JP2008175217A - Double row angular contact ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double row angular contact ball bearing having an enhanced bearing stiffness and an improved assemblability. <P>SOLUTION: A double row angular contact ball bearing of a back-to-back duplex type is composed of crown type holders, in which each holder 9 for holding balls 5 is formed by injection molding a thermoplastic synthetic resin, the holder 9 having a ring portion 13a in one end on the small diameter side thereof and has a pair of holding claws 13b in the peripheral direction on the other end thereof, each claw 13b being opposed to each other at a constant interval and bent in the direction approaching each other, the crown type holder being provided with a pocket 14 formed into a concave spherical surface between the bent claws. The ring portions 13a of the holders 9 are arranged in opposition to each other between the double rows of balls 5, and chamfers 16 are formed on the outer diameter side of the holding claws 6. Accordingly, in the assembly process of inserting the balls 5 into the pockets 14 of the holders 9 to form a subassembly, the balls 5 are prevented from being caught in the edges of the claws, and hence, the abnormal deformation and breaking of the holding claws 13b can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a double-row angular contact ball bearing used in a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and more particularly to a double-row angular contact ball bearing having improved bearing rigidity and improved assembly. .

  Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a double row rolling bearing. In addition, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used.

  Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. A second generation structure in which a vehicle body mounting flange or a wheel mounting flange is directly formed on the outer periphery of the side member, a third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or a hub wheel It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the constant velocity universal joint.

  A double row angular contact ball bearing 50 shown in FIG. 5 is a typical example. This double row angular contact ball bearing 50 is referred to as a first generation, and an outer ring 51 having an arcuate double row outer raceway surface 51a, 51a formed on the inner circumference, and the double row outer raceway surface 51a on the outer circumference. , 51a, a pair of inner rings 52, 52 formed with an arcuate inner rolling surface 52a, double-row balls 53, 53 accommodated between both rolling surfaces, and rolling these balls 53 Retainers 54 and 54 that are freely held, and seals 55 and 56 that are attached to both ends of the outer ring 51 are provided.

  The double-row angular contact ball bearing 50 is set in a state where the end surfaces on the small diameter side (front side) of the pair of inner rings 52 and 52 are abutted to each other, and constitutes a so-called back-to-back type double-row angular contact ball bearing. The outer ring 51 or the seals 55 and 56 attached to the outer ring 51 and the inner ring 52 prevent leakage of the lubricating grease sealed inside the bearing and intrusion of rainwater and dust from the outside into the bearing. is doing.

  In this type of double-row angular ball bearing 50, balls 53 are incorporated in a retainer 54 in advance, and these sub-assemblies are respectively inserted into the double-row outer raceway surfaces 51a and 51a from both sides of the outer ring 51, thereby providing a predetermined amount of grease. Is enclosed. Thereafter, a pair of inner rings 52 and 52 are fitted and inserted from both sides of the outer ring 51, and seals 55 and 56 are attached to openings in an annular space formed between the outer ring 51 and the inner ring 52.

  Here, the cage 54 is generally formed by injection-molding a thermoplastic synthetic resin. However, a so-called window type cage having annular portions 54a and 54b at both ends has a rigidity of the cage 54. Although it is high and has excellent holding ability of the ball 53, in the double-row angular contact ball bearing 50 used in this type of wheel bearing device, the large-diameter annular portion 54b may interfere with the seals 55 and 56. Therefore, inevitably, the ball pitch P1 in the double-row balls 53, 53 must be restricted to be small. Therefore, in order to increase the ball pitch P1 and increase the bearing rigidity, there is a double row angular ball bearing 57 as shown in FIG.

  This double-row angular ball bearing 57 includes an outer ring 58, a pair of inner rings 59, 59, double-row balls 53, 53, cages 60, 60 that hold these balls 53 in a freely rolling manner, and both ends of the outer ring 58. Seals 55 and 56 attached to the parts are provided.

