JP3608611B2 - Rolling bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rolling bearing, and more particularly, to a rolling bearing characterized by a cage that holds a rolling element inserted between an outer ring and an inner ring.
[0002]
[Prior art]
In conventional rolling bearings, rolling elements such as balls and rollers are interposed on the outer circumferential surface and inner race surface of a race ring composed of an inner ring and an outer ring. In order to hold such rolling elements on the raceway surface, an annular cage for holding the rolling elements is inserted between the rolling rings in the rolling bearing.
In particular, in a spindle bearing for a machine tool that is an example of a rolling bearing, it is required to have good characteristics such as vibration and sound in order to improve machining accuracy. In recent years, high-speed rotation properties (that can be used stably for a long time at a high rotation speed) have been demanded for further improving processing efficiency. In order to satisfy such characteristics, conventionally, a cage made of a synthetic resin that is lightweight and excellent in flexibility is often used. Such a cage is formed by injection molding, and is applied to machine tool bearings that are often operated with a very small amount of grease or lubricating oil used in order to minimize heat generation during operation. . In this way, in the machine tool bearing, the lubricant can be minimized, and the agitation resistance of the softening agent such as grease or lubricating oil and the heat generation associated therewith can be suppressed. As a method of manufacturing such a synthetic resin cage, there is a radial draw method.
[0003]
FIG. 8 shows a part of a cross-sectional view of a mold 60 used in the radial-draw type injection molding method. A part of the molding die 60 is generally configured by a movable die 61, a first slide core 62, and a second slide core 63.
The movable die 61 has a cylindrical shape whose outer peripheral surface forms the inner peripheral surface of the cage. A plurality of slide cores (not shown) are arranged on the outer periphery of the movable mold 61, and when the mold 60 is clamped, they form a pocket portion for holding the outer peripheral surface of the cage and the rolling elements. The first slide core 62 and the second slide core 63, which are a part of the plurality of slide cores, have a convex shape in a sectional view, and arc-shaped base portions 62 a and 63 a juxtaposed with the outer peripheral surface of the movable die 61. The base portion is composed of columnar protrusions 62b and 63b which are erected substantially perpendicularly to the surface of the movable mold 61 side and form a pocket portion of the cage.
When the mold 60 is clamped, the protrusions 62b and 63b of the slide cores 62 and 63 come into contact with predetermined positions on the outer peripheral surface of the movable mold 61, and side surfaces 62c of the slide core bases 62a and 63a that are adjacent to each other. , 63c abut to form a cavity space of the cage. Next, by injecting the synthetic resin material into the cavity space, an annular synthetic resin cage 70 having pocket portions arranged at intervals in the circumferential direction is formed.
[0004]
FIG. 9 shows a side view of the cage 70 molded by the mold 60 described above. A parting line PL formed by abutting the side surfaces 62c and 63c of the slide cores 62 and 63 at the time of injection molding is formed between a plurality of adjacent pocket portions 71 on the outer peripheral surface of the cage 70. Yes. FIG. 10 shows a plan view of the cage 70 in FIG.
[0005]
[Problems to be solved by the invention]
The parting line PL on the outer peripheral surface of the cage 70 formed by the radial-draw-type injection molding method is a "burr" protruding in the radial direction of the cage or a protruding "bull" extending in the axial direction. Have. Such a “burr” is worn by the inner surface of the outer ring of the bearing while it is in operation and the retainer 70 is incorporated into the bearing. The bearing will be disturbed.
Conventionally, before the injection molded cage is incorporated in the bearing, the operation of removing the “burr” such as cutting or barrel processing is performed to improve the rotation of the bearing.
However, the removal work of such “burrs” is complicated, leading to an increase in the cost of rolling bearings due to the removal work of “burrs” of the cage.
[0006]
This invention is made | formed in view of such a condition, and it aims at providing the rolling bearing which can reduce work stroke and does not produce a malfunctioning.
