JP2007247856A - Resin cage for rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin retainer for a rolling bearing with an undercut part which can be molded by a pair of dies. <P>SOLUTION: The resin cage 11 for the rolling bearing is a cylindrical member made of resin with the undercut part which is not projected when viewed from a shaft direction and a parting line extending at a position on its periphery in the axial direction. Its cylindrical shape is formed by welding cut end surfaces 17a, 17b formed at one side and the other side of the peripheral direction of the parting line. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin cage as a component of a rolling bearing.

  As a cage used in a conventional rolling bearing, a machined cage produced by cutting a metal, a press cage produced by pressing a steel plate, or a resin material manufactured by injection molding. There are resin cages.

  Recent rolling bearing cages have complicated shapes, and resin cages by injection molding with a high degree of freedom in shape have been attracting attention. In addition, since the injection molding has a very high production efficiency, it has an advantage that the manufacturing cost can be suppressed in the case of producing a large lot.

  Referring to FIG. 16, for example, a cage 101 manufactured by injection molding of a resin material includes a pair of ring portions 102 and 103 and a plurality of column portions 104 arranged between the pair of ring portions 102 and 103. And a pocket 105 for accommodating the rolling elements 106 between the adjacent pillars 104. The cage 101 has portions 102a and 103a (hereinafter referred to as “undercut portions”) that are not projected when viewed from the axial direction (the directions of arrows A and B in the figure).

Such a cage 101 is generally formed by combining two members due to the problem of releasability during injection molding. For example, a cage formed by combining two members in this way is described in Japanese Patent Application Laid-Open No. 11-264419 (Patent Document 1). Referring to FIG. 17, the rolling bearing retainer 111 described in the publication includes a pair of ring portions 112, 113 and a plurality of column portions 114 disposed between the pair of ring portions 112, 113. A plurality of pockets 115 for accommodating rolling elements (not shown) are formed between the adjacent pillar portions 114.
JP-A-11-264419

  The rolling bearing retainer 111 described in the above publication includes a first member 116 including a ring portion 112 on one side and a plurality of column portions 114 protruding in an axial direction from an end surface of the ring portion 112, and a ring on the other side. The second member 117 including the portion 113 is combined.

  Thus, in order to manufacture the rolling bearing retainer 111 configured by combining the first and second members 116 and 117 having different shapes, it is necessary to prepare two sets of molds having different shapes. There is a problem of high costs.

  Further, in the cage 101 having the undercut portions 102a and 103a as shown in FIG. 16, there is a problem that the bearing life is remarkably reduced due to insufficient lubrication depending on the intended use.

  Accordingly, an object of the present invention is to provide a rolling bearing retainer having an undercut portion, which has a shape that can be molded by a set of molds and is excellent in lubricity. That is.

  A resin cage for a rolling bearing according to the present invention is a substantially cylindrical member made of resin having an undercut portion that is not projected when viewed from the axial direction and a dividing line that extends in the axial direction at one location on the circumference. The cut end surfaces formed on one side and the other side in the circumferential direction of the dividing line were welded to form a cylindrical shape.

  The resin cage for a rolling bearing having the above-described structure can be taken out by molding as a single unit using a set of molds and expanding the divided portion using the elasticity of the resin material. (Hereafter, this method is called "unreasonable"). As a result, it is possible to reduce the initial cost for manufacturing the mold. Further, when incorporated in the bearing, the cylindrical retainer is formed by welding the cut end faces on one side and the other side, so that the rotation of the bearing is stabilized.

  In addition, as a method of connecting the cut end faces, a method of mechanically connecting with a rivet or the like, or a method of connecting via an adhesive or the like can be considered. In these methods, the rivet hole may be damaged due to stress concentration, or the cage material may be deteriorated by the adhesive component. Therefore, these problems can be prevented by using a welding technique for melting and joining the cut end faces.

  Preferably, the substantially cylindrical member includes a pair of ring portions and a plurality of column portions arranged between the pair of ring portions, and the dividing line is formed in the column portions. More preferably, the cut end surface includes a plurality of wall surfaces located on different surfaces.

  By setting it as the said structure, the area of a welding surface increases and it can maintain sufficient joining strength. As a result, it is possible to ensure sufficient strength against a radial load or an axial load applied to the cage when the bearing rotates.

