Cages and ball bearings

Abstract

To efficiently perform reinforcement by a metallic material, in a cage in which an annular part and a plurality of horned parts are formed by insert molding for integrating a synthetic resin and the metallic material together, in which a ring reinforcement of the metallic material is arranged in the annular part, and in which a reinforcing projection piece of the metallic material is arranged on the horned part.SOLUTION: A reinforcing projection piece 15 has a solid plate part that is solidly extended to one side in an axial direction from a ring reinforcement 14. The solid plate part reaches one side and the other side in a circumferential direction of a horned part 8. A synthetic resin 9 coats the solid plate part from both sides in a radial direction and both the sides in the circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cage and a ball bearing, and more particularly to a one-piece cage with horns, such as a crown cage, provided in a ball bearing. [Background technology]

[0002] In rolling bearings that require high speed rotation in high temperature environments such as automobiles and machine tools, horn-shaped cages made of synthetic resins are used, which are less aggressive to rolling elements and have excellent lubricity. However, horn-shaped cages made of synthetic resins are less resistant to deformation due to centrifugal force compared to metal ones, so when used under high speed rotation, the cantilever-shaped horns are easily deformed radially outward due to centrifugal force.

[0003] In recent years, with the improvement of performance and miniaturization of automobiles and the like, there is a trend for bearings to rotate at higher speeds, take up less space, and use at higher temperatures, and there is a concern that a cage made of synthetic resin will not be resistant to deformation due to centrifugal force. In other words, if the horns are deformed radially outward by centrifugal force, the area on the tip side and inner diameter side of the horns may come into contact with the rolling elements, hindering the rolling of the rolling elements, or the cage may suffer abnormal wear or cracks, or may interfere with the inner peripheral surface of the outer ring, preventing the bearing from rotating normally without damage. When such concerns exist, cages formed by insert molding, which integrates synthetic resin and metal material, are used.

[0004] The cage disclosed in Patent Document 1 includes a metal material having a reinforcing ring that is continuous around the entire circumference and a plurality of reinforcing projections that protrude from the reinforcing ring to one side in the axial direction. The reinforcing ring is disposed in the annular portion of the cage and is integrated with the synthetic resin that forms the annular portion. The plurality of reinforcing projections are disposed in horns of the cage and are integrated with the synthetic resin that forms the horns. The annular portion of the cage has improved bending rigidity and torsional rigidity against centrifugal force due to the reinforcing ring made of metal that is more rigid than synthetic resin. In particular, the reinforcing ring has an L-shaped cross section around the entire circumference, thereby enhancing the reinforcing effect of the annular portion. Furthermore, the reinforcing projection is a reinforcing projection that forms one side of the L-shaped cross section, thereby enhancing the reinforcing effect of the horn.

[0005] The reinforcing piece and the reinforcing ring each have a through hole that is filled with synthetic resin to bond the synthetic resin and the metal together. Before the metal is inserted, the metal is dipped in an adhesive to strengthen the bond between the synthetic resin and the metal. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-46069 A (Figures 1 to 4, paragraphs 0002 to 0027) Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the cage of Patent Document 1, the reinforcing protrusions made of metal are circumscribed on the synthetic resin that forms the horns and are arranged on the outer diameter of the horns, maximizing the outer diameter of the reinforcing protrusions, which is disadvantageous for the measure to reduce the mass of the horns (reinforcing protrusions) and reduce the centrifugal force acting on the horns.

[0008] In addition, a large through hole is formed in the center of the circumferential width of the reinforcing piece to allow for an integral bond with the synthetic resin, and the mass of the reinforcing piece is reduced by the formation of the through hole, but on the other hand, there is little solid part where the reinforcing piece extends continuously in the axial direction from the reinforcing ring, and the reinforcing efficiency of the reinforcing piece is not good. The reduction in reinforcing efficiency due to the formation of the through hole is the same for reinforcing rings made of metal.

[0009] In addition, the reinforcing protrusion is bonded to the synthetic resin at its circumferential contact with the synthetic resin that forms the horn, but this requires an adhesive application process, which makes manufacturing inefficient. If the bond comes off, the reinforcing effect of the reinforcing protrusion will be lost.

[0010] Therefore, the problem that this invention aims to solve is to efficiently provide reinforcement with metal material in a retainer in which an annular portion and multiple horns are formed by insert molding that integrates synthetic resin and metal material, a reinforcing ring made of metal is arranged in the annular portion, and reinforcing protrusions made of metal are arranged in the horns. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a cage comprising an annular portion and a plurality of horns protruding from the annular portion to one axial side at equal intervals in the circumferential direction, the spaces between adjacent horns in the circumferential direction being pockets for accommodating rolling elements, the annular portion and the plurality of horns being formed by insert molding that integrates a synthetic resin with a metal material, the metal material integrally having a reinforcing ring continuing around the entire circumference and a plurality of reinforcing projections protruding from the reinforcing ring to one axial side, the reinforcing ring being disposed in the annular portion, and the plurality of reinforcing projections being respectively disposed in the horns, the reinforcing projections having a solid plate portion extending solidly from the reinforcing ring to one axial side, the solid plate portion extending to one circumferential side and the other circumferential side of the horns, and the synthetic resin covering the solid plate portion from both radial and circumferential sides.

