JP2009197899A - Double-row angular bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-row angular bearing having an improved rolling life and reduced costs. <P>SOLUTION: The double-row angular bearing comprises inner rings 24A, 24B having inside rolling surfaces 28, 29 on the outer diameter faces, respectively, an outer ring 25 having outside rolling surfaces 26, 27 on the inner diameter face, and rolling elements 30 rollingly stored between each of the outside rolling surfaces 26, 27 of the outer ring 25 and each of the inside rolling surfaces 28, 29 of the inner rings 24A, 24B. At least one of the outer ring 25 and the inner ring 24 is molded into a plastic product with cold rolling using martensitic stainless steel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a double-row angular bearing, and more particularly to a double-row angular bearing that is optimal for a wheel bearing device for rotatably supporting a wheel with respect to a vehicle body in a vehicle such as an automobile.

  As shown in FIG. 12, in a double row angular bearing used for a wheel bearing device of an automobile, a bearing 100 includes an outer ring 105 having double row outer raceway surfaces 120 and 121 formed on the inner circumference, and an outer circumference on the outer circumference 105. A pair of inner races 108, 109 formed with inner race surfaces 118, 119 opposite to the outer race surface, outer race surfaces 120, 121 of the outer race 105, and inner race surfaces 118, 119 of the inner races 108, 109, And the double row rolling elements 122 accommodated so as to roll freely.

  The axial opening between the outer ring 105 and the inner rings 108 and 109 is closed by seal members S and S. For this reason, seal mounting grooves 110 and 111 are provided at the axially open ends of the inner diameter surface of the outer ring 105.

  The inner rings 108 and 109 include a large diameter portion 112 and a small diameter portion 113, and a rolling surface 118 (119) is formed on the outer diameter surface of the continuous portion 114 between the large diameter portion 112 and the small diameter portion 113. .

  As shown in FIG. 13, the outer ring 105 is generally formed by cutting a short cylindrical material 150 in a range indicated by cross hatching. As for this raw material 150, as shown to Fig.14 (a), the fiber flow F is extended in the axial direction. For this reason, also in the molded outer ring 105, as shown in FIG. 14B, the fiber flow F extends in the axial direction. The fiber flow refers to the flow of the material structure, and is also referred to as a fibrous metal structure.

  Further, as shown in FIG. 15, the inner ring 108 (109) is also formed by shaving a short cylindrical material 151 in a range indicated by cross hatching. At this time, in the material 151, as shown in FIG. 16, the fiber flow F extends in the axial direction. Therefore, the fiber flow F extends in the axial direction also in the molded inner ring 108 (109).

  In a double row angular bearing used for a bearing device for an automobile wheel or the like, corrosion resistance is required. For this reason, stainless steel (JIS SUS440C) or the like is used for the outer ring or inner ring of the bearing. SUS440C (martensitic stainless steel) is a corrosion-resistant bearing steel that can secure a predetermined corrosion resistance while achieving a hardness of 55 HRC or higher, which is a necessary hardness for bearing steel, by performing quenching and tempering.

  However, the level of corrosion resistance required for corrosion resistant bearings is further increased with the recent expansion of applications of corrosion resistant bearings. Examples of the steel having excellent corrosion resistance include austenitic stainless steel such as JIS SUS304. Since SUS304 has corrosion resistance exceeding SUS440C, it is superior to SUS440C from the viewpoint of corrosion resistance.

Therefore, there are those using austenitic stainless steel for the inner ring and outer ring of the bearing (Patent Document 1 and Patent Document 2).
JP 2001-330038 A JP 2002-147467 A

  However, the SUS material contains more rare metals such as Cr than steel materials such as SUJ2 that are generally used for bearings, and the unit price is high and the cost is high. Moreover, in the molding method as shown in FIG. 13, it is necessary to mold a rolling surface, a seal mounting groove or the like on the inner diameter surface as the shape of the outer ring, and a large amount of material is removed (material loss = input weight-product weight). Therefore, the material cost increases accordingly. Also in the inner ring, the weight to be removed is increased, and the material cost is increased accordingly.

  Further, in the cutting process as shown in FIG. 14 or FIG. 16, the fiber flow is divided at the rolling surface. For this reason, cracks and peeling are likely to occur on the rolling surface, and the lifetime is relatively short.

