diameter dimension D of the extrusion pin mark is its diameter. Note that the shape of the extrusion pin mark corresponds to the shape of the axial cross-section of the tip of the extrusion pin, and is not limited to the circular shape in FIG. 3, and other shapes may also be used. For example, it may be a polygonal shape such as a triangle, a quadrilateral, or a pentagon. When the extrusion pin mark is a substantially regular polygon, the diameter of the circle passing through all the vertices may be used as the diameter dimension D of the extrusion pin mark.

[0039] The value of (D / A) may be 0.50 < (D / A) < 0.90, may be 0.60 < (D / A) < 0.90, or may be 0.60 < (D / A) < 0.80. Also, it may be 0.10 < (D / A) < 0.50, may be 0.10 < (D / A) < 0.40, or may be 0.10 < (D / A) < 0.30.

[0040] As shown in FIG. 3, it is preferable that a plurality of extrusion pin marks 6 are formed. In a form in which a plurality of extrusion pin marks 6 are formed, it is more preferable that the extrusion pin marks 6 are formed (equally spaced) at equal intervals in the circumferential direction. Thereby, when taking out the molded body from the injection mold, a force can be evenly applied by a plurality of extrusion pins, extrusion can be stably performed, and deformation of the holder can be suppressed. Also, in FIG. 3, the extrusion pin marks 6 are formed on the tip surfaces 3d of all the column portions 3, respectively.

[0041] Also, in terms of the positional relationship with the weld portion, it is preferable that the extrusion pin mark 6 is formed so as to cover the weld portion formed at the axial end portion. In FIG. 3, the weld portion is formed axially including, for example, the axial end portions of every other column portion 3, and the extrusion pin marks 6 are formed so as to cover the axial end portions of all those weld portions. Extruding from above the weld portion with an extrusion pin during extrusion is advantageous from the viewpoint of deformation of the molded body. Further, it is more preferable that the approximate center of the extrusion pin mark 6 is at the weld portion (which may be a weld line) so that the left and right sides of the weld portion can be extruded substantially evenly.

[0042] Fig. 4 shows a double-row cylindrical roller bearing as an example of a cylindrical roller bearing to which the above-described cage for a cylindrical roller bearing is applied. The double-row cylindrical roller bearing 11 includes an inner ring 12, an outer ring 13, a plurality of cylindrical rollers 14, 14 interposed between the inner ring 12 and the outer ring 13 and arranged in two rows spaced apart in the axial direction, and the above-described two cages 1, 1. The inner ring 12 is a double-row raceway ring provided with a middle flange at the central portion in the axial direction and outer flanges at the end portions on both sides in the axial direction. The two cages 1, 1 are arranged such that their annular portions 2, 2 are adjacent to each other, and the cylindrical rollers 14, 14 in each row are held at regular intervals in the circumferential direction by their respective pocket portions 4, 4. If necessary, lubricants such as grease are enclosed around the cylindrical rollers 14, 14 for lubrication. For example, a main shaft of a machine tool or the like is fitted into the inner ring 12, and the outer ring 13 is fitted into a housing or the like, so that the double-row cylindrical roller bearing 11 supports the main shaft in a rotatable state.

[0043] As shown in Fig. 4, in the double-row cylindrical roller bearing 11, the cages 1, 1 are arranged with the axial end faces of the annular portions 2, 2 facing each other (the backs of the cages 1, 1 facing each other). The cages 1, 1 are a pair of comb-shaped cages that are separate for the left and right rows, and when the bearing rotates, the backs of the cages 1, 1 are in sliding contact with each other. Even in such a sliding form of the cage, by controlling the position and dimensions of the convex portions as described above, it is possible to suppress an increase in friction due to the sliding contact of the cages 1, 1.

[0044] Further, by using a cage in which a plurality of convex portions are provided at equal intervals in the circumferential direction as shown in Fig. 2 as the cage, for example, it is possible to arrange or rotate the cage such that a portion where the convex portion of one cage is formed and a portion where the convex portion of the other cage is not formed face each other, and it is considered that stable rotation can be realized.