[0012] According to the above configuration, the solid plate portion of the reinforcing protrusion extends solidly from the reinforcing ring portion towards one axial side, and extends to one and the other circumferential sides of the horn, and is covered from both radial and circumferential sides with synthetic resin.Therefore, the solid plate portion which has a wide circumferential width and has no through holes is integrated with the synthetic resin to efficiently reinforce the horn, and ultimately, reinforcement by metal material can be efficiently achieved.

[0013] More specifically, the reinforcing ring has a base plate portion that is solidly connected around the entire circumference and extends in the radial direction, the base plate portion extends around the inner diameter side and the outer diameter side of the annular portion, and the entire base plate portion is embedded in the synthetic resin. In this way, the base plate portion having a wide radial width and no through holes can be integrated with the synthetic resin to efficiently reinforce the annular portion. In addition, in the circumferential region where the horn and the annular portion are present, the reinforcing protrusion made of metal and the reinforcing ring form an L-shaped cross section without a through hole, so that the reinforcement can be particularly efficiently performed.

[0014] The reinforcing protrusions may be continuous with the inner circumference of the reinforcing ring, so that the reinforcing protrusions are disposed closer to the central axis (inner diameter side) of the cage, and centrifugal force acting on the solid plate portion can be suppressed, compared to when the reinforcing protrusions are continuous with the outer circumference of the reinforcing ring.

[0015] The reinforcing projection may have a rib portion bent from the solid plate portion so as to be discontinuous with the reinforcing ring and abut against a side surface on one axial side of the reinforcing ring in the axial direction. In this way, the rib portion and the side surface on one axial side of the reinforcing ring abut against each other to resist centrifugal force, so that the bending rigidity of the reinforcing projection against centrifugal force can be increased. In addition, since the rib portion is formed by bending from the solid plate portion, it is possible to form the rib portion larger and increase the bending rigidity of the reinforcing projection against centrifugal force, compared to when the rib portion is formed by recessing the continuous portion between the reinforcing ring and the solid plate portion.

[0016] The rib portion may be formed on one or both circumferential sides of the reinforcing piece, so that the rib portion and the reinforcing ring butt against each other on one or both circumferential sides of the reinforcing piece, thereby further increasing the bending rigidity of the reinforcing piece against centrifugal force.

[0017] The reinforcing projection may be formed to be thinner than the thickness of the base portion of the reinforcing ring, thereby reducing the mass of the reinforcing projection and the centrifugal force acting on the reinforcing projection.

[0018] The rib portion may be shaped so that it becomes shorter in the radial direction toward one side in the axial direction. In this way, the mass of the rib portion is suppressed at the tip side of the reinforcing projection without reducing the abutment portion between the rib portion and the reinforcing ring, so that the centrifugal force acting on the reinforcing projection can be further suppressed.

[0019] The reinforcing projections may have exposed ends that are exposed from the synthetic resin toward one axial side, and the entire remaining portions of the reinforcing projections excluding the exposed ends may be embedded in the synthetic resin. In this way, insert molding can be performed in which the exposed ends of the multiple reinforcing projections are utilized for arranging the metal material in a mold, and most of the metal material can be covered with synthetic resin to integrate the metal material and the synthetic resin.

[0020] The reinforcing ring may have a flange portion extending in the axial direction, whereby the flange portion can further increase the rigidity of the reinforcing ring.

[0021] The flange portion may extend to the other axial side so as to have an exposed end portion that is exposed from the synthetic resin toward the other axial side, and the entire remaining portion of the reinforcing ring excluding the exposed end portion may be embedded in the synthetic resin. In this manner, insert molding may be performed in which the exposed end portion of the flange portion is utilized for arranging a metal material in a mold, and most of the metal material may be covered with synthetic resin to integrate the metal material and the synthetic resin.

[0022] The metal material may be formed of a cold-rolled steel plate. In this way, the reinforcing ring or the reinforcing protrusion can be formed by metal press processing using a die. Here, the cold-rolled steel plate refers to one that complies with the "Cold-rolled steel plate and steel strip" of the Japanese Industrial Standard (JIS G3141:2017).

[0023] The thickness of the metal material is preferably 4% to 6% of the diameter of the rolling elements. In the case of a cold-rolled steel plate, a thickness of 4% or more of the diameter of the rolling elements is sufficient to obtain the reinforcing effect of the metal material, but a thickness of more than 6% is not preferable because there is a concern that the thickness may be excessively large.

[0024] The synthetic resin may be at least one of a thermosetting resin and a thermoplastic resin.

[0025] A ball bearing comprising the retainer of the present invention, an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring, has excellent resistance to deformation of the retainer against centrifugal force, making it suitable for high-speed rotation. Effect of the Invention

[0026] As described above, by adopting the above-mentioned configuration, the present invention can efficiently provide reinforcement with metal material in a retainer in which an annular portion and a plurality of horns are formed by insert molding that integrates synthetic resin and metal material, a reinforcing ring made of metal material is arranged in the annular portion, and reinforcing protrusions made of metal material are arranged in the horns. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a cross-sectional view showing a ball bearing according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a side view showing a cage according to a first embodiment of the present invention, viewed from one axial side; [Diagram 3] Cross-sectional view of line III-III in Figure 2 [Figure 4] FIG. 1 is a partial perspective view of a metal material according to a first embodiment; [Diagram 5]Cross-sectional view showing the state before and after deformation of the cage analysis example shown in Figure 2 [Figure 6] 4A and 4B are cross-sectional views showing the state of a cage of a comparative example before and after deformation. [Figure 7] FIG. 11 is a partial cross-sectional view showing a cage according to a second embodiment of the present invention. [Figure 8] FIG. 13 is a partial perspective view of a metal material according to a second embodiment. [Figure 9] FIG. 9(a) is a schematic diagram showing a cross section of a workpiece used in the manufacturing process of the metal material shown in FIG. 8 taken along line AA in FIG. 9(b), and FIG. 9(b) is a side view showing the workpiece in FIG. 9(a) from one axial side. [Figure 10] (a) is a schematic diagram showing the workpiece in the next process in a cross section taken along line AA in (b) of the same figure, and (b) is a side view showing the workpiece in (a) from one axial side. [Figure 11] (a) is a schematic diagram showing the workpiece in the next process in a cross section taken along line AA in (b) of the same figure, and (b) is a side view showing the workpiece in (a) from one axial side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] A first embodiment as one example of the present invention will now be described with reference to the accompanying drawings, FIGS. 1 to 6. FIG.