  As shown in FIG. 7, the retainer 60 has an annular portion 61a at one end on the small diameter side of the retainer body 61, and a pair of retaining claws 61b facing the other end at regular intervals in the circumferential direction. 61b is formed. The holding claw 61b is provided with a pocket 62 which is curved in a direction approaching each other and formed in a concave spherical surface therebetween. Further, a recess 63 is formed between the rear surfaces of the holding claws 61b so that the holding claws 61b rise, and appropriate elasticity is imparted to the holding claws 61b. This holding claw 61b is elastically deformed to form a so-called snap-on type crown-shaped cage in which the ball 53 is mounted and the ball 53 is held through a predetermined pocket clearance. By arranging the annular portions 61a of the cage 60 so as to face each other, the ball pitch P2 can be maximized without interfering with the seals 55 and 56 as shown in FIG. Stiffness can be increased. However, there is no prior art document information to be described because the prior art does not relate to a known literature invention.

  However, in such a conventional cage 60, the ball pitch P2 of the bearing can be increased by avoiding interference with the seals 55 and 56. However, the ball 53 is inserted into the pocket 62 of the cage 60 and the sub-assembly is performed. There is a problem in the assembly process. That is, since the tip of the holding claw 61b is an edge, it is difficult to assemble by being caught when the ball 53 is inserted, and not only the workability is lowered but also there is a risk of abnormal deformation or loss. Further, when the size and number of balls 53 are increased in order to increase the load capacity of the bearing, the thickness of the holding claws 61b inevitably decreases, and this tendency becomes stronger.

  This invention is made | formed in view of such a situation, and it aims at providing the double row angular contact ball bearing which improved the bearing rigidity and improved the assembly property.

  In order to achieve the object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and an outer rolling surface of the double row on the outer periphery. An inner member in which a double row inner rolling surface facing the inner member is formed, and a double row of the inner member and the outer member that are accommodated so as to roll freely between the rolling surfaces of the inner member and the outer member. A ball and a seal attached to an opening of an annular space formed between the outer member and the inner member, and the cage is formed by injection molding a thermoplastic synthetic resin. The retainer has an annular portion at one end on the small diameter side, and a pair of holding claws that are opposed to each other at regular intervals in the circumferential direction are formed at the other end, and the holding claws are curved in a direction approaching each other, Back-to-back made up of a snap-on type crown cage with a pocket formed in the concave spherical surface in between In the double row angular contact ball bearing type, the annular portion of the retainer is the disposed facing between rows of balls double row chamfer on the outer diameter side of the retaining claws of the cage are formed.

  Thus, the cage for holding the ball is formed by injection molding a thermoplastic synthetic resin, and has an annular portion at one end portion on the small diameter side of the cage, and at the other end portion in the circumferential direction. A pair of holding claws facing each other at regular intervals, the holding claws curved in a direction approaching each other, and a back surface composed of a snap-on type crown-shaped cage with a pocket formed in a concave spherical surface between them In the double row angular contact ball bearings of the mating type, the annular portion of the cage is arranged to face between the double row of ball rows, and a chamfer is formed on the outer diameter side of the holding claw of the cage. In the assembly process of inserting the ball into the pocket and making it a sub-assembly, it is possible to prevent the ball from being caught at the edge portion, and to prevent abnormal deformation and loss of the holding claws. Accordingly, it is possible to provide a double-row angular contact ball bearing that avoids interference with the seal, increases the ball pitch to the maximum, increases the bearing rigidity, and improves the assemblability.

  Preferably, as in the invention described in claim 2, the inner member integrally has a wheel mounting flange for mounting the wheel at one end, an outer side inner rolling surface on the outer periphery, and the inner side. A hub ring in which a small diameter step portion extending in the axial direction from the rolling surface is formed, and an inner ring in which a small diameter step portion of the hub ring is press-fitted through a predetermined shimoshiro and an inner side inner rolling surface is formed on the outer periphery. If it is comprised by this, while achieving weight reduction and a compactness, a highly rigid hub ring can be obtained and the durability as a wheel bearing apparatus can be improved.

