JP2020046069A - Resin-made cage and rolling bearing - Google Patents

Abstract

To provide a resin-made cage which is high in the rigidity of a weld portion at injection molding, also high in fracture prevention performance, and possesses a tension breakage elongation force, and to provide a rolling bearing having durability for withstanding vibration and a large bending moment load.SOLUTION: A resin-made crown-type cage 1 is provided in which a weld line appearing on inner and outer peripheral surfaces of the cage 1 has an inclination angles of 17° or larger with respect to an X axis, or a weld portion s A', B' or C' have predetermined cross- sectional areas satisfying relationships represented by the following formulae (1) and (2). (1) W/(π(Da/2))≥0.15( in the formula, W represents a cross sectional area of a weld portion (mm), Da represents a diameter (mm) of a ball accommodated in a pocket, and (π(Da/2)) is a cross-sectional area (mm) of the ball in a diameter direction. (2) 3<(L/E)/100<19(in the formula, E represents the elongation (mm) of the crown-shaped cage in a breakage direction caused by a tension breakage load, and L is a breakage load (N)/weld part cross sectional-area (mm).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin cage for a rolling bearing, a method for manufacturing the same, and a rolling bearing provided with the resin cage.

  Generally, a cage incorporated in a rolling bearing is a component that holds a ball during rotation. Metal cages such as iron plates are generally made by press molding, and have high material strength and tensile strength.

  On the other hand, resin cages are inferior in strength to metal cages, but can be mass-produced by injection molding, which is advantageous in cost, and are excellent in flexibility, wear resistance, corrosion resistance, etc. Problems due to powder hardly occur, and further weight reduction can be achieved. For this reason, resin cages can greatly contribute to the improvement of bearing performance, and are widely used in many technical fields such as automobiles, electricity, and industrial machines.

  For example, a composition in which a polyphenylene sulfide-based resin is blended with an elastomer component and 20 to 50% by weight of a glass fiber reinforcement, the Izod impact strength is adjusted to 130 J / m (notched) or more, Further, a synthetic resin cage having a tensile elongation at break adjusted to 2% or more is known (Patent Document 1).

  When such a synthetic resin cage is manufactured by injection molding, a portion called a weld or a weld line is formed at a position facing the gate of the molten resin molding material.

  By the way, when the molten resin molding material flows in the cavity by being divided into two parts, the weld is considered to occur because the surface of the resin is slightly solidified and joined at a place where the flows join again and join. . Such a weld is also observable from the appearance of the injection-molded product, and is also a portion having low strength.

  As a synthetic resin crown-shaped cage manufactured by injection molding, by placing an injection molding gate in the concave part of the cage surface facing the pocket, the weld is thick and the column part where load does not act easily (Patent Document 2).

  In addition, as for the cage for tapered roller bearings, as a means for increasing the strength of the weld portion, the cage is formed so that the weld is formed at the center between the pillars connecting the annular portions with the least possible load. It is known to dispose a gate in an annular part on the extension of the pillar part (Patent Document 3).

  In addition, in order to improve the point that the molten resin and the added reinforcing fiber are not mixed uniformly in the weld portion, a resin reservoir is provided in the mold to guide the molten resin, and the resin and the added reinforcing fiber are removed from the weld. There is known a method in which the strength is reduced at a weld portion by mixing at a predetermined portion of a cavity to be formed and dispersing randomly without orientation (Patent Document 4).

JP 2005-114098 A JP-A-2006-180430 JP 2006-070926 A JP 2014-231911 A

However, in the cage described in Patent Literature 2 described above, in order to generate a weld in a pillar portion and obtain good moldability, injection molding is performed from a plurality of gates to form a gate near the center of a pocket. It is necessary to install the gate, but in a cage having a small thickness at the center of the pocket, such as a crown-shaped cage for a small ball bearing, the gate may not be installed at a predetermined position or a plurality of gates.
Further, in a small cage, it is difficult to install a gate of a required size for supplying a sufficient amount of the molten resin so that the strength is not reduced due to insufficient supply of the molten resin.

  By the way, in the method for manufacturing a synthetic resin cage described in Patent Document 3 described above, a weld is formed at a central portion between columns connecting both of the large-diameter and small-diameter annular portions of the tapered roller bearing retainer. Is formed. In this case, the strength of the corner portion that is easily broken can be ensured, but the strength of the central portion between the columns that withstands tension is small according to the relatively small cross-sectional area of the weld.

  In addition, the crown type cage having an even number of pockets is less likely to be restricted by the gate position by setting the gate position in the center between the pockets, and forming the weld in the center between the pockets to reduce the cross-sectional area of the weld. Can be larger.

  However, in the crown type cage having an odd number of pockets, if the gate position is set at the center between the pockets, the weld will be formed on the bottom surface portion on the concave circular curved surface of the pocket, and its sectional area is small. This makes it difficult to adjust the gate position optimally.

  Further, as described in Patent Document 4, in order to guide the molten resin by providing a resin reservoir in a mold, the structure of a mold becomes complicated, and a step of cutting off the resin reservoir after molding is also required. This increases the number of manufacturing steps.