  Preferably, the cylindrical substantially cylindrical member is heat-fixed to increase the roundness. A cage formed of a resin material has a variation in roundness in a state immediately after manufacture. In particular, the resin-made cage for a rolling bearing having the above-described configuration may cause the roundness to be low because the mold is forcibly removed. Therefore, it is effective to increase the roundness of the cage by performing heat setting after welding the cut end faces.

  As one embodiment, the resin-made cage for a rolling bearing is formed of a material containing engineering plastic. By using such a material, a lightweight and high-strength resin cage for a rolling bearing can be obtained. Further, since engineering plastic is a thermoplastic resin, ultrasonic welding can be used for welding the cut end faces.

  Preferably, a pocket for accommodating the rolling elements is formed between the adjacent column portions, and an oil groove for supplying lubricating oil to the pocket is provided on the axial end surfaces of the pair of ring portions. Thereby, since the supply amount of the lubricating oil to the inside of the pocket increases, it is possible to obtain a roller bearing resin cage excellent in lubricity.

  According to the present invention, even a rolling bearing retainer having an undercut portion can be molded by a set of molds, so that a resin bearing retainer for a rolling bearing with reduced initial cost can be obtained. . Further, by increasing the amount of lubricating oil supplied to the pockets, it is possible to obtain a resin bearing cage for rolling bearings with excellent lubricity.

  With reference to FIGS. 1-9, the resin-made cage | basket 11 for rolling bearings concerning one Embodiment of this invention is demonstrated. 1 is a view showing a state in which a resin bearing 11 for a rolling bearing is divided at one place on the circumference, FIG. 2 is a view showing a state in which a cut end face is welded, and FIG. 3 is for a rolling bearing. FIG. 4 is an enlarged view of the cut end surface, FIGS. 5 to 7 are views in which an oil groove is provided in the undercut portion, and FIGS. 8 and 9 are on the end surface on the axially outer side of the ring portion. It is the figure which provided the oil groove.

  First, referring to FIG. 1, a rolling bearing resin cage 11 includes a pair of ring portions 12, 13 and a plurality of column portions 14 disposed between the pair of ring portions 12, 13. A plurality of pockets 15 for accommodating rolling elements (not shown) are formed between adjacent column portions 14 which are cylindrical members. This rolling bearing resin cage 11 is divided at one place on the circumference at the stage of injection molding. In this embodiment, the column part 14 is divided. As a result, the rolling bearing resin cage 11 is generally C-shaped as a whole, and cut end surfaces 17a and 17b having shapes corresponding to each other are formed on one side and the other side in the circumferential direction.

  Referring to FIG. 2, a rolling bearing resin cage 11 injection-molded in the state shown in FIG. 1 welds the cut end faces on one side and the other side to form a cylindrical shape. At this time, dividing lines 16a extending in the axial direction are formed on the outer diameter surface and the inner diameter surface of the resin cage 11 for the rolling bearing. In the embodiment shown in FIG. 2, the dividing line 16 a is formed on the pillar portion 14. Thereby, since the surface area of the junction part in the case of welding can be enlarged, joining strength can be raised.

  On the other hand, on both end faces in the axial direction, a first radial dividing line having one end in contact with the outer diameter surface of the rolling bearing resin cage 11 and extending inward in the radial direction, and one end in contact with the inner diameter surface and radially outward A dividing line including a second dividing line extending in the direction of the first and second radial dividing lines and a circumferential dividing line extending in a direction intersecting with the other ends of the first and second radial dividing lines. 16b is formed. In the embodiment shown in FIG. 2, the first radial dividing line is set shorter than the second radial dividing line so that the circumferential dividing line passes through the radial center of the column part 14. ing.

  Referring to FIG. 3, when the dividing line 16 is as shown in FIG. 2, the cut end surfaces 17 a and 17 b are configured by combining a plurality of wall surfaces located on different surfaces. Specifically, the cut end faces 17a, 17b are a first radial end face extending radially inward from the outer diameter face of the rolling bearing resin cage 11, and a second radial end face extending radially outward from the inner diameter face. And a circumferential end surface that is in contact with the first and second radial end surfaces and extends in a direction intersecting the first and second radial end surfaces. Thereby, step-like cut end faces 17a and 17b are formed.

  By setting it as the said structure, since the surface area of the joint surface in the case of welding becomes still larger, joining strength further increases. As a result, sufficient strength can be ensured against a radial load and an axial load applied to the resin bearing 11 for the rolling bearing.