  In view of the above problems, the present invention provides a double-row angular bearing capable of improving the rolling life and achieving a reduction in cost.

  The double-row angular bearing according to the present invention includes an inner ring having a rolling surface on the outer diameter surface, an outer ring having a rolling surface on the inner diameter surface, and an outer rolling surface of the outer ring and an inner rolling surface of the inner ring. A double-row angular bearing with a rolling element accommodated in a freely movable manner, wherein at least one of an outer ring and an inner ring is a plastic work product formed by cold rolling using martensitic stainless steel It is. Here, cold rolling (cold rolling) is a processing method in which a material (blank) is rolled while being kept cold (normal temperature) without applying heat. In other words, two blanks (inner diameter and outer diameter) that are designed to have the inner and outer diameters smaller than the workpiece (finished product after machining) and basically the inner and outer diameter straight blanks (materials) to be machined. It is a processing method that forms a workpiece by rolling (rolling) while rotating it.

  Since the double-row angular bearing of the present invention is a plastic processed product in which at least one of the outer ring and the inner ring is formed by cold rolling, the yield of the plastic processed product can be improved. In other words, unlike rolling that cuts off an unnecessary portion of a material, cold rolling can be performed by expanding a material that is thinner than the outer diameter of the product, and waste of material does not occur. In addition, productivity is higher than cutting because the machining time is short and the tool has a long life. Furthermore, although the tools (molding roll, mandrel) to be used need to be replaced according to the processed product, stable processing accuracy can be obtained. Furthermore, unlike the cutting process, since the fiber flow is not cut, the occurrence of cracks and peeling on the rolling surface can be suppressed, and the product can have a long life.

  Moreover, since the double row angular bearing of the present invention is a plastic processed product using martensitic stainless steel, it becomes high strength and high hardness by quenching and tempering.

  The inclination of the fiber flow on the rolling surface of the plastic workpiece is preferably 15 ° or less with respect to the tangential direction of the rolling surface except for the shoulder portion of the rolling surface or the vicinity thereof. If the inclination of the fiber flow is such, the fiber flow flows in a shape close to the rolling surface shape. The slope of the fiber flow is connected by a straight line from the center of curvature of the rolling surface to the point where the cross section of the fiber flow is deposited, and an orthogonal line between the straight line and the straight line at the intersection of the point, and the point The angle formed by the tangent of the fiber flow at.

  Plastic processed product: C: 0.90 to 1.20% by weight, Si: 1.0% by weight or less, Mn: 1.0% by weight or less, P: 0.040% by weight or less, S: 0.030% by weight %, Ni: 0.75% by weight or less, Cr: 16.0 to 18.0% by weight, Mo: 0.75% by weight or less, martensitic stainless steel containing a blank formed by spheroidizing annealing and plastic working The inclination of the fiber flow on the rolling surface of the product is 15 ° or less with respect to the tangential direction of the rolling surface except for the shoulder portion of the rolling surface or the vicinity thereof, and at least the hardness of the surface of the rolling surface is at least It is preferable to be 55 to 64 HRC by quenching and tempering.

  Plastic processed products are: C: 0.50 to 0.75 wt%, Si: 0.5 wt% or less, Mn: 1.0 wt% or less, P: 0.030 wt% or less, S: 0.030 wt% %, Ni: 0.60 wt% or less, Cr: 11.5 to 13.5 wt%, Mo: 0.50 wt% or less, martensitic stainless steel containing spheroidizing annealed blank, plastic working The inclination of the fiber flow on the rolling surface of the product is 15 ° or less with respect to the tangential direction of the rolling surface except for the shoulder portion of the rolling surface or the vicinity thereof, and at least the hardness of the surface of the rolling surface is at least It is preferable to be 55 to 64 HRC by quenching and tempering.

  Here, the spheroidizing annealing is a heat treatment in which carbides in steel are made spherical and uniformly dispersed. For this reason, by performing spheroidizing annealing, plastic processing and machining can be facilitated, or the mechanical properties can be improved. The carbide in the plastic processed product is preferably (a + b) / 2 ≦ 50 μm, particularly (a + b) / 2 ≦ 30 μm, where a is the major axis length and b is the minor axis length. Is preferred.