When a rolling bearing is used as a rolling bearing for supporting a crankshaft in an engine device, it is necessary to withstand severe lubrication conditions, high temperature conditions, severe vibrations and loads that tilt the rotating shaft. There is a need for a resin cage made of an injection-molded body having high strength and a stable quality in response to the above.
However, the strength of the injection-molded resin cage cannot be sufficiently enhanced only by the characteristics of the resin used.

  Further, in the metal cage, it is necessary to fix two corrugated iron plate parts for holding the balls with studs. In order to increase the strength of the retainer, the plate thickness of the corrugated parts is increased. Or by applying a special heat treatment or the like. However, it is not easy to easily increase the strength of the metal cage by any of the measures.

  Judging from the properties of the resin material, such a metal cage has a strength evaluated by a breaking load greater than that of the resin cage, but has a smaller elongation at break than the resin cage.

  Therefore, an object of the present invention is to solve the above-mentioned problems, and to make the resin cage of the rolling bearing less likely to break at a weld portion caused by melt molding such as injection molding and to withstand vibration and a large bending moment load. Rolling bearings incorporating resin cages can withstand vibrations and large bending moment loads well, and furthermore, resin bearings with such excellent mechanical properties and durability It is to manufacture a cage efficiently.

  In order to solve the above problems, the inventor of the present application has stated that a resin cage is inferior to a metal cage in terms of strength, but if a certain elongation is added in addition to the strength, a resin cage is better than a metal cage. We thought that it would be difficult to break and could be a durable resin cage.

  Therefore, in the present invention, a plurality of pockets for rotatably accommodating the rolling elements of the rolling bearing are arranged at equal intervals in a circumferential direction of an annular retainer made of a resin molded body, and extend inward from a wall surface of the pocket. The weld line, which appears on the surface of the cage adjacent to the wall surface of the weld portion, is a weld line inclined at an angle of 17 ° or more with respect to the axis of the cage.

  In the resin cage for a rolling bearing of the present invention configured as described above, the weld line that appears on the predetermined surface of the cage is inclined at an angle of 17 ° or more with respect to the axis of the annular cage. As a result, the area occupied by the weld portion in the cross section of the cage (hereinafter, referred to as the cross-sectional area of the weld portion) increases, and the cross section of the weld portion due to the axial load applied to the cage due to the inclination angle (hereinafter, the weld surface). ) Can be reduced. Therefore, the stress generated in the weld portion can be reduced, and the strength of the weld portion can be increased.

  As is clear from Examples and Comparative Examples described later, when the inclination angle of the weld line with respect to the axis of the cage is less than 17 °, the results of the breaking load and the breaking elongation in the strength test of the cage are remarkably reduced and excellent. Mechanical properties and durability cannot be obtained.

  Further, instead of the configuration of the above-described invention, the weld portion is formed so as to straddle a wall surface of the pocket and a surface of a retainer facing the wall surface, and a weld portion represented by the following formula (1). Since the cross-sectional area ratio of the ball or roller and the ratio of the fracture load of the cage to the cross-sectional area of the weld and the breaking elongation indicated by the formula (2), the resin crown-type cage is a weld having a predetermined cross-sectional area that satisfies the ratio. is there.

(1) W / (π (Da / 2) ² ) ≧ 0.15
(Where W is the weld area cross-sectional area (mm ² ), Da represents the diameter (mm) of the ball housed in the pocket, and (π (Da / 2) ² ) is the cross-sectional area of the ball in the diameter direction ( mm ² ).)

(2) 3 <(L / E ³ ) / 100 <19
(Where E represents the elongation (mm) in the breaking direction of the crown-shaped cage (the site at the 3 o'clock and 9 o'clock positions of the crown-shaped cage in FIG. 15A) due to the tensile breaking load, and L Is the breaking load (N) / weld portion cross-sectional area (mm ² ).)

The resin crown type retainer of the present invention configured as described above has a welded portion having a predetermined cross-sectional area that satisfies the mathematical formulas (1) and (2), a concave curved bottom surface of the pocket and the retainer body. In addition to the characteristics of the resin forming the cage, the cross-sectional area of the weld becomes larger than the size of the ball (i.e., approximately the same as the size of the pocket), and the injection molding is performed. At this time, the bonding force between the joining surfaces of the resin streams is increased.
For this reason, even when the rolling bearing is used in a state of receiving a moment load, the resin cage is hardly broken by tension.

  The position of the gate is adjusted so that a weld line appearing on a predetermined surface of the cage is inclined at an angle of 17 ° or more with respect to the axis of the annular cage, or a weld having a relatively large cross-sectional area is formed. At this time, the formation position of the weld formed across the concave circular curved bottom surface and the end surface of the retainer body is also adjusted. That is, the inclination angle and cross-sectional area of the weld are adjusted depending on whether the weld is formed at a portion where the distance from the end face of the retainer body is wide or at a position where the weld is narrow.

  Further, if the resin crown retainer is made of polyetheretherketone (hereinafter, abbreviated as PEEK) resin, such a resin is employed because sufficient heat resistance and mechanical strength are provided. Is preferred.