  Further, as in the invention according to claim 3, if the pitch circle diameter of the outer side ball row of the double row of ball rows is set larger than the pitch circle diameter of the inner side ball row. The number of balls in the outer side ball row can be set larger than the number of balls in the inner side ball row, and the bearing rigidity of the outer side portion can be further increased compared to the inner side by effectively utilizing the bearing space. The life of the bearing can be extended.

  The double-row angular contact ball bearing according to the present invention includes an outer member integrally formed with an outer rolling surface of a double row on an inner circumference, and an inner rolling of a double row facing the outer rolling surface of the double row on an outer circumference. An inner member formed with a running surface, a double row of balls accommodated between the rolling surfaces of the inner member and the outer member via a cage, and the outer member; And a seal mounted in an opening of an annular space formed between the inner member and the retainer is formed by injection molding a thermoplastic synthetic resin, and a small diameter side of the retainer is formed. A pair of holding claws that have an annular portion at one end and are opposed to each other at regular intervals in the circumferential direction are formed on the other end, and the holding claws are curved in a direction approaching each other and formed into a concave spherical surface therebetween Back-to-back type double row angle composed of a snap-on type crown cage with pockets In the ball bearing, the annular portion of the cage is disposed between the double rows of ball rows, and a chamfer is formed on the outer diameter side of the holding claw of the cage. In the assembly process in which the ball is inserted and used as a sub-assembly, it is possible to prevent the ball from being caught at the edge portion and to prevent abnormal deformation and loss of the holding claw. Accordingly, it is possible to provide a double-row angular contact ball bearing that avoids interference with the seal, increases the ball pitch to the maximum, increases the bearing rigidity, and improves the assemblability.

  An outer member that has a body mounting flange that is attached to the vehicle body on the outer periphery, an arcuate double-row outer rolling surface is formed integrally on the inner periphery, and a wheel for attaching the wheel to the outer end. A wheel mounting flange is integrally formed, and an arc-shaped inner rolling surface facing one of the double row outer rolling surfaces and a small-diameter step portion extending in the axial direction from the inner rolling surface are formed on the outer periphery. An inner member comprising a hub ring and an inner ring that is press-fitted into a small-diameter step portion of the hub ring via a predetermined shimiro and has an inner race surface facing the other of the outer race surfaces of the double row on the outer periphery. An annular space formed between the outer ring and the inner ring, and a double row of balls accommodated between the rolling surfaces of the inner member and the outer member via a cage. A seal attached to the opening, and the cage injection-molds the thermoplastic synthetic resin. And a pair of holding claws that are opposed to each other at a constant interval in the circumferential direction are formed at one end of the cage on the small diameter side, and the holding claws approach each other. In a wheel bearing device composed of a back-to-back type double row angular contact ball bearing composed of a snap-on type crown-shaped cage having a pocket formed in a concave spherical surface therebetween, An annular portion of the cage is disposed opposite to the double row of ball rows, and a chamfer is formed on the outer diameter side of the holding claw of the cage.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device equipped with a double-row angular ball bearing according to the present invention, FIG. 2 shows the cage of FIG. 1, and (a) is (b). Sectional drawing along the II-II line | wire, (b) is a front view, FIG. 3 is a perspective view of a holder | retainer same as the above.

  This wheel bearing device is for a driven wheel called the third generation, and is composed of a double-row angular ball bearing 1 and a hub ring 2. The double-row angular ball bearing 1 includes an inner member 3, an outer member 4, and double-row balls 5 and 5, which are accommodated between the members 3 and 4 so as to roll freely. The inner member 3 includes a hub ring 2 and an inner ring 6 that is press-fitted into the hub ring 2 via a predetermined scissors.