[0007]
[Means for Solving the Problems]
The object of the present invention is to provide a rolling bearing in which a rolling element and a cage that holds the rolling element and is guided by the outer ring are interposed between the outer ring and the inner ring, on the outermost peripheral surface of the cage. A rolling bearing in which a recess along the axial direction is formed and a parting line is formed in the recess can be achieved.
[0008]
Here, the “outermost peripheral surface of the cage” refers to the outer peripheral surface located on the outermost side in the radial direction of the annular cage, and at least than the parting line formed on the outer peripheral surface excluding the outermost peripheral surface. The outer peripheral surface located on the outer side in the radial direction of the cage. Moreover, it is preferable that the recessed part formed on the outermost peripheral surface has such a depth that the parting line formed in the recessed part does not protrude outward of the cage from the outermost peripheral surface. .
According to such a rolling bearing, since the parting line formed on the outer peripheral surface of the cage does not protrude from the outermost peripheral surface of the cage, there is no need to post-process the cage after injection molding. Can be incorporated into. Therefore, the assembly process of the rolling bearing can be simplified, and the yield of the cage parts can be improved. Furthermore, even when the cage is incorporated in the bearing, the parting line formed on the outer circumferential surface of the cage does not slide on the inner circumferential surface of the outer ring of the rolling bearing. That is, no malfunction occurs due to parting line wear, torque fluctuations, etc. during operation of the rolling bearing.
[0009]
Also, in this case, a plurality of fixed molds that form one end of the cage, a cylindrical movable mold that forms the inner peripheral surface and the other end of the cage, and a plurality of the molds are arranged on the outer periphery of the movable mold. And having an arcuate base portion juxtaposed with the outer peripheral surface of the movable mold, and a protrusion erected substantially perpendicularly to the movable mold side surface of the base section, the holding When the mold comprising the outer peripheral surface of the vessel and the slide core that forms the pocket portion is clamped, the projecting tip end surface of the slide core abuts on the outer peripheral surface of the movable mold, and the base portions of the slide core adjacent to each other In the manufacturing apparatus of a rolling bearing cage for forming a cage by forming a cavity space on the outer periphery of the movable mold and injecting a synthetic resin material into the cavity space, When the side surfaces of the adjacent bases contact each other A protrusion projecting toward the movable mold is provided on the inner peripheral surface of the abutting portion of the base, which is the outermost peripheral surface of the cage, and when the synthetic resin material is injected, the outer peripheral surface of the cage is It is preferable that the formed parting line is formed in a recess formed by the protrusion.
[0010]
According to such a rolling bearing cage manufacturing apparatus, the parting line formed on the outer circumferential surface of the cage does not protrude from the outermost circumferential surface of the cage, so that the cage is post-processed after injection molding. There is no need to do. Therefore, the assembly process of the rolling bearing can be simplified, and the yield of the cage parts can be improved.
As the “synthetic resin material”, polyamide 66, polyamide 46, polyphenylene sulfide, thermoplastic polyimide, polyether ether ketone, or the like can be used as a base material. Furthermore, in order to improve the strength of the cage, it is preferable to add about 10 to 40% by weight of glass fiber, and about 10 to 30% by weight of carbon fiber and aramid fiber. Although fiber and aramid fiber are more preferable, glass fiber can also be selected according to use. If the amount of carbon fiber or aramid fiber added is 10% by weight or less, the strength is not sufficiently maintained, and if it is 30% by weight or more, the moldability is deteriorated and the appearance is also deteriorated. More preferably, when the addition amount of carbon fiber or aramid fiber is 20 to 30% by weight, both strength and formability are improved. In the case of glass fiber, 10 to 40% by weight is preferable, for the same reason as above. It is.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments described below, members and the like having the same configurations and functions as those already described are denoted by the same or corresponding reference numerals in the drawings, and description thereof is simplified or omitted.