  In addition to selecting the type of resin as described above, if the crown-made resin cage is made of fiber-reinforced resin, more sufficient heat resistance and mechanical strength are provided. It is preferable that the fiber-reinforced resin molded product contains 20 to 40% by mass of carbon fiber because heat resistance and mechanical strength are sufficiently improved.

  By adjusting the position of the gate portion, the resin-made retainer made of an injection molded body can be provided by adjusting the position and the inclination angle of the weld portion and the size of the weld area cross-sectional area associated therewith. .

  Further, in order to adjust the cross-sectional area of the weld portion to the predetermined position, it is preferable that the position of the gate portion be as close as possible to the edge of the crown-shaped retainer body in the axial direction. An outer peripheral side or an inner peripheral side edge disposed near one or more gate portions is composed of two surfaces intersecting the outer peripheral surface or the inner peripheral surface and an end surface of the cage facing the wall surface of the pocket. Provided on edges without chamfers. Thereby, the degree of freedom in selecting the position of the gate portion can be increased, and the gate portion as large as possible can be brought closer to the bottom of the pocket. The above-mentioned gate portion is preferable if it is a trace where the tunnel gate is arranged, since it becomes a gate portion without gate burrs.

  If a rolling bearing with any one of the above resin-made cages is constructed, the rolling bearing with a resin-made cage that has high weld strength and high durability even when subjected to vibration and a large bending moment load. Become. Such a rolling bearing can be applied, for example, for supporting a crankshaft in an engine device.

  In addition, in order to manufacture the above-mentioned resin-made crown type cage efficiently and with stable quality, a plurality of pockets for rotatably housing the rolling elements of the rolling bearing are arranged at equal intervals in the circumferential direction of the annular cage body. A method for manufacturing a resin cage provided by injection molding, wherein one or more weld portions are formed across the wall surface of the pocket and the surface of the cage facing the wall surface, and The crown holder made of resin so that a weld line appearing on the surface of the cage adjacent to the wall surface of the weld portion extending inward is a weld line inclined at an angle of 17 ° or more with respect to the axis of the annular cage. To manufacture.

  Further, the weld portion satisfies the ratio of the fracture load of the cage to the weld area cross-sectional area and the break elongation represented by the following formula (3) and the cross-sectional area ratio of the weld portion and the ball represented by the following formula (3). As described above, it is preferable to use a method for manufacturing a crown-shaped resin cage in which the gate is disposed close to the outer peripheral surface side or the inner peripheral surface side edge of the crown-shaped cage main body.

(3) W / (π (Da / 2) ² ) ≧ 0.15
(Where W is the weld area cross-sectional area (mm ² ), Da represents the diameter (mm) of the ball housed in the pocket, and (π (Da / 2) ² ) is the cross-sectional area of the ball in the diameter direction ( mm ² ).)

(4) 3 <(L / E ³ ) / 100 <19
(In the formula, E indicates the elongation (mm) of the crown type cage in the breaking direction due to the tensile breaking load, and L is the breaking load (N) / weld section cross-sectional area (mm ² ).)

  By arranging the gate portion close to the outer peripheral surface side or the inner peripheral surface side edge of the crown-shaped cage main body as described above, a predetermined cross-sectional area satisfying Expressions (3) and (4) is obtained. A weld portion is formed across the concave bottom surface of the pocket and the end surface of the retainer body, and has a high rupture strength of the weld and excellent durability even when subjected to vibration or a large bending moment load. Vessels can be manufactured efficiently.

  According to the present invention, a weld line inclined at an angle of 17 ° or more with respect to the axis of the annular cage is formed on a predetermined surface of the annular cage made of a resin molded body, and the above-described predetermined mathematical formula is satisfied. By forming a welded portion having a cross-sectional area, a resin cage having a high breaking strength of the welded portion and having excellent durability even when subjected to vibration or a large bending moment load.

  Furthermore, a highly durable rolling bearing incorporating such a resin cage can be obtained, and by adjusting the arrangement of the gates during injection molding, the resin cage having the above excellent characteristics can be stabilized. There is an advantage that it can be manufactured efficiently with high quality.

FIG. 3 is a perspective view of a crown-shaped resin cage showing positions of gates and welds in Examples 1 and 2 of the first embodiment and Comparative Example 1. Main part sectional view of the ball bearing in which the cage of the first embodiment is incorporated. Perspective view of a cage according to a second embodiment. Perspective view of a cage according to a third embodiment. FIG. 2 is a plan view of the crown-type resin cage of the first embodiment. Explanatory drawing which shows the diameter Da of the ball in the VI-VI line section of FIG. Explanatory drawing showing the elongation E in the breaking direction due to the tensile breaking load in FIG. It is explanatory drawing of a gate position, (a) shows the gate from which a position differs, (b) is explanatory drawing which shows the gate from which a magnitude | size differs. FIG. 3 is a plan view of the crown-type resin cage of the first embodiment. FIG. 9 is an enlarged view of a section taken along line XX FIG. 4 is a plan view of a crown-type resin cage according to a second embodiment. FIG. 11 is an enlarged view of a cross section taken along line XII-XII in FIG. 11. Top view of resin crown retainer of Comparative Example 1 FIG. 13 is an enlarged view of a cross section taken along line XIV-XIV in FIG. 13. It is explanatory drawing of the tension test of a cage, (a) is a front view of a test device, (b) is bb sectional drawing of (a). (A) Explanatory drawing which shows the relationship between the shape of the pocket of a cage, and the variable used for Numerical formula (A) and Numerical formula (B), (b) is bb sectional drawing of (a). Chart showing the relationship between weld line angle and breaking strength Explanatory drawing of cage rotation test Drawing substitute photograph showing the axial cross section of the pocket bottom of the cage