  The hub wheel 2 integrally has a wheel mounting flange 7 for mounting a wheel (not shown) at an end portion on the outer side, and one (outer side) arcuate inner rolling surface 2a on the outer periphery. A small-diameter step portion 2b is formed through an axial portion extending in the axial direction from the inner rolling surface 2a. Hub bolts 7a are planted on the wheel mounting flange 7 in a circumferentially uniform manner, and circular holes 7b are formed between the hub bolts 7a. The circular hole 7b not only contributes to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 7b in the assembly / disassembly process of the apparatus, and the work can be simplified.

  The inner ring 6 is formed with the other (inner side) arcuate inner rolling surface 6a on the outer periphery and is press-fitted into the small-diameter step portion 2b of the hub wheel 2 to constitute a back-to-back type double-row angular ball bearing. . Further, the inner ring 6 is fixed in the axial direction by a caulking portion 8 formed by plastic deformation of an end portion of the small diameter step portion 2b. Thereby, while achieving weight reduction and compactness, the rigidity of the hub wheel 2 becomes high and durability can be improved. The inner ring 6 and the ball 5 are made of high carbon chrome steel such as SUJ2 (JIS G 4805), and are hardened in the range of 58 to 64 HRC up to the core part by quenching.

  The hub wheel 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon, such as S53C, and includes an inner rolling surface 2a and a base portion 7c on the inner side of the wheel mounting flange 7 to a small diameter step portion 2b. Thus, a predetermined hardened layer is formed with a surface hardness in the range of 58 to 64 HRC by induction hardening. The caulking portion 8 is kept in the surface hardness after forging. This has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 7, improves the fretting resistance of the small-diameter stepped portion 2b serving as the fitting portion of the inner ring 6, and is caulked. It is possible to prevent the occurrence of minute cracks or the like during plastic processing of the portion 8.

  The outer member 4 integrally has a vehicle body mounting flange 4c to be attached to a knuckle (not shown) on the outer periphery, and has an arcuate shape on the outer side facing the inner rolling surface 2a of the hub wheel 2 on the inner periphery. The outer rolling surface 4a and the inner arcuate outer rolling surface 4b facing the inner rolling surface 6a of the inner ring 6 are integrally formed. This outer member 4 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 4a and 4b have a surface hardness in the range of 58 to 64HRC by induction hardening. A predetermined hardened layer is formed. The double-row balls 5 and 5 rows are accommodated between the rolling surfaces, and are held by the cages 9 and 10 so as to roll freely. Further, seals 11 and 12 are attached to the opening of the annular space formed between the outer member 4 and the inner member 3, and leakage of grease sealed inside the bearing to the outside, and rainwater from the outside. And dust are prevented from entering the bearing.

  In this embodiment, the pitch circle diameter PCDo of the five rows of balls on the outer side is set larger than the pitch circle diameter PCDi of the five rows of balls on the inner side. The outer diameters of the balls 5 and 5 are the same, but due to the difference in pitch circle diameters PCDo and PCDi, the number of balls in the outer five rows of balls is set larger than the number of balls in the inner five balls. ing. As a result, the bearing space can be effectively utilized to increase the bearing rigidity of the outer side portion compared to the inner side, and the life of the bearing can be extended.

  Here, the cages 9 and 10 are formed by injection molding by adding a reinforcing material such as GF (glass fiber) based on a thermoplastic resin such as PA (polyamide) 66. As shown in FIGS. 2 and 3, the cages 9 and 10 have an annular portion 13a at one end on the small diameter side of the cage body 13 having the tapered portions 13c and 13d, and in the circumferential direction at the other end. A pair of holding claws 13b and 13b that are opposed to each other at a constant interval are formed. This holding claw 13b is curved in a direction approaching each other, and has a pocket 14 formed in a concave spherical surface therebetween. Moreover, the recessed part 15 where the holding nail | claw 13b rises is formed between the back surfaces of the holding nail | claw 13b, and moderate elasticity is provided to the holding | maintenance claw 13b. The holding claw 13b is elastically deformed to form a so-called snap-on type crown-type cage in which the ball 5 is mounted and the ball 5 is held through a predetermined pocket clearance. Thereby, it can hold | maintain so that the ball | bowl 5 may not drop | omit to an internal diameter side.

