KR-102963507-B1 - Resin retainer for ball bearings and ball bearings

Abstract

A resin retainer (20) for a ball bearing is formed by combining a first retainer element (30) and a second retainer element (50) in the axial direction. The first retainer element (30) has a pocket portion (31), a first connecting portion (32), and a fitting portion (41). The second retainer element (50) has a pocket-opposing portion (51), a second connecting portion (52), and a fitting portion (53). The pocket portion (31) is provided with a pair of protrusions (33) that are circumferentially opposite to each other and form a pocket surface (35), and the ball (13) is retained only by the pocket surface (35) of the first retainer element (30). The pocket opposing portion (51) has a partial cylindrical surface (51a) having a radius (r1) greater than the sum of the radius (R) of the ball (13) and the axial displacement amount (Δa) of the first retainer element (30) and the second retainer element (50). Accordingly, the generation of stress that separates the engagement between the first retainer element and the second retainer element that engage with each other is suppressed, the engagement portion can be downsized, and a resin retainer for a ball bearing and a ball bearing with a high degree of freedom in retainer design are provided.

Inventors

• 도리이 게이스케

Assignees

• 닛본 세이고 가부시끼가이샤

Dates

Publication Date

20260511

Application Date

20210903

Priority Date

20200911

Claims (5)

1. A resin retainer for a ball bearing formed by combining a first retainer element made of a synthetic resin formed in a ring shape and a second retainer element made of a synthetic resin formed in a ring shape in the axial direction, The first retaining element has a plurality of pocket surfaces each formed to allow the ball to move freely, a plurality of pocket portions formed at equal intervals in the circumferential direction, and a plurality of first connecting portions connecting adjacent pocket portions to each other. The second retaining element has a plurality of pocket opposing parts axially opposite to each of the plurality of pocket surfaces to cover the openings of the plurality of pocket surfaces, and a plurality of second connecting parts connecting the adjacent pocket opposing parts to each other. Each pocket portion of the first retainer element protrudes toward the second retainer element side with respect to the first connecting portion and faces each other in a circumferential direction, and has a pair of protrusions forming the pocket surface. The first retainer element and the second retainer element are combined by engaging a fitting portion formed on either the first connecting portion or the second connecting portion and a hooked-in portion formed on the other of the first connecting portion or the second connecting portion. The pocket-opposing portion of the second retainer element has an inner surface facing away from the ball, and The above ball is maintained only by the pocket surface of the above first retainer element, and The above-mentioned fitting part is formed in an axial shape by having a cylindrical shaft portion formed protruding from one of the above-mentioned connecting parts and an elastically deformable claw portion formed at the tip, and The above-mentioned interlocking part is formed at the connecting part of the other side and has a cylindrical hole part that is fitted with the cylindrical shaft part with a gap of 0 or less, and an interlocking hole through which the elastically deformed claw part can pass. The claw portion of the elastically returned hook portion is fixed by being hooked onto a hook surface formed in the opening of the hook hole, and Each pocket-opposite portion of the second retainer element covers the outer surface of the pair of protrusions of the first retainer element and has a pair of concave portions that are more concave than the inner surface, A resin retainer for a ball bearing, characterized in that a predetermined gap is formed between the outer surface of the pair of protrusions of the first retainer element and the surface of the pair of concave portions.
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4. In Article 1, A resin retainer for a ball bearing, wherein, in the pocket-opposite portion of the second retainer element, the surface facing away from the ball is a partial cylindrical surface having a radius of curvature greater than the sum of the radius of the ball and the axial displacement of the first retainer element and the second retainer element.
5. A ball bearing having an inner ring having an inner ring raceway on its outer surface, an outer ring having an outer ring raceway on its inner surface, and a plurality of balls maintained between the inner ring raceway and the outer ring raceway so as to be freely driven by a retainer, and which is grease-lubricated, A ball bearing characterized in that the above retainer is a resin retainer for a ball bearing as described in claim 1 or claim 4.