Hereinafter, first to third embodiments of the present invention will be described with reference to the accompanying drawings.
Fig As shown in 1,2,5, crown type cage 1 of the first embodiment is to be used the crankshaft X ₁ in the engine apparatus capable of supporting rolling bearing 2, rotatable balls 3 A plurality of pockets 4 (substantially the same diameter as the balls 3) are provided at one end surface of the annular resin molded body and are arranged at regular intervals in the circumferential direction, and the wall surface 4a and a crown facing the wall surface are formed. One or more welds A ', B' or C 'are formed over the end face 1a which is the surface of the mold holder 1, and the welds A', B 'or C' extend inward from the wall surface 4a of the pocket 4. The weld lines appearing on the surfaces (inner and outer peripheral surfaces) of the cage adjacent to the wall surface 4a of the above are inclined at an angle θ ₁ , θ ₂ or θ ₃ of 17 ° or more with respect to the axis X of the cage. .

  The illustrated weld portions A ′, B ′ or C ′ are formed corresponding to the gate portions A, B or C, respectively, and are schematically shown collectively to compare and explain their positional relationship. Is shown in Incidentally, the gate portions A, B, and C are traces where the gate into which the resin melted during the injection molding flows is disposed, and can be observed also on the surface of the processed injection molded article.

Among the gate portions A, B, and C, the gate portions A and C are respectively disposed at predetermined positions near the pocket 4 on the inner peripheral surface of the retainer main body, and seven gate portions A and C are provided. Are formed at seven positions at positions corresponding to.
In addition, the gate portion B is one that is disposed on the outer peripheral surface of the retainer main body, and the corresponding weld portion B ′ is also formed only at one predetermined position.

The weld line appears on the inner peripheral surface 1b and the outer peripheral surface 1c of the retainer body adjacent to the wall surface 4a (bottom surface) of the weld portion extending from the wall surface 4a (bottom surface) of the pocket 4 to the inside.
The weld line is inclined at an angle of 17 ° or more with respect to the axis X of the cage on the inner peripheral surface 1b or the outer peripheral surface 1c.

  In addition, even when the entire weld line does not appear on the surface of the actual resin molded product, the inclination angle of the line connecting both ends of the axis X of the weld line that appears on the inner peripheral surface 1b or the outer peripheral surface 1c of the annular cage. By confirming the above, it can be determined whether or not the above-mentioned expected effects can be obtained.

  As shown in FIG. 3, the resin-made cage 7 of the second embodiment includes a ball (not shown) of a rolling element in a circumferential direction of the annular cage 7 made of a rectangular plate-shaped material of a resin molded body. This is a ball bearing cage 7 in which circular hole-shaped pockets 8 rotatably held are formed at equal intervals.

In the second embodiment, weld lines appearing on the inner peripheral surface and the outer peripheral surface of the surface of the retainer 7 of the weld portion D 'extending from the wall surface of the pocket 8 are formed at two places around the pocket 8. , each weld line is inclined at 17 ° or an angle theta ₄ with respect to the axis X of the cage.

  As shown in FIG. 4, the resin cage 9 of the third embodiment includes substantially rectangular hole-shaped pockets 10 that rotatably hold rolling elements (not shown) at equal intervals in the circumferential direction. It is a cage 9 of the formed roller bearing.

Also in the third embodiment, the weld lines appearing on the inner and outer peripheral surfaces of the retainer surface of the weld portion E ′ extending from the wall surface of the pocket 10 to the inside are located at two places around the pocket 10 facing in the axial direction. are formed, each of the weld line is inclined at 17 ° or an angle theta ₅ with respect to the axis X of the roller bearing.

  In the cage for roller bearings as well, by forming the end surface 10a of the pocket 10 having a substantially rectangular hole shape into a cylindrical surface or a spherical shape with a radius R, the area in contact with the flow of the resin material during molding is smaller than that of a flat surface. As a result, the curved surface becomes larger, and the resin flow receives a corresponding flow resistance.

  Since the velocity of the flow of the resin material passing between the plane and the curved surface in the cavity is different between the plane side and the curved surface side, the shape of the tip of the resin flow also becomes inclined, and the ends of the resin flow collide with each other. The inclination angle of the weld to be formed increases.

In this manner, the angle theta ₅ of weld lines formed in the cage for a roller bearing of the third embodiment, as in the first embodiment and the ball bearing retainer of the second embodiment, the roller axis of the bearing It is easy to be formed in a state inclined to 17 ° or more with respect to X.