  If the plastic workpiece is an outer ring, a circumferential groove (annular recess) is provided in the axially central portion of the outer diameter surface. This is because by making the shape after plastic working a substantially uniform thickness, the blank can be rolled almost uniformly during plastic working by cold rolling, so that plastic working can be facilitated.

  In the wheel bearing device of the present invention, since the outer ring and the inner ring are formed by cold rolling, the product yield and productivity can be improved, and cost reduction can be achieved. In addition, the outer ring and the inner ring can obtain stable machining accuracy and a long life, and can improve the quality of the bearing. Further, the weight of the outer ring and the inner ring can be reduced, and the fuel efficiency of the automobile can be reduced. As described above, since the cylindrical material is not cut out and molded, the amount of material removed in the cutting process is reduced, the waste of the material is reduced, and the cost can be reduced.

  Since the plastic processed product is martensitic stainless steel, it becomes high strength and high hardness by quenching and tempering. For this reason, a high quality product can be provided. Moreover, although the corrosion resistance of martensitic stainless steel is generally inferior to that of other types of stainless steel, it is superior to SUJ2 in corrosion resistance and can sufficiently cope with the corrosion resistance required for automobile wheel bearing devices and the like.

  By setting the inclination of the fiber flow on the rolling surface of the plastic work product to be 15 ° or less with respect to the tangential direction of the rolling surface, the fiber flow flows in a shape close to the shape of the rolling surface. . Thereby, generation | occurrence | production of the crack, peeling, etc. in a rolling surface can be suppressed, and lifetime improvement as a product can be achieved.

  C: 0.90 to 1.20 wt%, Si: 1.0 wt% or less, Mn: 1.0 wt% or less, P: 0.040 wt% or less, S: 0.030 wt% or less, Ni: Blank formed by spheroidizing martensitic stainless steel containing 0.75 wt% or less, Cr: 16.0 to 18.0 wt%, Mo: 0.75 wt% or less, or C: 0.50 to 0 .75 wt%, Si: 0.5 wt% or less, Mn: 1.0 wt% or less, P: 0.030 wt% or less, S: 0.030 wt% or less, Ni: 0.60 wt% or less, When a blank obtained by spheroidizing martensitic stainless steel containing Cr: 11.5 to 13.5% by weight and Mo: 0.50% by weight or less is used, by performing spheroidizing annealing, plastic working or machine Processing can be facilitated or mechanical properties can be improved. For this reason, the productivity of this bearing can be further improved, and the rolling element can be stably rolled over a long period of time by setting the surface hardness of the rolling surface to 55 to 64 HRC by quenching and tempering. Can do.

  If the plastic work product is an outer ring, a circumferential groove (annular recess) is provided in the axial center of the outer diameter surface, which facilitates plastic working and reduces weight and cost. Can do. Further, the carbide in the plastic processed product is defined as (a + b) / 2 ≦ 50 μm when the major axis length is a and the minor axis length is b, thereby eliminating coarse carbides and reducing the size of the carbides. Can be reduced. For this reason, even if stress concentration occurs, generation of cracks can be suppressed, and noise during rolling can be reduced. Furthermore, it is possible to prevent a reduction in processing accuracy and perform high-quality processing. In particular, by setting (a + b) / 2 ≦ 30 μm, a higher quality product can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a double-row angular bearing according to the first embodiment. The bearing includes an outer ring 25 having double-row outer rolling surfaces 26 and 27 formed on the inner periphery, and an outer rolling surface 26 of the outer ring 25 on the outer periphery. 27 between a pair of inner races 24A, 24B formed with inner race surfaces 28, 29 opposite to 27, and outer race surfaces 26, 27 of outer race 25 and inner race surfaces 28, 29 of inner races 24A, 24B. A double row rolling element 30 accommodated in a freely rolling manner. The rolling element 30 is held by a cage 31 interposed between the outer ring 25 and the inner rings 24A and 24B. A seal member S is attached to both openings of the rolling bearing (openings between the outer ring 25 and the inner rings 24A and 24B).