[0029] 1 to 5 is a bearing component for evenly arranging multiple rolling elements 4 between an inner ring 2 and an outer ring 3 in the circumferential direction. The multiple rolling elements 4 are interposed between an inner raceway 5 formed in the inner ring 2 and an outer raceway 6 formed in the outer ring 3. The rolling elements 4 are made of balls.

[0030] In Fig. 1, the central axes (not shown) of the cage 1, inner ring 2, and outer ring 3 are arranged coaxially and correspond to the bearing central axis, which is the design center of rotation of the ball bearing. Hereinafter, the central axis of the cage 1 will be simply referred to as the "central axis."

[0031] Here, the axial direction refers to a direction along the central axis. The one axial side refers to one direction in the axial direction, and is the right side in FIG. 1. The other axial side refers to the opposite direction to the one direction, and is the left side in FIG. 1. The radial direction refers to a direction perpendicular to the central axis. The radially outer side refers to a direction moving away from the central axis in the radial direction, and is the upper side in FIG. 1. The radially inner side refers to a direction approaching the central axis in the radial direction, and is the lower side in FIG. 1. The circumferential direction refers to a direction along a circumference that goes around the central axis. The one circumferential side refers to one circumferential direction, and is either the left or right direction in FIG. 2, and the other circumferential side refers to the opposite direction to the one direction.

[0032] As shown in Figures 3 to 5, the cage 1 includes an annular portion 7 extending in the circumferential direction, and a number of horns 8 protruding from the annular portion 7 to one side in the axial direction at equal intervals in the circumferential direction. The annular portion 7 and the number of horns 8 are formed by insert molding, which integrates a synthetic resin 9 and a metal material 10. The entire cage 1 is formed by insert molding.

[0033] The space between the horns 8, 8 adjacent in the circumferential direction forms a pocket 11 for accommodating the rolling element 4.

[0034] The cage 1 accommodates the rolling elements 4 in pockets 11 surrounded on three sides by circumferentially adjacent horns 8, 8 and the annular portion 7. The pockets 11 are spaces that are open radially outward, radially inward, and to one axial side. The number of pockets 11 is the same as the number N of the multiple horns 8. Each pocket 11 accommodates one rolling element 4. The cage 1 has a shape with N-fold rotational symmetry about its central axis.

[0035] The radially outer opening and the radially inner opening of the pocket 11 have a diameter that does not allow the rolling elements 4 to pass radially. The cage 1 is a crown-shaped cage that can accommodate the multiple rolling elements 4 arranged between the inner and outer raceways 5, 6 in the multiple pockets 11 by elastically deforming the multiple horns 8 to widen the opening on one axial side of the pocket 11 in the circumferential direction.

[0036] The outer diameter surface and inner diameter surface of the annular portion 7 each have a cylindrical surface extending in the circumferential direction. The outer diameter surface and inner diameter surface of the horns 8 each have the same surface as the outer diameter surface or inner diameter surface of the annular portion 7. The outer diameter and inner diameter of the cage 1 correspond to the diameter of an imaginary cylindrical surface circumscribing or inscribing the annular portion 7 and the multiple horns 8, respectively. The side surface on the other axial direction of the cage 1 consists of the side surface on the other axial direction of the annular portion 7.

[0037] The horn portion 8 has a solid base 12 that is axially connected to the annular portion 7, and a pair of claws 13a, 13b that protrude from the solid base 12 to one side in the axial direction.

[0038] The solid base 12 is continuous in the circumferential direction between the pockets 11, 11 adjacent in the circumferential direction. The pair of claws 13a, 13b consists of a first claw 13a and a second claw 13b that are spaced apart from each other in the circumferential direction. Each of the claws 13a, 13b is a cantilever beam that protrudes into the air from one axial side of the solid base 12.

[0039] A recessed space having a depth from the tip of the claw to the other axial direction is formed between the pair of claws 13a, 13b of the horn 8. This reduces the volume of the horn 8 compared to when the recessed space is filled with a resin part. Due to the reduction in the volume of the horn 8, the centrifugal force acting on the horn 8 when the cage 1 rotates is reduced, and deformation of the horn 8 due to the centrifugal force is suppressed.

[0040] The surface portion of the cage 1 that forms the pocket 11 is made of synthetic resin 9. The resin surface that forms the pocket 11 is shaped roughly along an imaginary spherical surface, and includes a contact area that defines the pocket clearance between the cage 1 and the rolling elements 4. The cage 1 and the rolling elements 4 can move relatively freely within the range of the pocket clearance. The center of the imaginary spherical surface coincides with the centers of the rolling elements 4 that are arranged on the pitch circle diameter of the multiple rolling elements 4. The resin surface that forms the pocket 11 is plane-symmetrical with respect to an imaginary plane that includes the centers and central axes of the rolling elements 4 that are arranged on the pitch circle diameter.