  Further, in each of the first to third embodiments, the weld portion has a cross-sectional area ratio between the weld portion and the ball represented by the following formula (1) and a hold against the weld cross-sectional area and the breaking elongation represented by the formula (2). The predetermined cross-sectional area that satisfies the ratio of the breaking load of the container is arranged at a predetermined position so as to have a predetermined cross-sectional area across the concave curved wall surface 4a of the pocket 4 and the end surface 1a of the retainer body. ing.

(1) W / (π (Da / 2) ² ) ≧ 0.15
(Where W is the weld area cross-sectional area (mm ² ), Da represents the diameter (mm) of the ball housed in the pocket, and (π (Da / 2) ² ) is the cross-sectional area of the ball in the diameter direction ( mm ² ).)

(2) 3 <(L / E ³ ) / 100 <19
(In the formula, E indicates the elongation (mm) of the crown type cage in the breaking direction due to the tensile breaking load, and L is the breaking load (N) / weld section cross-sectional area (mm ² ).)

  The symbols Da, W, and E in the above equations are shown in FIG. 6, FIG. 16B, or FIG.

  The weld area cross-sectional area referred to in the present invention is similar to the actual area of a three-dimensional fracture surface observed in a tensile fracture test, and at least one weld line appearing on the surface of the cage 1 as an injection molded body. This is a cross-sectional area calculated from a plane passing through at least two.

The left side of Equation (1) above is the weld area cross-sectional area W (mm ² ) and the cross-sectional area ratio of the ball.
Similarly, Expression (2) is [(breaking load (N) / weld section cross-sectional area (mm ² )) / (cubic value of elongation (mm) in the breaking direction of crown-shaped cage due to tensile breaking load] / The value of 100 indicates that it is more than 3 and less than 19. The value of the tensile breaking load (or breaking load) is measured by a tensile test described later.

  The positions of the welded portions A ', B', C 'formed over the concave curved wall surface 4a of the pocket 4 and the end surface 1a of the retainer 1 so that these values are within the set values. Is specified, and the positions of the gate portions A, B, and C are adjusted so as to be specified at such a position.

  The circumferential positions of the welded portions A ′, B ′, and C ′ formed on the crown-shaped retainer body are arranged at substantially the same distance from the positions of the gates A, B, and C. The positional relationship is the same even when one or a plurality of gate portions are provided, and the same number of weld portions are formed corresponding to the number of gate portions.

  The axial positions (heights in the vertical direction in FIG. 1) of the gate portions A, B, and C of the crown-shaped retainer main body correspond to the concave circular curved wall surface 4a of the pocket 4 and the end surface 1a of the retainer 1 main body. This is related to moving the formation position of one or more weld portions A ′, B ′, and C ′ that are straddled closer to or away from the central portion (the deepest portion of the concave circular curved surface) of the wall surface 4a of the pocket 4.

  That is, if the height of the gate portions A, B, and C in the axial direction is high, the weld portions A ′, B ′, and C ′ approach the center of the concave curved wall surface 4a of the pocket 4, and the gate portions A, If the heights of B and C are reduced to be closer to the center of the wall 4a of the pocket 4, the welds A ', B' and C 'are similarly moved away from the center of the wall 4a of the pocket 4.

As shown in FIG. 8, for example, when the gate portion F (F ₁ or F ₂ ) is provided, the inner peripheral surface side edge 1 d disposed in the vicinity of the gate portion F is attached to the inner peripheral surface 1 b and the wall surface 4 a of the pocket 4. It is preferable to provide the edge 1d without chamfering, which is composed of two surfaces that intersect with the end surface 1a of the opposing cage. Further, it is preferable that the outer edge of the outer peripheral surface is also provided at an edge without chamfering, which is composed of two surfaces intersecting the outer peripheral surface and the end surface 1a of the retainer facing the wall surface 4a of the pocket 4.

In this case, the height of the gate portion is set at a position (gate F ₂ ) that is as low as possible relative to a position (gate F ₁ ) having the chamfered edge 1 d ′ (FIG. 8A). Accordingly, the weld portion can be moved away from the center of the wall surface 4a of the pocket 4 accordingly. This is apparent from the positional relationship between the gate portions A and C and the weld portions A ′ and C ′ in the first embodiment.

Also, as shown in FIG. 8B, providing an edge 1d without chamfering instead of the chamfered edge 1d 'helps to increase the area of the gate portion itself. That is, it is possible to increase the gate G ₁ as the gate G _2, or slows the cooling rate of the resin material by increasing the inflow of molten resin material, or achieving uniform cooling rate, the weld Can be increased in strength. Furthermore, even in a small cage, it is possible to secure a sufficient gate inflow diameter and set a relatively free gate position.

  By selectively arranging the gate position on the inner peripheral surface 1b side or the outer peripheral surface 1c side (FIG. 1) of the column portion between the adjacent pockets 4, the molten resin derived from the shape of the pocket 4 of the ball bearing is formed. A gradient can be generated in the axial flow velocity, so that the weld line has a certain angle with respect to the bottom surface of the cage 1, that is, with respect to the axis X of the annular cage of the rolling bearing.