  As shown in FIG. 2, the outer ring 25 is formed with an annular recess 51 in the axial center portion of the outer diameter surface 50, and correspondingly, a circumferential convex portion (bulging portion) in the axial center portion of the inner diameter surface 52. ) 53 is provided. Outer rolling surfaces 26 and 27 are formed on both sides of the circumferential protrusion 53, and seal mounting grooves 54 and 55 are formed on the outer sides of the outer rolling surfaces 26 and 27.

  One inner ring 24A and the other inner ring 24B can be formed of common parts. Since this bearing 2 is used for a wheel bearing device, one inner ring 24A is called an outboard side inner ring 24, and the other inner ring 24B is called an inboard side inner ring 24. The side closer to the outside of the vehicle in the state assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing). As shown in FIG. 1, the inner ring 24 (24 </ b> A, 24 </ b> B) is formed of a short cylindrical body having a thick portion 85 and a thin portion 86, and is transferred to an outer diameter surface between the thick portion 85 and the thin portion 86. A running surface 28 (29) is formed. The outer diameter surface of the thick portion 85 becomes the seal mounting surface 63.

  Next, a method for manufacturing the outer ring 25 of the rolling bearing will be described. In this outer ring manufacturing method, as shown in FIG. 3, a long pipe material P is cut into a predetermined size and turned to form a short material 34. Thereafter, a cold rolling process is performed on the material 34. Cold rolling (cold rolling) is a processing method in which a raw material (blank) is rolled while being kept cold (normal temperature) without applying heat. In other words, two blanks (inner diameter and outer diameter) that are designed to have the inner and outer diameters smaller than the workpiece (finished product after machining) and basically the inner and outer diameter straight blanks (materials) to be machined. It is a processing method that forms a workpiece by rolling (rolling) while rotating it.

  As the material 34, C: 0.90 to 1.20% by weight, Si: 1.0% by weight or less, Mn: 1.0% by weight or less, P: 0.040% by weight or less, S: 0.030% by weight % Or less, Ni: 0.75% by weight or less, Cr: 16.0 to 18.0% by weight, Mo: 0.75% by weight or less martensitic stainless steel A that has been subjected to spheroidizing annealing Can do. Here, the spheroidizing annealing is a heat treatment in which carbides in steel are made spherical and uniformly dispersed. For this reason, by performing spheroidizing annealing, plastic processing and machining can be facilitated, or the mechanical properties can be improved.

  In this case, the Si amount is set to 1.0% by weight or less in order to improve the cold rolling workability. The reason why the amount of C is set to 0.90 to 1.20% by weight is to ensure the hardness after quenching and tempering necessary for the outer ring of the bearing.

  Further, as the material 34, C: 0.50 to 0.75% by weight, Si: 0.5% by weight or less, Mn: 1.0% by weight or less, P: 0.030% by weight or less, S: 0.0. Martensitic stainless steel B containing 030 wt% or less, Ni: 0.60 wt% or less, Cr: 11.5 to 13.5 wt%, Mo: 0.50 wt% or less was spheroidized and annealed. May be.

  Also in this case, the reason why the Si amount is 0.5% by weight or less is to improve the cold rolling workability. The reason why the amount of C is set to 0.50 to 0.75% by weight is to ensure the hardness after quenching and tempering necessary for the outer ring of the bearing. In the case of martensitic stainless steel B, carbides are smaller than martensitic stainless steel A.

  In the cold rolling process, a cold rolling process is performed with a rolling apparatus as shown in FIG. The rolling device includes an inner diameter mandrel 47 and an outer diameter forming roll 48. An outer ring inner surface forming part 67 for forming the inner diameter surface of the outer ring 25 is formed on the outer peripheral surface of the mandrel 47, and an outer ring outer diameter surface forming part 68 for forming the outer diameter surface of the outer ring 25 on the outer diameter surface of the forming roll 48. Is formed.

  The outer ring inner diameter surface forming portion 67 includes rolling surface forming portions 67a and 67a and seal groove forming portions 67b and 67b. The outer ring outer diameter surface forming portion 68 includes an annular recess forming portion 68a and outer diameter surface forming portions 68b and 68b.

  In this case, the cylindrical material 34 shown in FIG. 5A is externally fitted to the mandrel 47, and the forming roll 48 is rotated about its axis while the material 34 is sandwiched between the mandrel 47 and the forming roll 48. Let As a result, the outer ring 25 can be formed.