[0041] By pressing the pair of claws 13a, 13b axially from their tips against the rolling element 4 interposed between the inner and outer raceways 5, 6, each claw 13a, 13b is elastically deformed, widening the opening on one axial side of the pocket 11, and the rolling element 4 enters between the adjacent claws 8, 8.

[0042] The metal material 10 integrally includes a reinforcing ring 14 that is continuous around the entire circumference, and a plurality of reinforcing projections 15 that protrude from the reinforcing ring 14 to one side in the axial direction. The reinforcing ring 14 is disposed in the annular portion 7. The plurality of reinforcing projections 15 are disposed in the horn portions 8, respectively.

[0043] The metal material 10 is formed of a cold-rolled steel plate such as SPCC, SPCD, etc. The entire metal material 10 can be formed by metal press working using a die.

[0044] The thickness of the metal material 10 is 4% or more and 6% or less of the diameter of the rolling elements 4. This thickness is satisfactory for the entire metal material 10. If the thickness is 4% or more, the reinforcing effect of the metal material 10 can be obtained, but if the thickness exceeds 6%, the thickness becomes too large, which is undesirable in terms of embedding in synthetic resin and suppressing mass.

[0045] The reinforcing ring 14 comprises a base portion 16 which is continuous solidly around the entire circumference and extends in the radial direction, and a plurality of bent portions 17 which connect the base portion 16 and the reinforcing projections 15 .

[0046] No hole penetrating in the axial direction is formed in base plate portion 16. Base plate portion 16 extends over the entire circumference to the inner diameter side and the outer diameter side of annular portion 7. The inner diameter side and the outer diameter side of annular portion 7 are bounded by an imaginary cylindrical surface that bisects the difference between the inner diameter and the outer diameter of annular portion 7 in the radial direction.

[0047] The end of the inner diameter side of the substrate portion 16 is located on the inner diameter side of the annular portion 7 close to the inner diameter surface of the annular portion 7 (i.e., close to the inner diameter surface of the annular portion 7 with respect to an imaginary cylindrical surface which further bisects the difference between the aforementioned boundary and the inner diameter of the annular portion 7 in the radial direction). Similarly, the end of the outer diameter side of the substrate portion 16 is located on the outer diameter side of the annular portion 7 close to the outer diameter surface of the annular portion 7.

[0048] The bent portion 17 is a bent portion that is plastically deformed by bending the portion to be the reinforcing projection 15 toward one side in the axial direction.

[0049] The inner periphery of the reinforcing ring 14 is made of a circular plate edge of the base plate portion 16 that is continuous with the entire periphery. Therefore, the inner diameter of the reinforcing ring 14 is constant over the entire periphery. The inner diameter of the reinforcing ring 14 corresponds to the inner diameter of the metal material 10.

[0050] The outer periphery of the reinforcing ring 14 is composed of a plurality of bent portions 17 and a plurality of arc-shaped plate edges extending in an arc shape concentric with the circular plate edge between adjacent bent portions 17, 17 in the circumferential direction. The outer diameter of the reinforcing ring 14 corresponds to the diameter of an imaginary circle circumscribing the plurality of bent portions 17. The outer diameter of the reinforcing ring 14 corresponds to the outer diameter of the metal material 10.

[0051] The multiple reinforcing projections 15 are each continuous with the outer periphery of the reinforcing ring 14 at the bent portions 17. The circumferential pitch of the multiple reinforcing projections 15 corresponds to the pitch of the horn portions 8. The diameter of an imaginary circle circumscribing the multiple reinforcing projections 15 coincides with the outer diameter of the reinforcing ring 14.

[0052] The reinforcing piece 15 consists of a solid plate portion extending solidly from the bent portion 17 of the reinforcing ring 14 to one side in the axial direction. The reinforcing piece 15 (solid plate portion) extends to one and the other circumferential sides of the horn 8. The one and the other circumferential sides of the horn 8 are bounded by an imaginary plane that bisects the horn 8 in the circumferential direction and includes the central axis.

[0053] The end of one circumferential side of the reinforcing piece 15 is located close to the nearest pocket 11 on that circumferential side of the horn 8 (i.e., close to the pocket 11 with respect to an imaginary plane that further bisects the area between the aforementioned boundary and the nearest pocket 11 in the circumferential direction and includes the central axis). Similarly, the end of the other circumferential side of the reinforcing piece 15 is located close to the nearest pocket 11 on the other circumferential side of the horn 8.

[0054] The circumferential width of the reinforcing projection 15 is set constant over the entire length of the reinforcing projection 15 .

[0055] The entire reinforcing ring 14 is embedded in the synthetic resin 9 that forms the annular portion 7, and has no portion exposed from the synthetic resin 9. Therefore, the entire base portion 16 is embedded in the synthetic resin 9. The entire surface of the annular portion 7 consists of the inner diameter surface, the outer diameter surface, the side surface on the other axial direction, and the pocket bottom that defines the portion of the pocket 11 furthest on the other axial direction, and is formed of the synthetic resin 9.

[0056] The solid base 12 of the horn portion 8 is made of synthetic resin 9 and a reinforcing projection 15. Each of the claws 13a, 13b is formed only from the synthetic resin 9. The synthetic resin 9 covers the reinforcing projection 15 (solid plate portion) on both radial sides (inner and outer sides) and on both circumferential sides (one side and the other side).