Further, by disposing the gate at a position shifted from the center of the pillar portion, the weld line can be shifted from the bottom of the pocket having the smallest thickness, and the sectional area of the weld portion can be increased.
In this manner, the cross-sectional area of the weld portion can be increased in the cross section of the cage 1 and the load component perpendicular to the weld surface due to the axial load applied to the cage due to the inclination angle can be reduced.

  Note that the number of pockets in the above-described embodiment is not limited to seven as shown in FIG. 1 and can be changed as appropriate according to the application of the rolling bearing.

  In the embodiment, since the strength of the weld portion is improved, it is possible to provide a weld line across the wall surfaces of all the pockets and the surface of the cage facing the wall surface. A good cage having high dimensional accuracy such as circularity can be obtained, and the rotational accuracy of a rolling bearing incorporating the same can be improved.

  Further, it is preferable that the chamfers of the edges of the cages 1, 7, 9 are provided on both sides (the inner peripheral surface and the outer peripheral surface) of the end surfaces. This is to reduce the number of dies to reduce the manufacturing cost and to prevent the occurrence of burrs (that is, the phenomenon that resin enters the gaps between the dies). In the embodiment, the gate side is not chamfered on purpose to adjust the gate position and secure the cross-sectional area.

  In addition, in order to reduce material costs, prevent sink marks, and prevent variations in the cooling rate of the resin and the reduction in weld strength, in many cases, meat stealing is provided. However, the resin cage of the present invention dares to steal meat. By not providing this, it is possible to cope with the low fluidity of the resin material such as PEEK and to expand the sectional area of the weld line. In addition, it has been confirmed that the cage using the PEEK of the below-described reference example having the meat stealing cannot withstand the rotation test and is broken.

  As the resin molding material of the resin cage used in the present invention, any resin can be used as long as it has sufficient heat resistance and mechanical strength as the material of the cage. Hereinafter, common names of such resins are listed, and abbreviations are also written in parentheses. For example, polyamide 6 (PA6) resin, polyamide 6-6 (PA66) resin, polyamide 6-10 (PA610) resin, polyamide 9-T (PA9T) resin, polymetaxylene adipamide (polyamide MXD-6) resin, etc. Injection-moldable fluororesin such as polyamide (PA) resin, polytetrafluoroethylene / perfluoroalkylvinyl ether copolymer (PFA) resin, polyethylene (PE) resin, polycarbonate (PC) resin, polyacetal (POM) resin, Polyphenylene sulfide (PPS) resin, polyetheretherketone (PEEK) resin, polyamideimide (PAI) resin, polyetherimide (PEI) resin, and the like can be given. Each of these synthetic resins may be used alone, or may be a polymer alloy in which two or more kinds are mixed. In particular, PEEK resin is preferable because it is a molding material having more sufficient heat resistance and mechanical strength for the cage.

  Further, the resin forming the resin crown type retainer may include a fibrous reinforcing material, for example, a well-known material such as glass fiber, carbon fiber, metal fiber, polyamide fiber, polyimide fiber, and mineral fiber. A fibrous reinforcement may be included. Among such fibrous reinforcing materials, in order to maintain the mechanical strength of the bearing material well, and to avoid a decrease in the fluidity of the resin material, it is preferable to mix glass fibers or carbon fibers, particularly By mixing about 20 to 40% by mass of the carbon fiber in 100 parts by mass of the resin molded body, a sufficient improvement in mechanical strength is recognized.

[Example 1-3, Comparative Example 1]
An annular cage 1 having the same form as the embodiment shown in FIGS. 1 and 2 was manufactured by injection molding, and a polyetheretherketone (PEEK) resin was used as a resin molding material.
As shown by reference numeral A in FIGS. 1 and 9 (Example 1) or reference numeral C in FIGS. 1 and 13 (Comparative Example 1), in Example 1 and Comparative Example 1, the gate portion is located on the inner peripheral surface side. In Example 3, the gate portion was similarly set at a position slightly closer to Comparative Example 1 in Example 3.
Further, as shown by reference numeral B in FIG. 1 and FIG. 11 (Example 2), in Example 2, the gate portion was installed at one place on the outer peripheral surface side.

As a result, in Example 1 and Comparative Example 1, as shown by reference numeral A ′ in FIGS. 1 and 9 (Example 1) or C ′ in FIG. It was formed at predetermined seven places on the peripheral surface side, and also in Example 3, weld parts were formed at seven places.
Further, as shown by reference numeral B ′ in FIGS. 1 and 11 (Example 2), in Example 2, the weld portion was formed at one position on the outer peripheral surface side.

[Comparative Example 2]
Using a polyamide 6-6 (PA66) resin as a molding material, a crown type retainer having the same size as that of the embodiment was manufactured by injection molding. At this time, the position of the gate portion was set at an intermediate portion between a pair of adjacent pockets, but the weld portion was formed at the center of the bottom surface of the pocket.

[Reference example]
A crown type cage made of a commercially available polyetheretherketone (PEEK) resin and having the same form as that of the embodiment was used.