  In the present embodiment, a linear chamfer 16 is formed on the outer diameter side of the holding claw 13b. The edge portion of the holding claw 13b is removed by the chamfering 16, and the ball 5 is prevented from being caught at the edge portion in the assembling process in which the ball 5 is inserted into the pockets 14 of the cages 9 and 10 to form a sub-assembly. Abnormal deformation and loss of the nail 13b can be prevented. Therefore, by arranging the annular portions 13a of the cages 9 and 10 to face each other, interference with the seals 11 and 12 can be avoided, and the ball pitch P can be maximized to increase the bearing rigidity. A wheel bearing device with improved assemblability can be provided.

Next, the assembly method of the wheel bearing device according to the present embodiment will be described in detail with reference to FIG.
First, the balls 3 are held by the cages 9 and 10 to form a subassembly, and the inner subassembly is fitted and inserted into the inner side rolling surface 4b of the outer member 4 placed vertically. The outer side sub-assemblies are respectively inserted into the outer side outer rolling surfaces 4a. Thereafter, the seal 11 is press-fitted into the outer end of the outer member 4, and grease is sealed by inserting a grease sealing jig (not shown) into the outer member 4. The hub ring 2 is inserted into the outer member 4, and the inner ring 6 is press-fitted into the small-diameter step portion 2 b of the hub ring 2. Finally, the inner ring 6 is fixed in the axial direction by swinging and caulking the end of the small diameter step 2b.

  Here, the third generation structure is illustrated, but the present invention is not limited to this, and can be applied to the first generation to fourth generation structures. FIG. 4 shows a double-row angular contact ball bearing 17 showing a first generation structure. This double-row angular contact ball bearing 17 is used in a wheel bearing device, and is fitted between a hub wheel and a knuckle (not shown). It is supported rotatably. In addition, the same code | symbol is attached | subjected to the site | part which has the same component same part as embodiment mentioned above, or the same function, and the detailed description is abbreviate | omitted.

  This double row angular contact ball bearing 17 includes an outer ring (outer member) 18 having an arcuate double row outer raceway surface 18a, 18a formed on the inner circumference, and a double row outer raceway surface 18a, 18a on the outer circumference. A pair of inner rings (inner members) 19, 19 formed with an arcuate inner rolling surface 19 a opposite to each other, double-row balls 5, 5 accommodated between both rolling surfaces, and these balls 5 5 and 5 are provided. The holders 20 and 20 hold the roller 5 in a rollable manner, and the seals 21 and 12 attached to both ends of the outer ring 18.

  The outer ring 18 is made of high carbon chrome bearing steel such as SUJ2 or carburized steel. The high carbon chrome bearing steel is tempered at 820 to 860 ° C. and then tempered at 160 to 200 ° C., and the core portion is in the range of 58 to 64 HRC. Has been cured. In the case of carburized steel, the surface is hardened in the range of 58 to 64 HRC. On the other hand, the inner ring 19 is made of high carbon chrome bearing steel such as SUJ2 or carburized steel, like the outer ring 18, and the high carbon chrome bearing steel is hardened to the core in the range of 58 to 64 HRC. Is cured in the range of 58 to 64 HRC.

  This double row angular ball bearing 17 is set in a state where the small diameter side (front side) end faces 19b, 19b of the pair of inner rings 19, 19 are abutted, and constitutes a back-to-back type double row angular ball bearing. Yes. Further, the seals 21 and 12 attached to the opening portion of the annular space formed between the outer ring 18 and the inner ring 19 cause leakage of the lubricating grease enclosed in the bearing to the outside, rainwater, dust, etc. from the outside. Is prevented from entering the inside of the bearing.