[0045] In FIGS. 1 to 4 above, as the rolling bearing cage of the present invention, a cage for a cylindrical roller bearing was exemplified. However, resin cages such as a crowned cage used for a ball bearing are also annular molded bodies, and a weld portion is formed in a part thereof, and the present invention can be applied. Furthermore, as long as the cage has a weld portion at the time of injection molding, the present invention can be applied to any other ball bearing, cylindrical roller bearing, tapered roller bearing, or needle roller bearing.

[0046] The rolling bearing cage of the present invention is a resin cage formed by injection molding a resin material. The mold for manufacturing the resin cage in the case of injection molding is composed of a fixed mold (the mold on the fixed side) and a movable mold (the mold on the movable side) that can be clamped and opened with respect to the fixed mold. By injecting and filling the molten resin from the gate into the molding cavity formed by the clamped fixed mold and movable mold and solidifying it, a cage corresponding to the shape of the molding cavity is molded. The type, position, and number of gates can be set as appropriate.

[0047] For example, gates such as tunnel gates can be arranged at every other position in the circumferential direction of the cavity portion for molding the inner diameter portion of the column portion. In this case, gate traces are formed on the inner diameter surface 3e (see FIG. 3) of every other column portion 3 in the circumferential direction of the cage. By arranging in this way, weld portions are formed in every other column portion.

[0048] FIG. 5 shows a schematic diagram of an injection molding die. As the resin material for the cage during injection molding, molding pellets obtained by blending and kneading a fiber reinforcing agent and the like in a base resin in a predetermined amount are used. These molding pellets are put into the hopper 22 of the injection molding machine 21 and introduced from the hopper 22 into the cylinder 23. Thereafter, the molding pellets are heated and melted by the heater 24 in the cylinder 23 while being pushed by the screw 25, pass through the metering section, and are filled as the molten resin for one shot of the molded product toward the cylinder nozzle 26 side. From this cylinder nozzle 26, the molten resin is injected and filled into the cavity of the desired cage shape (for example, the shape in FIG. 1) in the mold 27 through the gate 27a to perform molding.

[0049] After molding, the fixed mold and the movable mold are opened, and for example, by advancing a plurality of ejector pins 28 against the molded body, the molded body is taken out. By these ejector pins 28, ejector pin marks 6 (see FIG. 3) are formed on the cage. The diameter dimension of the tip of the ejector pin 28 can be set in consideration of the shape of the cage, for example, so as to satisfy the above-described relational expression of (D / A).

[0050] The base resin of the resin material of the cage for rolling bearings of the present invention can be injection-molded, and any resin can be used as long as it has sufficient heat resistance and mechanical strength as a cage material. Examples of the synthetic resin serving as the base resin include polyamide (PA) resins such as polyamide 6 (PA6) resin, polyamide 6-6 (PA66) resin, and polyamide 4-6 (PA46) resin, PEEK resin, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin, ethylene-tetrafluoroethylene copolymer (ETFE) resin and other fluororesins that can be injection-molded, polyethylene (PE) resins such as low-density polyethylene, high-density polyethylene, and ultra-high molecular weight polyethylene, polycarbonate (PC) resin, polyacetal (POM) resin, wholly aromatic polyester resin, polysulfide (PPS) resin, polyamideimide (PAI) resin, polyetherimide (PEI) resin, injection-moldable polyimide (PI) resin, and the like. In each polyamide resin, the numbers represent the number of carbon atoms between amide bonds. These synthetic resins may be used alone or may be a polymer alloy mixed with two or more of them.

[0051] Among these, since they are excellent in mechanical strength, rigidity, heat resistance, etc., it is preferable to use at least one of PEEK resin, PA resin, and PPS resin as the base resin, and it is more preferable to use PEEK resin. PEEK resin is a crystalline thermoplastic resin having a polymer structure in which benzene rings are connected at the para positions by carbonyl groups and ether bonds.

[0052] Here, when using a PEEK resin with relatively high viscosity, if the number of gates for pouring the molten resin is small, the strength of the welded part may become weak. Therefore, when using a PEEK resin, it is preferable to increase the number of gates compared to the case of using a PA resin (for example, PA66 resin). As a result, a cage using a PEEK resin as the base resin tends to have a large number of welded parts. For example, in a cage using a PEEK resin as the base resin, the number of welded parts is more than half of the number of column parts.