Regarding the above Example 1-3, Comparative Example 1-2 and Reference Example, the inner peripheral surface and the outer peripheral surface of the retainer main body adjacent to the wall surface (bottom surface) of the weld portion extending inward from the wall surface (bottom surface) of the pocket. weld angle of inclination relative to the axis of the cage of lines appearing (example 1 theta ₁ in FIG. _10, the embodiment 2 theta _2, Comparative example 1 in FIG. 12 was. that shown in theta ₃ in FIG. 14) was measured.

  A deep groove ball bearing 6202 (inner diameter 15 mm, outer diameter 35 mm, width 11 mm) was manufactured by incorporating the cages of Example 1-3, Comparative Example 1-2, and Reference Example, respectively. The test was performed.

In addition, the ball diameter of the deep groove ball bearing (excluding the reference example) was 6.35 mm, and the ball cross-sectional area was 31.67 mm ² . The results of the measurement of the inclination angle of the weld line and the results of the tensile test are summarized in Table 1 below.
In addition, the values of the above formula (1) and the number (2) were calculated from the measured values, and are also shown in Table 1 as well as “not broken in the rotation test” or “broken in the same test” described later. It was evaluated in two steps.

[Tensile test]
As shown in FIGS. 15 (a) and 15 (b), tensile jigs 6 and 6 ′ having semicircular jigs 5 and 5 ′ are arranged in a pair at the upper and lower sides, and an example, a comparative example, or a reference example is provided. The cage 1 is fitted so that the weld portion is arranged horizontally (at 3 o'clock and 9 o'clock in the ring of the crown type retainer in FIG. 15A), that is, the weld portion is The jigs 5 and 5 ′ are set so as to coincide with the mating surfaces, and tensile force is applied vertically at a tensile speed of 10 (mm / min) to determine the breaking load (N) and the elongation (mm) in the breaking direction. It was measured.

  The semicircle jigs 5 and 5 'were performed with the radius of the circumferential portion being 97% of the inner radius of the cage. Further, at least one weakest portion was arranged at a position perpendicular to the tensile direction. The water absorption of the resin cage is within 0 to 3%, and the cage shape of the embodiment has an inner diameter of 22.2 mm, an outer diameter of 27.8 mm, and a minimum ring portion with a ball pitch circle diameter (ball PCD). The thickness was 1.5 mm, and the maximum thickness of the ring portion in the ball PCD was 6.53 mm.

As shown in FIG. 16A, the length L of the weld line is expressed by the following equation (A) from the cross-sectional shape of the pocket at an arbitrary position of the ball bearing.
This equation (A) is based on the relationship of r + t = (L + r) cos θ between r: pocket diameter (radius), t: bottom wall thickness, L: weld length, and θ: weld angle. This is modified to make L on the left side.
L = {t + r (1-cos θ)} / cos θ (A)

  By integrating the weld length L measured as described above in the radial direction of the cage, an approximate value of the sectional area of the weld portion can be calculated. The length in the radial direction here is a predetermined value calculated by the outer diameter-inner diameter of the annular cage, and does not relate to the weld angle.

Further, the cross-sectional area of the weld portion can be simply calculated by a calculation method exemplified below, and the calculated value is shown in Table 1.
For example, using the symbols shown in FIGS. 16A and 16B (see also FIG. 19), the sectional area W of the weld portion is calculated by the following formula. Note that g and e in the formulas indicate the length of one edge of the bottom of the cage cut out in the axial and radial directions by chamfering. In Example 1, L = 2.221 mm, e = 0.620, f = 2.267, and g = 0.595 by actual measurement.
W = L × (f + e) − (ex × g) / 2 (B)
Substituting the numerical value of Example 1 into the above formula (B),
W = 2.221 × (2.267 + 0.620) − (0.620 × 0.595) / 2
= 6.412-0.1845
= 6.2275 (6.23 when rounded to two decimal places)

[Rotation test]
The durability of the rolling bearing 2 incorporated in the rotation test device shown in FIG. 18 was examined.
The rotation test device is provided with a motor 12 fixed to a substrate 11 and a transmission 14 for transmitting the rotational force of the motor 12 via a conduction belt 13, and a test rolling bearing 2 mounted on an output shaft 15. The moment 16 acting as the bending force of the shaft is applied by the weight 16 attached to the tip of the cantilever.

  Using this device, a deep groove ball bearing 6202 incorporating the cage of the example, comparative example or reference example is mounted, and a rotation test at a rotation speed of 6000 rpm for 20 minutes with a moment load of 5.88 N · m applied. Was carried out in a non-lubricated condition. As a result, it was found that only Example 1-3 could withstand without breaking, and this result is also shown in Table 1.

  As is clear from the results shown in Table 1, Examples 1 (29.96) and Example 3 (29.96) in which the inclination angle (weld line angle) of the weld line with respect to the retainer axis is 17 ° or more. °) and Example 2 (26.77 °), the values of Expression (1) and Expression (2) are within the above-mentioned predetermined ranges, and Examples 1 to 3 have excellent results with respect to the breaking load. As shown in the figure, it was confirmed that the weld portion formed by injection molding was hardly broken because the weld portion was formed with an appropriate inclination angle and preferably an appropriate cross-sectional area.