[0012]
FIG. 1 shows a part of a side view of a cage 10 incorporated in a rolling bearing according to the first embodiment of the present invention. FIG. 2 is a part of a plan view of the cage 10 shown in FIG.
As shown in FIG. 1, the cage 10 has a cylindrical shape made of a resin having a predetermined width, and has a pocket portion 11 that holds a rolling element with an interval in the circumferential direction. On the outer peripheral surface of the cage 10, a recess 12 extending in the axial direction of the cage is formed between the adjacent pocket portions 11, and a parting line PL is formed in the recess 12.
As shown in FIG. 2, the concave portion 12 has a substantially semicircular sectional view that curves from the outer peripheral surface of the cage toward the inside of the cage. A parting line PL is formed at substantially the center in the recess 12.
[0013]
FIG. 3 shows a part of a mold 20 used when the cage 10 shown in FIG. 1 is molded. A part of the molding die 20 is schematically constituted by a movable die 21, a first slide core 22, and a second slide core 23.
The movable mold 21 has a cylindrical shape whose outer peripheral surface forms the inner peripheral surface of the cage. The first slide core 22 and the second slide core 23, which are a part of the plurality of slide cores arranged on the outer periphery of the movable mold 21, have a substantially convex shape in a sectional view, and are juxtaposed with the outer peripheral surface of the movable mold 21. And arcuate bases 22a and 23a that form the inner peripheral surface of the cage, and columnar protrusions 22b that stand substantially perpendicular to the surface of the base on the side of the movable mold 21 and that form a pocket portion of the cage. , 23b. Projections 22d and 23d are formed at the ends of the inner surfaces of the base portions 22a and 23a of the slide cores 22 and 23 on the movable mold 21 side.
When the mold 20 is clamped and the side surfaces 22c and 23c of the base portions 22a and 23a of the slide cores adjacent to each other come into contact with each other, the protrusions 22d and 23d come into contact with each other to form the protrusion 12a.
Next, by injecting a resin material into the cavity space, an annular synthetic resin cage 10 having pocket portions arranged at intervals in the circumferential direction is formed.
[0014]
According to such a configuration of the present embodiment, the parting line PL formed on the outer circumferential surface of the cage 10 does not protrude from the outer circumferential surface of the cage 10 as shown in FIG. There is no need for post-processing such as removal of “burrs” after injection molding. Therefore, the assembly process of the rolling bearing can be simplified, and the yield of parts of the cage 10 can be improved. Furthermore, even when the cage 10 is incorporated in the bearing, the parting line PL formed on the outer circumferential surface of the cage 10 does not slide into contact with the inner circumferential surface of the outer ring of the rolling bearing. That is, no malfunction occurs due to wear, torque fluctuation, or the like during operation of the rolling bearing. In the present embodiment, the protruding shape is provided on all of the plurality of slide cores arranged on the outer periphery of the movable mold 21.
[0015]
FIG. 4 shows a part of a plan view of a rolling bearing cage 30 according to the second embodiment of the present invention.
In the cage 30 shown in FIG. 4, the shape of the concave portion 32 formed on the outer peripheral surface of the cage 30 is substantially triangular when viewed in cross section. That is, the concave portion 32 has a triangular shape that protrudes from the outer peripheral side to the inner peripheral side of the cage, so that the shape of the slide core of the mold that forms the concave portion 32 becomes a simple shape. Processing of the mold becomes easy. Other configurations and operations are the same as those in the first embodiment described above.
[0016]
FIG. 5 shows a part of a plan view of a rolling bearing cage 40 according to a third embodiment of the present invention.
In the cage 40 shown in FIG. 5, the shape of the recess 42 formed on the outer peripheral surface of the cage 40 has a substantially rectangular shape in sectional view. By doing so, the bottom surface of the substantially rectangular recess 42 is formed wide, which is effective when the parting line PL is formed wide. Other configurations and operations are the same as those in the first embodiment described above.