[0057] The reinforcing projection 15 has an exposed end 18 that is exposed from the synthetic resin 9 towards one axial side. The exposed end 18 is located at one axial end of the solid base 12, and is a component of the side surface on one axial side of the cage 1. The entire remainder of the reinforcing projection 15, excluding the exposed end 18, is embedded in the synthetic resin 9.

[0058] The synthetic resin 9 may be any resin that can be injection molded, such as engineering plastics, and may be at least one of thermoplastic resin and thermosetting resin, and may be either crystalline resin or non-crystalline resin. The synthetic resin may be a resin that contains a thermosetting resin or a thermoplastic resin as a main component, and may contain other thermosetting resins, thermoplastic resins, rubber, glass fiber (GF), carbon fiber, carbon black, graphite, etc. as appropriate.

[0059] There is no adhesive layer between the metal material 10 and the synthetic resin 9. In insert molding, since almost the entire metal material 10 is embedded in the synthetic resin 9, the metal material 10 and the synthetic resin 9 can be strongly integrated without bonding the synthetic resin 9 and the metal material 10 with an adhesive. Therefore, the process of applying an adhesive to the metal material 10 before inserting the metal material 10 into a mold (not shown) can be omitted. When inserting the metal material 10 into the mold, the metal material 10 can be arranged so that the central axis of the metal material 10 faces the axial direction by contacting the exposed end 18 with the mold at three or more locations equally spaced in the circumferential direction. In addition, as a means for preventing the metal material 10 from moving improperly due to the flow of the synthetic resin 9 injected into the mold, for example, a means for magnetically attracting the exposed end 18 to the mold by installing an electromagnet in the mold can be adopted.

[0060] The deformation of the cage 1 caused by centrifugal force at a predetermined bearing rotation speed was calculated by CAE analysis for the cage 1 in which the synthetic resin 9 was formed using polyamide 66 (PA66) + GF and the metal material 10 was formed using SPCC equivalent to 5% of the rolling elements 4. In addition, a comparative example in which the metal material 10 was omitted from the cage 1 and the portion was replaced with the polyamide 66 (PA66) + GF was also calculated by numerical analysis. The predetermined bearing rotation speed was 5000 to 10000 rpm, and calculations were performed for every 1000 rpm (6 conditions). In the ball bearing used as the base model for the CAE analysis, considering the value of dmn (pitch circle diameter of the rolling elements 4 × bearing rotation speed per minute), a bearing rotation speed of 5000 rpm corresponds to a dmn value of 240,000, and a bearing rotation speed of 10000 rpm corresponds to a dmn value of 540,000.

[0061] In an analysis example of the cage 1, the state of deformation at 10,000 rpm is shown in Fig. 5, and in a comparative example, the state of deformation at 10,000 rpm is shown in Fig. 6. In Fig. 5 and Fig. 6, the solid line shows the shape of the cage at 10,000 rpm, and the chain line shows the shape of the cage when the bearing is stopped. Points A and A' shown in Fig. 5 and Fig. 6 are the corners where the tips of the claws 13b and 13b' of the horns 8 and 8' intersect with the inner diameter surface.

[0062] In the analysis example of the cage 1, the amount of displacement that is the difference between the radial position of point A when the bearing is stopped and the radial position of point A when the bearing is rotating at a predetermined speed is denoted as δ. In the comparative example, the amount of displacement that is the difference between the radial position of point A' when the bearing is stopped and the radial position of point A' when the bearing is rotating at a predetermined speed is denoted as δ'.

[0063] In the analysis results of the analytical example and the comparative example of the retainer 1, it was confirmed that the displacement δ of the analytical example of the retainer 1 was smaller than the displacement δ' of the comparative example under any speed condition from 5000 to 10000 rpm. In particular, at 10000 rpm, the displacement δ of the analytical example of the retainer 1 was 29% smaller than the displacement δ' of the comparative example. From these analysis results, it was confirmed that the metal material 10 of the retainer 1 shown in Figs. 1 to 4 has a reinforcing effect against centrifugal force.

[0064] As described above, the retainer 1 comprises a solid plate portion in which the reinforcing projection 15 extends solidly from the reinforcing ring 14 to one side in the axial direction, the reinforcing projection (solid plate portion) 15 extends to one and the other circumferential sides of the horn 8, and the synthetic resin 9 covers the reinforcing projection 15 from both radial and circumferential sides. As a result, the circumscribed circle diameter of the reinforcing projection 15 can be made smaller than the circumscribed circle diameter of the horn 8 compared to when the reinforcing projection 15 is the outer diameter surface of the horn 8. Also, compared to when a through hole is formed in the reinforcing projection 15 to integrally bond it to the synthetic resin 9, the reinforcing projection 15 and the synthetic resin 9 can be strongly integrated without using adhesive, and the reinforcing projection 15 can be made wider in the circumferential direction of the solid portion extending axially in a continuous manner from the reinforcing ring 14, thereby efficiently reinforcing the horn 8, thereby making the reinforcement by the metal material 10 more efficient.