[0053] In addition, in order to improve the mechanical strength such as the elastic modulus of the above resin material, it is preferable to blend fiber reinforcing agents such as carbon fiber, glass fiber, aramid fiber, boron fiber, and various mineral fibers (whiskers) within a range that does not inhibit the injection moldability. As the fiber reinforcing agent, it is more preferable to blend glass fiber or carbon fiber because of its excellent reinforcing effect and availability.

[0054] The blending amount of the fiber reinforcing agent is preferably 10% by mass to 50% by mass, and more preferably 10% by mass to 40% by mass based on the entire resin material. By setting it within the above range, it becomes easier to improve the mechanical strength of the cage while ensuring the fluidity of the molten resin.

[0055] Additives other than the fiber reinforcing agent can be blended in the above resin material within a range that does not impair the function and injection moldability of the cage. As other additives, for example, solid lubricants such as polytetrafluoroethylene resin, inorganic fillers, antioxidants, antistatic agents, mold release agents, etc. can be blended.

[0056] Each material constituting the above resin material can be mixed with a Henschel mixer, ball mixer, ribbon blender, etc. as necessary, and then melt-kneaded with a melt extruder such as a twin-screw kneading extruder to obtain molding pellets. In addition, the filler may be introduced by side feeding when melt-kneading with a twin-screw extruder or the like.

Industrial Applicability

[0057] The cage for a rolling bearing of the present invention can suppress an increase in friction and an increase in torque during bearing operation, even though a resin swelling portion (convex portion) is formed in the welded portion. Therefore, it can be suitably used as a cage for various rolling bearings used in automobiles, motors, machine tools, and the like.

Explanation of reference numerals

[0058] 1 Cage 2 Annular portion 3 Column portion 4 Pocket portion 5 Convex portion 6 Extrusion pin mark 7 Cylindrical roller 11 Double-row cylindrical roller bearing 12 Inner ring 13 Outer ring 14 Cylindrical roller 21 Injection molding machine 22 Hopper 23 Cylinder 24 Heater 25 Screw 26 Cylinder nozzle 27 Mold 28 Extrusion pin W Welded portion

Claims

1. A rolling bearing cage having an annular portion and a plurality of columnar portions extending axially in one direction from the annular portion, for holding rolling elements between the circumferential directions of the columnar portions, the rolling bearing cage is integrally formed by injection molding of the annular portion and the columnar portions, and has a welded portion at least in the annular portion, the welded portion is formed to extend axially from the annular portion to the columnar portion, and a convex portion bulging axially is formed only on the axial end face of the annular portion where the welded portion is formed. A rolling bearing cage characterized by this.

2. When the axial dimension of the convex portion is H and the axial thickness of the annular portion at the location where the convex portion is not formed is T, the rolling bearing cage according to claim 1, characterized in that (H×100 / T)<6.5% is satisfied.

3. The rolling bearing cage according to claim 1 or claim 2, characterized in that a plurality of the convex portions are formed at equal intervals in the circumferential direction.

4. The rolling bearing cage according to any one of claims 1 to 3, characterized in that the number of the convex portions is half the number of the columnar portions.

5. The rolling bearing cage is a comb-type cage, and an extrusion pin mark is formed on the end side opposite to the axial end side where the convex portion is formed. The rolling bearing cage according to any one of claims 1 to 4, characterized by this.

6. The rolling bearing cage according to any one of claims 1 to 5, characterized in that the rolling bearing cage uses polyetheretherketone (PEEK) resin as a base resin and contains a fiber reinforcing agent.

7. A rolling bearing comprising an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling elements, the rolling bearing, characterized in that the cage is the rolling bearing cage according to any one of claims 1 to 6.

8. The rolling bearing is a double-row cylindrical roller bearing, and has a pair of comb-type cages separated by left and right rows as the cage, and the convex portion is formed on the mating surface of these cages. The rolling bearing according to claim 7, characterized by this.

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