Description

Resin retainer for ball bearings and ball bearings The present invention relates to a resin retainer for ball bearings and ball bearings, and in particular, to a resin retainer for ball bearings and ball bearings applicable to motors or home appliances, etc., where high quietness is required in grease lubrication. It is known that in conventional resin retainers for ball bearings, a pair of elements each having a rim portion and a column portion are combined, and the engaging portion and the engaging portion of each column portion are engaged in a manner that prevents displacement of the two rim portions from separating from each other, thereby improving the strength of the retainer (see Patent Document 1). In addition, for high-speed rotation applications, it is known that a cover body is mounted on the retainer body to prevent the retainer body from being deformed by centrifugal force (see Patent Document 2). Figure 1 is a partial cross-sectional view of a ball bearing. FIG. 2 is a perspective view of a resin retainer for a ball bearing shown in FIG. 1. Figure 3 is a partially enlarged side view showing a disassembled resin retainer for a ball bearing shown in Figure 2. Figure 4 is an explanatory diagram for explaining the height of a pair of protrusions. FIG. 5 is an explanatory diagram for explaining the angle (α) formed by a virtual line (A) passing through the center of the ball and the point of contact of the tip of the protrusion, and a virtual vertical plane (B) passing through the center of the ball, when the ball contacts the tip of the protrusion. Figure 6 is an explanatory diagram showing the state in which the retainer is axially misaligned with respect to the ball, compared to the neutral state. FIG. 7 is an enlarged perspective view showing a portion of the retainer broken off. FIG. 8 is a perspective view showing the case where misalignment has occurred in a conventional retainer. Hereinafter, an embodiment of a resin retainer for a ball bearing and a ball bearing related to the present invention will be described in detail based on the drawings. In addition, the ball bearing of this embodiment is used at a rotational speed of, for example, 3,000 to 30,000 min⁻¹ , and is particularly suitable for use as a machining center or a lathe. As shown in FIG. 1, the ball bearing (10) of the present embodiment is configured by concentrically arranging an outer ring (11) having an outer ring raceway (11a) on its inner circumference and an inner ring (12) having an inner ring raceway (12a) on its outer circumference, and installing a plurality of balls (13) between the outer ring raceway (11a) and the inner ring raceway (12a) so that they can freely move. In addition, the balls (13) are lubricated by grease sealed within the bearing space. Furthermore, the outer ring (11), the inner ring (12), and the balls (13) are each made of steel, for example, alloy steel. A plurality of balls (13) are held so as to be freely driven at a predetermined pitch by a resin retainer (hereinafter also simply called a retainer) (20) for ball bearings. The retainer (20) is formed by injection molding a synthetic resin. In addition, the retainer (20) has a configuration in which a first retainer element (30) and a second retainer element (50) are combined in the axial direction. The detailed structure of the first retainer element (30) and the second retainer element (50) will be described in detail later. On both axial sides of the space between the outer ring (11) and the inner ring (12), an unillustrated sealing member may be formed to seal grease inside the bearing or to prevent debris or foreign matter floating outside from entering the bearing. Examples of sealing members include a contact type that is fixedly mounted on the outer ring (11) and has a lip portion that slides in contact with the inner ring (12), a non-contact type that forms a labyrinth between the inner ring (12) and the sealing member, or a sealing member that is fixedly mounted on the inner ring (12). Additionally, the sealing member may be formed only on one axial side or may not be formed at all. FIG. 2 is a perspective view of a resin retainer for a ball bearing, and FIG. 3 is a partially enlarged side view showing a disassembled resin retainer for a ball bearing. The resin retainer (20) for a ball bearing is formed by combining a first retainer element (30) and a second retainer element (50) in the axial direction. As the resin material for the retainer (20), a single unit of engineering plastic such as polyamide resin (Nylon 6, Nylon 66, Nylon 46), polyacetal resin, polyetheretherketone resin (PEEK), polyphenylene sulfide resin (PPS), or polytetrafluoroethylene (PTFE) is used, or a composite material reinforced by containing about 10 to 40 weight percent of short fibers (reinforcing material) such as glass fiber or carbon fiber is used. The first retaining element (30) has a plurality of pocket surfaces (35) that each allow the ball (13) to be f