[0065] In addition, the retainer 1 has a base plate portion 16 in which the reinforcing ring 14 is solidly connected around the entire circumference and extends radially, the base plate portion 16 extends around the entire circumference to the inner and outer diameter sides of the annular portion 7, and the entire base plate portion 16 is embedded in synthetic resin 9. Therefore, compared to the case in which a through hole is formed in the reinforcing ring 14 to integrally bond it to the synthetic resin 9, it is possible to achieve a strong integration between the reinforcing ring 14 and the synthetic resin 9 without using adhesive, and the solid portion of the reinforcing ring 14 that extends continuously around the entire circumference can be made wider in the radial direction to efficiently reinforce the annular portion 7. This makes reinforcement by the metal material 10 more efficient, and in the circumferential region where the horn portion 8 and the annular portion 7 are present, the reinforcing projection 15 and the reinforcing ring 14 form an L-shaped cross-sectional portion with no through hole, thereby enabling particularly efficient reinforcement.

[0066] In addition, the retainer 1 has exposed ends 18 of the reinforcing protrusions 15 exposed from the synthetic resin 9 towards one axial side, and the entire remainder of the reinforcing protrusions 15 except for the exposed ends 18 are embedded in the synthetic resin 9. As a result, insert molding can be performed in which the exposed ends 18 of the multiple reinforcing protrusions 15 are utilized for positioning the metal material 10 in a mold, and most of the metal material 10 can be covered with the synthetic resin 9 to integrate the metal material 10 and the synthetic resin 9.

[0067] Furthermore, since the metal material 10 of the cage 1 is formed from a cold-rolled steel plate, the reinforcing rings 14 and the reinforcing projections 15 can be easily formed by metal press working.

[0068] Furthermore, since the thickness of the metal material 10 of the cage 1 is 4% to 6% of the diameter of the rolling elements 4, the reinforcing effect of the metal material 10 can be obtained while avoiding an excessively thick plate.

[0069] Furthermore, the ball bearing according to the first embodiment has excellent resistance to deformation of the cage 1 due to centrifugal force, making it suitable for high-speed rotation.

[0070] In this way, the cage 1 is made of a metal plate having higher rigidity than the synthetic resin 9, and includes the reinforcing ring 14 having a wide solid portion formed without through holes as described above, and the metal material 10 reinforcing the annular portion 7 and the horn portion 8 with a plurality of reinforcing protrusions 15, so that the rigidity of the cage 1, particularly the ring rigidity and torsional rigidity of the horn portion 8, can be improved. As a result, even when the ball bearing is operated at high speed in a high-temperature environment, deformation of the cage 1 due to centrifugal force or heat, and vibration deformation of the cage 1 due to disturbances can be suppressed, and damage to the cage 1 caused by the claws 13a, 13b of the horn portion 8 interfering with the inner peripheral surface of the outer ring 3 can be prevented, and the performance of the ball bearing and, in turn, the performance of the rotating machine can be maintained well. In addition, in the unlikely event that a crack or the like occurs in the cage 1, the inserted metal material 10 can maintain the cage shape and retard the crack growth.

[0071] A second embodiment of the present invention will be described with reference to Figures 7 to 11. Note that, below, only the differences from the first embodiment will be described.

[0072] As shown in Figs. 7 and 8, in the metal material 20 according to the second embodiment, the shapes of the reinforcing ring 21 and the reinforcing projection 22 are changed from those in the first embodiment.

[0073] The reinforcing ring 21 has a flange portion 24 extending in the axial direction from the base portion 23. The flange portion 24 is formed by bending the outer periphery side of the base portion 23 toward the other side in the axial direction.

[0074] The reinforcing piece 22 comprises a solid plate portion 25 that is continuous with the inner periphery of the base portion 23 of the reinforcing ring 21, and a pair of rib portions 26, 26 that are continuous with both sides of the solid plate portion 25 in the circumferential direction.

[0075] The rib portion 26 is provided discontinuously with the reinforcing ring 21, and is bent from the solid plate portion 25 to extend in the radial direction. The rib portion 26 faces the base plate portion 23 of the reinforcing ring 21 in the axial direction. When the reinforcing projection 22 is deformed radially outward by centrifugal force, the rib portion 26 abuts against the base plate portion 23 in the axial direction. This abutment makes it possible to resist the centrifugal force acting on the reinforcing projection 22. The abutment portion between the rib portion 26 and the base plate portion 23 is formed on the outer diameter side of the base plate portion 23 to improve resistance.

[0076] The rib portion 26 is shaped so that it becomes shorter in the radial direction from the portion where it abuts against the base plate portion 23 toward one side in the axial direction.

[0077] The outer diameter of the reinforcing ring 21 is constant around the entire circumference. The outer diameter of the metal material 20 corresponds to the outer diameter of the reinforcing ring 21. The inner diameter of the reinforcing ring 21 corresponds to the diameter of an imaginary circle inscribed in the bent portion connected to the reinforcing piece 22.

[0078] The reinforcing protrusion 22 is formed thinner than the thickness of the base plate portion 23 of the reinforcing ring 21. This difference in thickness is satisfied between the reinforcing protrusion 22 and the base plate portion 23 as a whole. The base plate portion 23 is the main portion that exerts torsional rigidity, and does not affect the mass of the horn portion 8, so it is preferable to make it thicker than the reinforcing protrusion 22. The reinforcing protrusion 22 affects the mass of the horn portion 8, so it is preferable to make it as thin as possible. The thickness of the auxiliary flange portion 24 does not need to be as thick as the base plate portion 23, and is equal to or less than the thickness of the solid plate portion 25. Similarly, the auxiliary rib portion 26 does not need to be as thick as the base plate portion 23 or the solid plate portion 25, and is made thinner than the thickness of the solid plate portion 25.