By the way, the fiber flow F in the raw material 34 is a flow along the axial direction as shown in FIG. For this reason, the fiber flow F of the outer ring | wheel 25 shape | molded by cold rolling has a flow as shown in FIG.5 (b).

In this case, as shown in FIG. 6, the inclination of the fiber flow of the rolling surface of the plastic workpiece is the tangential direction of the rolling surface 26 (27) except for the shoulder portion of the rolling surface 26 (27) or the vicinity thereof. Is 15 ° or less. That is, the straight line L and the point P ₁ are connected by a straight line L from the center of curvature O of the rolling surface 26 (27) (see FIG. 5B) to the point P ₁ where the cross section of the fiber flow F is deposited. The angle α formed by the orthogonal line T with the straight line L at the intersection point and the tangent line T ₁ of the fiber flow F at the point P ₁ is 15 ° or less.

  Further, the carbide in the outer ring 25 which is a plastic processed product has (a + b) / 2 ≦ 50 μm, where the major axis length is a and the minor axis length is b. As shown in FIG. 7, the major axis length is the maximum length in the longitudinal direction, and the minor axis length is the maximum length in the lateral direction (direction perpendicular to the longitudinal direction).

  The material 34 may have a shape as shown in FIG. That is, the material 34 shown in FIG. 8 has an outer diameter surface 34 a that is a cylindrical surface, but an inner diameter surface 34 b that has a small diameter portion 37 at the center in the axial direction, and medium diameter portions 38 a provided on both sides of the small diameter portion 37. , 38b and large diameter portions 39a, 39b provided at axial end portions.

  If this material 34 is used, the medium diameter portions 38a, 38b constitute the rolling surfaces 26, 27, and the large diameter portions 39a, 39b constitute the seal mounting grooves 54, 55. For this reason, the deformation amount of each part can be reduced and workability can be improved. Further, the fiber flow F in the material 34 is a flow along the axial direction as shown in FIG. For this reason, the fiber flow F of the outer ring | wheel 25 shape | molded by cold rolling has a flow as shown in FIG.8 (b).

  Moreover, the 1st circumferential direction protruding part 35 is formed in the small diameter part 37, and the 2nd circumferential direction protruding part 36 is formed in the medium diameter parts 38a and 38b. And this 1st circumferential direction convex part 35 comprises the shoulder part 71 between the rolling surfaces 26 and 27, and the counter bore 72 (each rolling surface is formed in the 2nd circumferential direction convex part 35. 26 and 27, shoulder portions formed on the seal mounting grooves 54 and 55 side).

  Thus, if the blank 34 is provided with the circumferentially convex ridge 35 constituting the shoulder 71 between the rolling surfaces on the inner diameter surface, the satisfaction of the outer ring shoulder (track surface shoulder) is improved. The occurrence of microcracks can be suppressed. As a result, even when the bearing is tilted by the moment load from the tire when the vehicle is turning and the rolling element 30 passes near the shoulder 71, there is no microcrack, so the rolling life is not adversely affected. Moreover, due to the unsatisfactory of the shoulder portion 71, individual differences do not occur in the riding situation.

  When the step of the counter bore 72 enters the recess of the mandrel 47 (counter bore forming portions 75 and 75 (see FIG. 4)) at the start of rolling (rolling), the material 34 moves in the width direction of the space between the forming roll 48 and the mandrel 47. It can be located just in the center, and the initial rolling behavior is stable. Thereby, rolling will be made equal to right and left, and a satisfaction degree will also become equal right and left. That is, the place where a crack is likely to occur can be satisfied. Molded products are of high quality.

  Moreover, in order to eliminate the lack of satisfaction, the blank thickness is increased, the shoulder portion of the rolling surface is formed, and then the turning operation is not performed. Productivity can be improved and costs can be reduced.