  Note that “a plurality of wall surfaces located on different surfaces” does not require that all wall surfaces be located on different surfaces, and a plurality of wall surfaces located on the same surface and surfaces different from these wall surfaces. It may be a combination with a wall surface located above.

  With reference to FIG. 4, the resin cage 11 for a rolling bearing is a cage and roller type needle roller bearing in which needle rollers 18 as rolling elements are accommodated in the respective pockets 15. The pair of ring portions 12 and 13 respectively have undercut portions 12a and 13a that are not projected when viewed in the axial direction (the directions of arrows A and B in the figure).

  Further, referring to FIG. 5, the first central portion disposed on the outer diameter side of the wall surface facing the pocket 15 of the pillar portion 14 on the outer diameter side to prevent the needle rollers 18 from coming out radially outward. Lubricating oil between the roller stopper 14a, the second roller stopper 14b disposed on the inner diameter side to prevent the needle roller 18 from coming out radially inward, and the first and second roller stoppers 14a, 14b. And an oil sump 14c for storing the oil.

  Further, referring to FIGS. 6 and 7, the undercut portion 13 a is provided with an oil groove 13 b having a circular arc shape extending from the radially inner side of the rolling bearing resin retainer 11 to the pocket 15. In addition, although illustration is abbreviate | omitted, you may provide an oil groove also in the undercut part 12a. Further, the cross-sectional shape of the oil groove 13b is not limited to the arc shape, and may be an arbitrary shape. For example, a rectangular shape or the like may be used.

  Referring to FIGS. 8 and 9, the axially outer end face of the ring portion 12 has a circumferential oil groove extending in the circumferential direction, and from the radially outer side to the radially inner side so as to intersect the circumferential oil groove. A plurality of extending radial oil grooves are formed (shaded portions in FIG. 8 indicate circumferential oil grooves and radial oil grooves). In addition, the pocket 15 is arrange | positioned on the radial direction oil groove on the extended line pulled along the outer diameter surface and inner diameter surface of the ring part 12 from the radial direction outer side and the radial direction inner side edge part. Although not shown, the ring portion 13 may have the same configuration.

  As described above, by providing an oil groove for supplying lubricating oil to the pocket 15 on the axially outer and inner end faces of the ring portions 12 and 13, a resin bearing for a rolling bearing having excellent lubricity. Can be obtained.

  Next, with reference to FIG. 10 and FIG. 11, other embodiment of the oil groove provided in the end surface of the axial direction outer side of a ring part is described. The basic configuration is the same as that of the rolling bearing resin cage 11 shown in FIGS.

  A circumferential oil groove extending in the circumferential direction on the end surface of the ring portion 22 of the resin cage 21 for the rolling bearing and extending radially inward from the radially outer side so as to intersect the circumferential oil groove. A plurality of radial oil grooves are formed (shaded portions in FIG. 10 indicate circumferential oil grooves and radial oil grooves). The radially outer and inner ends of each radial oil groove are provided at positions corresponding to the circumferential pockets 25. Although not shown, the other ring portion may have the same configuration.

  Furthermore, with reference to FIG. 12 and FIG. 13, other embodiment of the oil groove provided in the end surface of the axial direction outer side of a ring part is described. The basic configuration is the same as that of the rolling bearing resin cage 11 shown in FIGS.

  A substantially circular shape in which a part of the circumference intersects with the outer diameter surface or the inner diameter surface at a position corresponding to the circumferential pocket 35 on the end surface in the axial direction of the ring portion 32 of the resin cage 31 for the rolling bearing. Are formed (the shaded area in FIG. 12 indicates the recess). In addition, this recessed part functions as an oil groove similarly to embodiment shown in FIGS. Although not shown, the other ring portion may have the same configuration.

  Next, the manufacturing method of the resin cage 11 for a rolling bearing according to the above embodiment will be described.

  First, as a starting material, engineering plastics such as POM (polyacetal), PA (polyamide), PPS (polyphenylene sulfite), PEEK (polyether ether ketone), PI (polyimide) are employed as the base resin.

  As a first step, the starting material is injection molded, and a substantially C-shaped resin bearing 11 for a rolling bearing as shown in FIG. 1 is integrally molded. For injection molding, an outer mold (not shown) for determining the outer diameter shape, an inner mold (not shown) for determining the inner diameter shape, and a pocket mold (not shown) for determining the shape of the pocket 15 are used. A set of molds is used.