[0079] The flange portion 24 has an exposed end portion 27 that is exposed toward the other axial side from the synthetic resin 9. The exposed end portion 27 is made up of a tip surface of the flange portion 24 on the other axial side that is continuous around the entire circumference.

[0080] The total axial length of the reinforcing piece 22 is shorter than that of the first embodiment because the reinforcing effect is enhanced by the high rigidity of the pair of ribs 26, 26, thereby suppressing the centrifugal force acting on the reinforcing piece 22. The total axial length of the reinforcing piece 22 is greater than or equal to ¼ and less than or equal to half of the total axial length of the horn portion 8.

[0081] The entire reinforcing protrusion 22 is embedded in the synthetic resin 9. The entire remaining portion of the reinforcing ring 21, excluding the exposed end 27, is embedded in the synthetic resin 9. During insert molding, since almost the entire metal material 20 is embedded in the synthetic resin 9, it is possible to strongly integrate the metal material 20 and the synthetic resin 9 without bonding the metal material 20 with an adhesive. When inserting the metal material 20 into the mold, the exposed end portion that is continuous around the entire circumference of the metal material 20 is brought into contact with the mold at three or more locations that are evenly spaced in the circumferential direction, so that the central axis of the metal material 20 can be oriented in the axial direction.

[0082] A method for manufacturing the reinforcing pieces of the metal material 20 is shown generally in FIG. 9(a) to FIG. 11(b).

[0083] First, the workpiece W shown in Fig. 9(a) and (b) is a flat blank plate punched out from a cold-rolled steel plate. The workpiece W is composed of an annular plate portion W1 as a reinforcing ring, and a plurality of bent pieces W2 protruding from the inner diameter side plate edge of the annular plate portion W1 at equal intervals in the circumferential direction toward the inner diameter side. The bent pieces W2 are composed of a rectangular plate portion W3 as a solid plate portion, and a pair of approximately triangular plate portions W4 as a pair of ribs. The approximately triangular plate portions W4 and the annular plate portion W1 are cut out when punched out from the cold-rolled steel plate, and a small clearance C is formed between the approximately triangular plate portions W4 and the annular plate portion W1. The bent pieces W2 are made thinner than the annular plate portion W1 by pressing when punched out from the cold-rolled steel plate, and in particular, the approximately triangular plate portion W4 is made thinner.

[0084] Next, the pair of approximately triangular plate portions W4 are bent by 90 degrees relative to the rectangular plate portion W3 by metal press processing, so as to stand in a state aligned in the axial and radial directions as shown in Figs. 10(a) and 10(b).

[0085] Next, the rectangular plate portion W3 of the workpiece W is bent 90° relative to the annular plate portion W1 by metal pressing to extend in the axial direction as shown in Figures 11(a) and 11(b). This completes the reinforcing protrusion 22 consisting of the solid plate portion 25 and the pair of rib portions 26, 26, and the pair of rib portions 26, 26 are arranged so as to contact or face each other in the axial direction with a slight clearance on one side surface of the annular plate portion W1 on the axial direction and butt against each other when deformed by centrifugal force.

[0086] 7 and 8 is formed by metal pressing to bend the outer periphery of the annular plate portion W1 by 90°, completing the reinforcing ring 21. The flange portion 24 may be formed when punching out from a cold-rolled steel plate.

[0087] In the retainer of the second embodiment, the reinforcing protrusions 22 are continuous with the inner circumference of the reinforcing ring 21, so that the reinforcing protrusions 22 can be positioned further toward the inner diameter side compared to the first embodiment, thereby reducing the centrifugal force acting on the solid plate portion 25.

[0088] In addition, the retainer of the second embodiment has a reinforcing protrusion 22 that is discontinuously arranged with the reinforcing ring 21 and a rib portion 26 that is bent from the solid plate portion 25 so as to axially abut against a side surface on one axial side of the reinforcing ring 21.As a result, the rib portion 26 and the side surface on one axial side of the reinforcing ring 21 abut against each other to resist centrifugal force, thereby making it possible to increase the bending rigidity of the reinforcing protrusion 22 against centrifugal force.Furthermore, the rib portion 26 can be bent to make it larger, thereby making the bending rigidity of the reinforcing protrusion 22 against centrifugal force even greater.

[0089] Furthermore, in the cage according to the second embodiment, the rib portions 26 are formed on both circumferential sides of the reinforcing projection 22, and therefore the rib portions 26 butt against the reinforcing ring 21 on both circumferential sides of the reinforcing projection 22, thereby further increasing the bending rigidity of the reinforcing projection 22 against centrifugal force. Note that, although the rib portions may be formed on only one of the circumferential sides of the reinforcing projection 22 (not shown), forming the rib portions 26 on both circumferential sides of the reinforcing projection 22 as in the second embodiment provides superior bending rigidity of the reinforcing projection 22.

[0090] Furthermore, in the retainer of the second embodiment, the reinforcing protrusion 22 is formed thinner than the thickness of the base portion 23 of the reinforcing ring 21, thereby making it possible to thin the reinforcing protrusion 22 whose rigidity is increased by the formation of the rib portion 26, thereby reducing the mass of the reinforcing protrusion 22 and thereby suppressing the centrifugal force acting on the reinforcing protrusion 22.

[0091] Furthermore, in the retainer of the second embodiment, the rib portion 26 has a shape that becomes shorter radially toward one side in the axial direction, so that the mass of the rib portion 26 can be reduced at the tip side of the reinforcing piece 22 without reducing the abutment area between the rib portion 26 and the reinforcing ring 21, thereby further reducing the centrifugal force acting on the reinforcing piece 22.