[0017]
FIG. 6 shows a side view of a rolling bearing cage 50 according to a fourth embodiment of the present invention. FIG. 7 shows a plan view of the cage 50 as viewed from the direction A.
In the cage 50 shown in FIG. 6, the outer peripheral surface in the vicinity of one end in the axial direction of the cage 50 protrudes outward in the radial direction of the cage 50 from the other outer peripheral surface to form a stepped portion 53. Yes. Further, among the parting lines PL formed on the outer peripheral surface along the axial direction of the cage 50, the parting line PL formed on the stepped portion 53 is formed in the concave portion 52 having a semicircular cross-sectional view. Yes.
[0018]
In such a configuration of the present embodiment, the stepped portion 53 that forms the outermost peripheral surface of the cage 50 is provided, so that the cage 50 can move the stepped portion 53 and the inner circumference of the outer ring during the operation of the rolling bearing. The surface is in sliding contact. That is, by forming the recess 52 for housing the parting line PL in the stepped portion 53 of the cage 50, the parting line PL formed on the outer circumferential surface of the cage 50 protrudes from the outermost circumferential surface of the cage 50. There is nothing. That is, even if the cage 50 is incorporated into a rolling bearing without post-processing such as removal of the outer surface “burr”, the stepped portion 53 of the cage 50 is in sliding contact with the inner circumferential surface of the outer ring of the rolling bearing, etc. No malfunction occurs due to wear, torque fluctuation, etc. during operation of the rolling bearing.
Moreover, in this embodiment, although the step part 53 was formed in the vicinity of one edge part of the axial direction of the holder | retainer 50, you may form in both edge part vicinity.
[0019]
In addition, this invention is not limited to embodiment mentioned above, A suitable deformation | transformation, improvement, etc. are possible.
In the present invention, the ball bearing is exemplified as the cage of the rolling bearing, but a roller bearing may be adopted.
In the present invention, the shape of the recess is not particularly limited, and may be a pentagon, hexagon, or the like as long as the parting line can be accommodated.
[0020]
【The invention's effect】
As described above, according to the rolling bearing of the present invention, it is not necessary to remove the “burr” of the parting line. ”Does not contact the inner peripheral surface of the outer ring of the rolling bearing, so that malfunctions due to wear, torque fluctuations, etc. do not occur during operation of the rolling bearing.
[Brief description of the drawings]
FIG. 1 is a part of a side view of a rolling bearing cage 10 according to a first embodiment of the present invention.
FIG. 2 is a part of a plan view of the cage 10 shown in FIG.
FIG. 3 is a partial cross-sectional view showing a part of a mold 20 for molding the cage 10 shown in FIG. 1;
FIG. 4 is a part of a plan view of a rolling bearing retainer 30 according to a second embodiment of the present invention.
FIG. 5 is a part of a plan view of a rolling bearing cage 40 according to a third embodiment of the present invention.
FIG. 6 is a part of a side view of a rolling bearing cage 50 according to a fourth embodiment of the present invention.
7 is a part of a plan view of the cage 50 shown in FIG. 6. FIG.
FIG. 8 is a cross-sectional view showing a conventional radial draw mold 60.
FIG. 9 is a part of a side view showing a conventional bearing retainer 70;
10 is a part of a plan view of the retainer 70 shown in FIG. 9. FIG.
[Explanation of symbols]
10, 30, 40, 50, 70 Cage 11, 51, 71 Pocket portion 12, 32, 42, 53 Recess 20, 60 Mold 21, 61 Movable 22, 22, First slide core 22a, 23a, 62a, 63a Base 22b, 23b, 62b, 63b Protrusion 22c, 23c, 62c, 63c Side 23, 63 Second slide core PL Parting line

Claims (1)

In the rolling bearing between the outer ring and the inner ring, a rolling element, and a cage that holds the rolling element and is guided by the outer ring,
A rolling bearing, wherein a concave portion along an axial direction is formed on an outermost peripheral surface of the cage, and a parting line is formed in the concave portion.

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