  Also, as shown in FIG. 17, the weld line angle is 26 compared to the breaking load (269.94N) of Comparative Example 1 in which the inclination angle of the weld line with respect to the retainer axis is less than 17 ° (16.0 °). The breakage load (398.19N) of Example 2 at 0.77 ° and the breakage load (average value) of Examples 1 and 3 at a weld line angle of 29.96 ° both had an inclination angle of 17 ° or more. The tendency of increase in was linear at a steep angle, and the cage of Example 1-3 did not break in the rotation test. From these facts, it was recognized that, when the inclination angle was 17 ° or more, of the load components applied to the cage, the load component perpendicular to the weld surface due to the axial load could be sufficiently reduced.

  Thus, in Example 1-3, a resin cage excellent in durability even under a large bending moment load was obtained, and a rolling bearing excellent in durability incorporating the same was obtained.

The resin cage of the rolling bearing such as the resin crown type retainer of the present invention and the rolling bearing having the same can be used for various types of construction machinery, industrial machinery, and other general bearings. It is capable of supporting a relatively high-speed rotating shaft, such as a rolling bearing for supporting a crankshaft in an engine device to be used, and is applicable to applications that are required to withstand vibration and moment loads. As well as such applications, rolling bearings can withstand severe vibrations and loads that incline the rotating shaft, withstand insufficient supply of lubricating oil, and prevent the generation of abrasion powder that may cause quality problems. Widely applicable.
Further, a resin-made crown type retainer molded of engineering plastic such as PEEK is suitable for use in a rolling bearing that rotates at high temperature and at high speed.

DESCRIPTION OF SYMBOLS 1 Crown type retainer 1a End surface 1b Inner peripheral surface 1c Outer peripheral surface 1d Edge 2 Rolling bearing 3 Ball 4, 8, 10 Pocket 4a Wall surface 5, 5 'Semicircle jig
6, 6 'Tensile jig 7, 9 Cage 11 Substrate 12 Motor 13 Transmission belt 14 Transmission 15 Output shaft 16 Weights A, B, C Gate parts A', B ', C' Weld part P Center point X Axis

Claims (11)

  A plurality of pockets for rotatably housing the rolling elements of the rolling bearing are arranged at equal intervals in a circumferential direction of an annular retainer made of a resin molded body, and are adjacent to the wall surface of a weld portion extending inward from the wall surface of the pocket. The weld line that appears on the surface of the cage is a weld line that is inclined at an angle of 17 ° or more with respect to the axis of the cage.   The resin cage for a rolling bearing according to claim 1, wherein the annular cage is a crown type cage. A plurality of pockets for rotatably accommodating the rolling elements of the rolling bearings are arranged at equal intervals in a circumferential direction of a crown-shaped retainer made of a resin molded body, and a weld portion extending inward from a wall surface of the pocket is provided in the pocket. A cross-sectional area ratio of a weld portion and a ball or a roller formed over a wall surface and a surface of a cage facing the wall surface and represented by the following formula (1) and a weld cross-sectional area represented by a formula (2) A resin cage for a rolling bearing having a predetermined sectional area satisfying a ratio of a breaking load of the cage to a breaking elongation.
(1) W / (π (Da / 2) ² ) ≧ 0.15
(Where W is the weld area cross-sectional area (mm ² ), Da represents the diameter (mm) of the ball housed in the pocket, and (π (Da / 2) ² ) is the cross-sectional area of the ball in the diameter direction ( mm ² ).)
(2) 3 <(L / E ³ ) / 100 <19
(In the formula, E indicates the elongation (mm) of the crown type cage in the breaking direction due to the tensile breaking load, and L is the breaking load (N) / weld section cross-sectional area (mm ² ).)   The resin cage for a rolling bearing according to any one of claims 1 to 3, wherein the resin molded body is a resin molded body made of an injection molded body.   The resin cage for a rolling bearing according to claim 4, wherein the resin molded body is a fiber-reinforced resin molded body.   The resin cage for a rolling bearing according to claim 5, wherein the fiber-reinforced resin molded product is a resin molded product made of a fiber-reinforced resin composition containing 20 to 40% by mass of carbon fibers.   The resin cage for a rolling bearing according to any one of claims 4 to 6, wherein the resin molded body is made of a polyetheretherketone resin.   The resin-made cage has an outer peripheral surface side or an inner peripheral surface side edge disposed in the vicinity of one or more gate portions, and an end surface of the cage facing the outer peripheral surface or the inner peripheral surface and a wall surface of the pocket. The resin cage for a rolling bearing according to any one of claims 1 to 7, wherein the main body is a crown-shaped cage main body provided at an edge without chamfering composed of two intersecting surfaces.   9. The resin cage for a rolling bearing according to claim 8, wherein the gate portion is a trace where a tunnel gate is arranged.   A rolling bearing comprising the resin cage of the rolling bearing according to claim 1.   A rolling bearing for supporting a crankshaft in an engine device, comprising a resin cage of the rolling bearing according to claim 1.