  After the rolling process, the surface is hardened by quenching and tempering in a heating furnace or induction heating, and then the cutting process is performed. In this case, the seal mounting grooves 54 and 55 at the end portions in the axial direction, the rolling surfaces 26 and 27, the both end surfaces 56 and 57, and the outer diameter surface 50 are cut. For this reason, these cuttings can be called hardened steel cutting. In other words, hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it is called hardened steel cutting in order to clarify that the cutting is after heat treatment (after quenching and tempering). did. Since cutting is performed after quenching and tempering, the heat treatment deformation of the material can be removed in this cutting process. When quenching and tempering are performed, the residual tensile stress tends to remain, and the fatigue strength decreases as it is. For this reason, if the surface is cut, a compressive residual stress can be given to the outermost surface portion, thereby improving the fatigue strength. In this case, the hardness of at least the bottom surfaces of the rolling surfaces 26 and 27 is 55 to 64 HRC. After cutting, the seal mounting grooves 54 and 55, the rolling surfaces 26 and 27, and the outer diameter surface 50 are ground, and then assembled into a bearing. At the time of grinding, both end faces 56 and 57 may also be ground. In addition, the machining process is not a hardened steel cutting after the heat treatment but a turning in a raw material state after the rolling process. It may be a conventional process.

  In the double-row angular bearing of the present invention, the outer ring 25 is formed by cold rolling, so that the yield and productivity of the product can be improved and the cost can be reduced. In addition, the outer ring 25 can obtain stable machining accuracy and a long service life, and can improve the quality of the bearing. Further, the weight of the outer ring 25 can be reduced, and the fuel efficiency of the automobile can be reduced. As described above, since the cylindrical material is not cut out and molded, the amount of material removed in the cutting process is reduced, the waste of the material is reduced, and the cost can be reduced.

  Since the plastic processed product is martensitic stainless steel, it becomes high strength and high hardness by quenching and tempering. For this reason, a high quality product can be provided. Moreover, although the corrosion resistance of martensitic stainless steel is generally inferior to that of other types of stainless steel, it is superior to SUJ2 in corrosion resistance and can sufficiently cope with the corrosion resistance required for automobile wheel bearing devices and the like.

  By setting the inclination of the fiber flow F on the rolling surface of the plastic workpiece to be 15 ° or less with respect to the tangential direction of the rolling surfaces 26 and 27, the fiber flow F has a shape close to the shape of the rolling surface. Will flow in. Thereby, generation | occurrence | production of the crack, peeling, etc. in the rolling surfaces 26 and 27 can be suppressed, and lifetime improvement as a product can be achieved.

  When a blank obtained by spheroidizing martensitic stainless steel is used, plastic working and machining can be facilitated or mechanical properties can be improved by performing spheroidizing annealing. For this reason, the productivity of this bearing can be further improved, and the rolling element can be stably rolled over a long period of time by setting the surface hardness of the rolling surface to 55 to 64 HRC by quenching and tempering. Can do.

  By the way, if there is a large carbide (eutectic carbide), if stress concentrates there, cracks are not easily generated. When the major axis length is a and the minor axis length is b, by defining (a + b) / 2 ≦ 50 μm, the size of the carbide can be reduced. For this reason, even if stress concentration occurs, generation of cracks can be suppressed, and noise during rolling can be reduced. Furthermore, it is possible to prevent a reduction in processing accuracy and perform high-quality processing. In particular, by setting (a + b) / 2 ≦ 30 μm, a higher quality product can be provided.

  Next, FIG. 9 shows a second embodiment. In this case, the inner rings 24A and 24B are also formed by cold rolling. The inner ring 24 (24A, 24B) includes a large diameter portion 60, a small diameter portion 61, and a tapered portion 62 between the large diameter portion 60 and the small diameter portion 61. In this case, the outer diameter surface of the large diameter portion 60 becomes the seal mounting surface 63, and the outer diameter surface of the tapered portion 62 becomes the inner rolling surface 28 (29).

  Similarly to the outer ring 25, the inner ring 24 is formed by cold rolling of a raw material of the inner ring that is substantially the shape of the inner ring 24. This material is quenched and tempered in a heating furnace, induction heating, or the like to harden the surface and then cut. That is, hardened steel cutting is performed. In this case, the inner diameter surface, both end surfaces 65 and 66, the seal mounting surface 63, and the inner rolling surface 28 (29) are hardened steel cut. The cutting process may be a conventional process in which turning is performed in a raw material state after the rolling process, instead of the quenching steel cutting after the heat treatment.