  Since the inner mold cannot be pulled out as it is caught by the undercut portions 12a and 13a, the rolling bearing resin retainer 11 is elastically deformed so as to widen the cut end surfaces 17a and 17b and forcibly removed. Thus, since the resin-made cage 11 for a rolling bearing according to one embodiment of the present invention can be injection-molded with a set of molds, the initial cost can be suppressed. The oil grooves provided on the inner and outer end faces in the axial direction of the ring portions 12 and 13 may be formed at the time of injection molding, or may be formed by cutting or the like after the injection molding.

  As a second step, the cut end faces 17a and 17b are welded to obtain a cylindrical rolling bearing resin cage 11 as shown in FIG. Since the rolling bearing resin cage 11 according to the embodiment of the present invention uses a thermoplastic resin as a starting material, the cut end faces 17a and 17b are welded by, for example, ultrasonic welding.

  The principle of ultrasonic welding is to apply fine ultrasonic vibration while applying pressure in a state where the cut end faces 17a and 17b are abutted. Thereby, frictional heat is generated on the abutting surfaces, and the cut end surfaces 17a and 17b are instantaneously melted and joined.

  Here, as a method of joining the cut end faces 17a and 17b, a method of mechanically joining with a rivet or the like, or a method of joining via an adhesive or the like can be considered. In these methods, the rivet hole may be damaged due to stress concentration, or the cage material may be deteriorated by the adhesive component. Therefore, these problems can be prevented by using a welding technique for melting and joining the cut end faces 17a and 17b.

  In the above embodiment, an example in which the cut end faces 17a and 17b are ultrasonically welded has been described. However, the present invention is not limited to this, and any method can be used. For example, vibration welding, orbital welding, infrared laser welding, or the like can be used.

  As a third step, heat fixation is performed to increase the roundness of the cylindrical roller bearing resin retainer 11. The term “heat setting” in the present specification refers to a method of obtaining a predetermined shape by utilizing the property of a resin material that does not shrink unless heated to a temperature higher than that temperature. Shall.

  As a thermal jig used for heat fixation, for example, referring to FIGS. 14 and 15, a male jig 19 having a shaft portion 19a and a female jig 20 having a cylindrical portion 20a are used. The cross-sectional shape of the outer diameter surface of the shaft portion 19a of the male jig 19 and the inner diameter surface of the cylindrical portion 20a of the female jig 20 is a perfect circle.

  Further, the outer diameter dimension of the shaft portion 19a of the male jig 19 matches the design value of the inner diameter dimension of the rolling bearing resin cage 11, and the inner diameter dimension of the female jig 20 is equal to that of the rolling bearing resin cage 11. It matches the design value of the outer diameter. On the other hand, the inner diameter of the roller bearing resin cage 11 at the time of injection molding is set slightly smaller than the design value.

  As a specific heat fixing process, first, the cylindrical roller bearing resin cage 11 is fitted into the shaft portion 19 a of the male jig 19. At this time, since the outer diameter surface of the shaft portion 19a is slightly larger than the inner diameter of the rolling bearing resin cage 11, a tensile load is applied to the rolling bearing resin cage 11. Next, the female jig 20 is inserted into the shaft portion 19a so as to cover the rolling bearing resin cage 11 fitted into the shaft portion 19a.

  It should be noted that one rolling bearing resin cage 11 may be fitted into the male jig 19 for heat fixing, but from the viewpoint of efficiency, as shown in FIG. 14, a plurality of rolling bearing resin cages are used. It is desirable to fit 11 into the male jig 19 and heat fix at the same time.

  In this state, the heat setting jigs 19 and 20 are heated to a predetermined temperature for a predetermined time. Accordingly, the resin cage 11 for the rolling bearing becomes a perfect circle along the outer diameter surface of the male jig 19 and the inner diameter surface of the female jig 20. The heating temperature is set higher than the maximum temperature reached when the rolling bearing resin cage 11 is used as a bearing. Thereby, the roundness of the rolling bearing resin cage 11 does not deteriorate during the rotation of the bearing. Further, unlike the method of forcibly deforming by applying pressure such as a press, heat fixation does not cause residual stress in the rolling bearing resin cage 11 and therefore does not return to its original shape during rotation of the bearing. .

  In addition, this invention is not restricted to the resin cage 11 for rolling bearings which concerns on said embodiment, It can apply to the resin cages of arbitrary shapes.