[0092] Furthermore, in the cage according to the second embodiment, the reinforcing ring 21 has the flange portion 24 extending in the axial direction, and thus the flange portion 24 can further increase the rigidity of the reinforcing ring 21.

[0093] Furthermore, in the retainer of the second embodiment, flange portion 24 extends toward the other axial side so as to have an exposed end 27 that is exposed from synthetic resin 9 toward the other axial side, and the entire remainder of reinforcing ring 21 except for exposed end 27 is embedded in synthetic resin 9. As a result, insert molding can be performed in which the exposed end 27 of flange portion 24 is utilized for positioning metal material 20 in a mold, and most of the metal material 20 can be covered with synthetic resin 9 to integrate the metal material 20 and the synthetic resin 9.

[0094] In the second embodiment, CAE analysis revealed that by changing the position of the reinforcing protrusion 22 to the inner diameter side as described above, thinning the reinforcing protrusion 22, adopting the rib portion 26, and adopting the flange portion 24, the rigidity of the retainer can be improved by nearly 170% compared to the first embodiment.

[0095] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Therefore, the scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0096] 1 Cage 2. Inner Circle 3 Outer ring 4 Rolling elements 7 Annular section 8 parts 9. Synthetic Resins 10, 20 Metal materials 11 Pocket 12 Solid Base 13a, 13b Claws 14, 21 Reinforcement ring 15, 22 Reinforcement protrusions 16, 23 Circuit board section 18, 27 Exposed end 24 Flange 25 Solid plate 26 Rib section

Claims

1. A cage comprising an annular portion and a plurality of horns protruding from the annular portion at equal intervals in the circumferential direction to one side in the axial direction, wherein spaces between adjacent horns in the circumferential direction form pockets for accommodating rolling elements, the annular portion and the plurality of horns being formed by insert molding that integrates a synthetic resin with a metal material, the metal material integrally having a reinforcing ring continuing around the entire circumference and a plurality of reinforcing projections protruding from the reinforcing ring to one side in the axial direction, the reinforcing ring being disposed on the annular portion, and the plurality of reinforcing projections being respectively disposed on the horns, the reinforcing piece has a solid plate portion extending solidly from the reinforcing ring toward one side in the axial direction, the solid plate portion extending to one side and the other side in the circumferential direction of the horn, The synthetic resin covers the solid plate portion from both radial and circumferential sides, The reinforcing piece is continuous with the inner periphery of the reinforcing ring, A retainer characterized in that the reinforcing projection is discontinuous with the reinforcing ring and has a rib portion bent from the solid plate portion so as to axially abut against a side surface on one axial side of the reinforcing ring.

2. the reinforcing ring has a base plate portion which is continuous and solid around the entire circumference and extends in a radial direction, the base plate portion extending around the entire circumference to the inner diameter side and the outer diameter side of the annular portion, 2. The cage according to claim 1, wherein the base plate portion is entirely embedded in the synthetic resin.

3. 3. The cage according to claim 1, wherein the rib portion is formed on one or both sides in the circumferential direction of the reinforcing projection.

4. 4. The cage according to claim 1, wherein the reinforcing projection is formed to be thinner than a thickness of the base plate portion of the reinforcing ring.

5. The cage according to claim 1 , wherein the rib portion is shaped so as to become shorter in the radial direction toward one axial side.

6. The cage according to claim 1 , wherein the reinforcing ring has a flange portion extending in the axial direction.

7. A retainer comprising an annular portion and a plurality of horns protruding from the annular portion at equal intervals in the circumferential direction to one side in the axial direction, wherein the spaces between adjacent horns in the circumferential direction form pockets for accommodating rolling elements, wherein the annular portion and the plurality of horns are formed by insert molding which integrates a synthetic resin with a metal material, wherein the metal material integrally has a reinforcing ring continuing around the entire circumference and a plurality of reinforcing protrusions protruding from the reinforcing ring to one side in the axial direction, wherein the reinforcing ring is disposed on the annular portion, and the plurality of reinforcing protrusions are each disposed on one of the horns, the reinforcing piece has a solid plate portion extending solidly from the reinforcing ring toward one side in the axial direction, the solid plate portion extending to one side and the other side in the circumferential direction of the horn, The synthetic resin covers the solid plate portion from both radial and circumferential sides, The retainer according to claim 1, wherein the reinforcing ring has a flange portion extending in the axial direction.

8. A retainer as described in claim 6 or 7, wherein the flange portion extends to the other axial side so as to have an exposed end portion exposed from the synthetic resin toward the other axial side, and the entire remainder of the reinforcing ring excluding the exposed end portion is embedded in the synthetic resin.

9. A retainer described in any one of claims 1 to 8, wherein the reinforcing protrusion has an exposed end exposed from the synthetic resin toward one axial side, and the entire remainder of the reinforcing protrusion excluding the exposed end is embedded in the synthetic resin.

10. The cage according to claim 1 , wherein the metal material is made of a cold-rolled steel plate.

11. 11. The cage according to claim 10, wherein the thickness of the metal material is 4% to 6% of the diameter of the rolling elements.

12. 12. The cage according to claim 1, wherein the synthetic resin is at least one of a thermosetting resin and a thermoplastic resin.

13. A ball bearing comprising: the cage according to claim 1 ; an inner ring; an outer ring; and a plurality of the rolling elements disposed between the inner ring and the outer ring.

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