  Further, as the material of the inner ring 24, a material obtained by spheroidizing annealing of the same martensitic stainless steel as the material of the outer ring 25 is used. Further, at least the rolling surface 28 (29) has a hardness of 55 to 64 HRC.

  For this reason, in the bearing shown in FIG. 9, in addition to the outer ring 25, the inner rings 24A and 24B are also plastic processed products formed by cold rolling using martensitic stainless steel. The same effect as the effect which the outer ring 25 has is produced. For this reason, an extremely high quality bearing can be provided at a low price.

  Further, in the molding method, one inner ring is taken out as a material, but a pair of inner rings may be taken out with one material. That is, a cylindrical material 70 as shown in FIG. 10 from which a pair of inner rings can be taken out is formed, and as shown in FIG. 11A, the inner ring constituting material 73 (a pair of inner rings are integrated by cold rolling). Of connected shapes). That is, the inner ring constituent material 73 includes a cylindrical main body 74 in the center in the axial direction, and large end portions 76a and 76b that are connected to both ends of the main body 74 via tapered portions 75a and 75b. It is comprised from the cylindrical body which has.

  The inner ring constituent material 73 configured in this way is cut at the center in the axial direction to form a pair of inner rings 24 (24A) and 24 (24B). That is, the inner ring constituent material 73 is cut along the center line L1. At this time, the inner ring constituent material 73 is quenched and tempered by a heating furnace, high-frequency heating, or the like to be hardened and then cut and cut. The end large-diameter portion 76a becomes the large-diameter portion 60 of the inner ring 24, the small-diameter main body portion 74 becomes the small-diameter portion 61 of the inner ring 24, and the outer diameter surface of the tapered portion 75a is the inner rolling surface 28 (29) of the inner ring 24. Become. Further, the inner surface, the both end surfaces 65 and 66, the seal mounting surface 63, and the inner rolling surface 28 (29) are hardened steel cut. The operation of cutting the inner ring constituent material 73 into two may be before heat treatment or after heat treatment. Further, the cutting process may be a conventional process in which turning is performed in a raw material state after the rolling process, instead of the quenching steel cutting after the heat treatment.

  The inner ring constituent material 73 may have a shape as shown in FIG. An inner ring constituent material 73 shown in FIG. 11B includes a large-diameter portion 77 at the central portion in the axial direction, and end small-diameter portions 79a connected to both ends of the large-diameter portion 77 through tapered portions 78a and 78b. 79b.

It will cut the inner component material 73 along the center line L ₁ after forming by plastic working. At this time, the inner ring constituent material 73 is quenched and tempered by a heating furnace, high-frequency heating, or the like to be hardened and then cut and cut. The operation of cutting the inner ring constituent material 73 into two may be before heat treatment or after heat treatment. Further, the cutting process may be a conventional process in which turning is performed in a raw material state after the rolling process, instead of the quenching steel cutting after the heat treatment. Further, in the inner ring constituent material 73 shown in FIG. 11 (a), the cut end surface becomes the end surface 66 on the small diameter side, whereas in the inner ring constituent material 73 shown in FIG. 11 (b), the cut end surface has a large diameter. This is the side end face 65.

  Thus, if the material 70 as shown in FIG. 10 is used, a pair of inner ring | wheels 24 can be shape | molded at once, and productivity can be aimed at.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, the outer ring 25 is formed as a blank. In the embodiment, it is formed by a pipe material, but a round bar-shaped bar material may be cut into a predetermined size, and this cut piece may be formed by hot forging or the like. Further, if the inner ring 24 is a plastic work product formed by cold rolling using martensitic stainless steel, the outer ring 25 may be a conventional outer ring 105 shown in FIG. In addition, as a use of this double row angular bearing, it is not restricted to a wheel bearing apparatus, It can apply to the various apparatuses and mechanisms which use a double row angular bearing.