  Further, in each of the above embodiments, the example in which the dividing line is formed on the column portion has been described, but the present invention is not limited to this, and the dividing line can be provided in an arbitrary place. Furthermore, the shape of the cut end face can also be an arbitrary shape.

  In each of the above embodiments, an example of a cage-and-roller type provided with the resin cage 11 for rolling bearings and the needle roller 18 is shown, but the inner ring and / or the outer ring is not limited to this. Needle roller bearings may be used.

  Furthermore, the resin cage for a rolling bearing according to the present invention is not limited to a needle roller bearing, but a cylindrical roller bearing, a tapered roller bearing, a self-aligning roller bearing, a deep groove ball bearing, an angular ball bearing, and a four-point contact ball bearing. Regardless of whether the rolling element is a roller or a ball, it can be applied to any rolling bearing regardless of whether it is a single row or a double row.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used for a resin cage employed in a rolling bearing.

It is a figure which shows the resin-made cage for rolling bearings concerning one Embodiment of this invention, Comprising: It is a figure which shows the state immediately after injection molding. It is a figure which shows the resin-made cage for rolling bearings concerning one Embodiment of this invention, Comprising: It is a figure which shows the state which welded the cut end surface and formed the cylindrical shape. It is an enlarged view of the cut end surface of FIG. It is sectional drawing of the resin cage for rolling bearings concerning one Embodiment of this invention. FIG. 5 is a view taken in the direction of the arrow V in FIG. 4 and shows an oil groove on an end surface on the axially inner side of the ring portion. FIG. 6 is a view taken in the direction of an arrow VI in FIG. 5 and showing a cross-sectional shape of the oil groove. It is a front view of the resin-made cage for rolling bearings concerning one embodiment of this invention. It is a figure which shows an example of the oil groove of the end surface of the axial direction outer side of a ring part. It is the elements on larger scale of FIG. It is a figure which shows the other example of the oil groove of the end surface of the axial direction outer side of a ring part. It is the elements on larger scale of FIG. It is a figure which shows the other example of the oil groove of the end surface of the axial direction outer side of a ring part. It is the elements on larger scale of FIG. It is a figure which shows the method of heat-fixing the resin cage for rolling bearings, Comprising: It is a figure which shows the state before connecting a male jig and a female jig. It is a figure which shows the method of heat-fixing the resin cage for rolling bearings, Comprising: It is a figure which shows the state after connecting the male jig and the female jig. It is a figure which shows an example of the conventional resin-made cages for rolling bearings. It is a figure which shows the other example of the conventional resin-made cages for rolling bearings.

Explanation of symbols

  11, 21, 31, 101, 111 Resin cage for rolling bearing, 12, 13, 22, 32, 102, 103, 112, 113 ring part, 12a, 13a, 22a, 23a, 102a, 103a undercut part, 14, 24, 104, 114 Pillar part, 14a, 14b Rolling stopper part, 14c Oil sump, 15, 25, 35, 105, 115 Pocket, 16, 16a, 16b Dividing line, 17, 17a, 17b Cut end face, 18, 28, 38 Needle roller, 19, 20 Heat fixing jig, 19a Shaft portion, 20a Cylindrical portion, 106 First member, 107 Second member.

Claims (6)

An undercut portion that is not projected when viewed from the axial direction;
A substantially cylindrical member made of resin having a dividing line extending in the axial direction at one place on the circumference,
A resin cage for a rolling bearing, in which cut end surfaces formed on one side and the other side in the circumferential direction of the dividing line are welded to form a cylindrical shape. The substantially cylindrical member includes a pair of ring portions and a plurality of column portions disposed between the rings,
The said parting line is a resin-made cage for rolling bearings of Claim 1 formed in the said pillar part.   The resin-made cage for a rolling bearing according to claim 1, wherein the cut end surface includes a plurality of wall surfaces located on different surfaces.   The roller-shaped resin cage for a rolling bearing according to any one of claims 1 to 3, wherein the cylindrical ring portion is heat-fixed to increase roundness after welding of the cut end faces.   The resin cage for a rolling bearing according to any one of claims 1 to 4, wherein the resin cage for the rolling bearing is formed of a material containing engineering plastic. Between the adjacent column parts, a pocket for accommodating a rolling element is formed,
The rolling cage resin cage according to any one of claims 2 to 5, wherein an oil groove for supplying lubricating oil to the pocket is provided on an axial end surface of the pair of ring portions.

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