It is sectional drawing of the double row angular bearing which shows 1st Embodiment of this invention. It is an expanded sectional view of the outer ring of the double row angular bearing. It is a manufacturing-process figure of the outer ring | wheel of the said double row angular bearing. FIG. 3 is a simplified view of a cold rolling machine for forming an outer ring of the double row angular bearing. The fiber flow is shown, (a) is a simplified cross-sectional view of the material, (b) is a simplified cross-sectional view of the product. It is a simplified diagram showing the fiber flow of the main part of the outer ring. It is a simplified diagram of carbide. The fiber flow at the time of using the raw material of another shape is shown, (a) is a simplified sectional view of a material, (b) is a simplified sectional view of a product. It is sectional drawing of the double row angular bearing which shows 2nd Embodiment of this invention. FIG. 10 is a simplified view showing a material for forming an inner ring of the double row angular bearing shown in FIG. 9. The inner ring constituent material for shape | molding the inner ring | wheel of the double row angular bearing shown in FIG. 9 is shown, (a) is a simplified sectional view of a 1st inner ring constituent material, (b) is the simplification of a 2nd inner ring constituent material. It is sectional drawing. It is sectional drawing of the conventional double row angular bearing. It is sectional drawing which shows the manufacturing method of the outer ring | wheel of the conventional double row angular bearing. The fiber flow is shown, (a) is a simplified cross-sectional view of the material, (b) is a simplified cross-sectional view of the product. It is sectional drawing which shows the manufacturing method of the inner ring | wheel of the conventional double row angular bearing. It is a simplification figure showing the fiber flow of the inner ring of the conventional double row angular bearing.

Explanation of symbols

24 inner ring 24A inner ring 24B inner ring 25 outer rings 26, 27 outer rolling surfaces 28, 29 inner rolling surface 30 rolling element 50 outer diameter surface 51 annular recess 71 shoulder

Claims (7)

  An inner ring having a rolling surface on the outer diameter surface, an outer ring having a rolling surface on the inner diameter surface, and a rolling element housed in a freely rolling manner between the outer rolling surface of the outer ring and the inner rolling surface of the inner ring. A double-row angular bearing, wherein at least one of the outer ring and the inner ring is a plastic work product formed by cold rolling using martensitic stainless steel.   The inclination of the fiber flow of the rolling surface of the plastic workpiece is 15 ° or less with respect to the tangential direction of the rolling surface except for a shoulder portion of the rolling surface or the vicinity thereof. Double row angular contact bearings described in 1.   The plastic processed product has C: 0.90 to 1.20% by weight, Si: 1.0% by weight or less, Mn: 1.0% by weight or less, P: 0.040% by weight or less, S: 0.030 Using a blank formed by spheroidizing martensitic stainless steel containing wt% or less, Ni: 0.75 wt% or less, Cr: 16.0 to 18.0 wt%, Mo: 0.75 wt% or less, and plasticity The slope of the fiber flow on the rolling surface of the processed product is 15 ° or less with respect to the tangential direction of the rolling surface except for the shoulder portion of the rolling surface or the vicinity thereof, and at least the hardness of the surface of the rolling surface. The double-row angular bearing according to claim 1, wherein the temperature is 55 to 64 HRC by quenching and tempering.   Plastic processed products are: C: 0.50 to 0.75 wt%, Si: 0.5 wt% or less, Mn: 1.0 wt% or less, P: 0.030 wt% or less, S: 0.030 wt% %, Ni: 0.60 wt% or less, Cr: 11.5 to 13.5 wt%, Mo: 0.50 wt% or less, martensitic stainless steel containing spheroidizing annealed blank, plastic working The inclination of the fiber flow on the rolling surface of the product is 15 ° or less with respect to the tangential direction of the rolling surface except for the shoulder portion of the rolling surface or the vicinity thereof, and at least the hardness of the surface of the rolling surface is at least The double row angular bearing according to claim 1, wherein the double row angular bearing is set to 55 to 64 HRC by quenching and tempering.   5. The compound according to claim 1, wherein the plastic processed product is an outer ring, and a circumferential groove is provided in an axially central portion of an outer diameter surface of the outer ring. Row angular bearing.   The carbide in the plastic processed product is (a + b) / 2 ≦ 50 μm when the major axis length is a and the minor axis length is b. The double-row angular bearing according to claim 1.   The carbide in the plastic processed product is (a + b) / 2 ≦ 30 μm, where a is the major axis length and b is the minor axis length. The double-row angular bearing according to claim 1.

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