  Here, the cage 20 is formed by injection molding by adding a reinforcing material such as GF (glass fiber) based on a thermoplastic resin such as PA66. The cage 20 has an annular portion 22 a at one end of the cage body 22 on the small diameter side. The cage main body 22 includes tapered portions 13c and 13d. Further, the annular portion 22a is disposed so as to face between the five rows of double rows of balls. A pair of holding claws 22b and 22b are formed at the other end of the cage main body 22 so as to face each other at regular intervals in the circumferential direction. The holding claw 22b is curved in a direction approaching each other, and includes a pocket 14 formed in a concave spherical surface therebetween. Moreover, the recessed part 15 where the holding nail | claw 22b stands is formed between the back surfaces of the holding nail | claw 22b, and moderate elasticity is provided to the holding | maintenance claw 13b. The holding claw 13b is elastically deformed to form a snap-on crown-type cage in which the ball 5 is mounted and the ball 5 is held through a predetermined pocket clearance.

  Also in this embodiment, as described above, since the chamfer 16 is formed on the holding claw 22b of the cage 20, it is possible to prevent the ball 5 from being caught at the edge portion in the assembly process of sub-assembling the cage 20 and the ball 5. It is possible to prevent abnormal deformation and loss of the holding claws 22b, avoid interference with the seals 21 and 12, and increase the ball pitch P to the maximum to increase the bearing rigidity.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The double row angular contact ball bearing according to the present invention can be applied to a wheel bearing device having a first to fourth generation structure.

It is a longitudinal section showing one embodiment of a wheel bearing device provided with a double row angular contact ball bearing concerning the present invention. 1 shows the cage of FIG. 1, (a) is a cross-sectional view taken along line II-II of (b), and (b) is a front view. It is a perspective view showing the maintenance machine concerning the present invention. It is a longitudinal cross-sectional view which shows other embodiment of the double row angular contact ball bearing which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional double row angular contact ball bearing. It is a longitudinal cross-sectional view which shows the other conventional double row angular contact ball bearing. It is a perspective view which shows the holder | retainer of FIG.

Explanation of symbols

1, 17 ········· Double row angular contact ball bearing 2 ·············································· ... Small-diameter step portion 3 ···························· Outside members 4a, 4b, 18a ... Outer rolling surface 4c・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Balls 6, 19 ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting Flange 7a ... Hub bolt 7b ... Round hole 7c ... Base 8 ... Caulking portions 9, 10 ......... Cage 11, 12, 21 ... Seals 13, 22 ... Cage body 13a, 22a ... Annular portion 13b , 22b... Holding claws 13c, 13d・ ・ ・ Tapered part 14 ・ ・ ・ ・ ・ ・ Pocket 15 ・ ・ ・ ・ ・ ・ Recessed part 16 ・ ・ ・ ・ ・ ・ Chamfer 50, 57 ・ ・ ・ ・ ・ ・・ Double-row angular contact ball bearings 51, 58... Outer ring 51 a ... Outer rolling surface 52, 59 ... Inner ring 52 a ... .. Inner rolling surface 53... Balls 54 and 60... Retainers 54 a, 54 b and 61 a Annular portions 55 and 56. ·········································································································· , P1, P2 ... Ball pitch PCDi ... ... Pitch circle diameter of the inner side ball row PCDo ... ... Pitch circle of the outer side ball row Diameter

Claims (3)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
An inner member in which a double row inner rolling surface facing the outer row rolling surface of the double row is formed on the outer periphery;
A double row of balls accommodated between the rolling surfaces of the inner member and the outer member via a retainer between the rolling surfaces;
A seal attached to an opening of an annular space formed between the outer member and the inner member;
The cage is formed by injection molding a thermoplastic synthetic resin,
The retainer has an annular portion at one end on the small diameter side, and a pair of retaining claws that are opposed to each other at regular intervals in the circumferential direction are formed at the other end, and the retaining claws are curved in a direction approaching each other, In back-to-back type double row angular contact ball bearings composed of snap-on type crown cages with pockets formed in concave spherical surfaces,
A double-row angular contact ball bearing, wherein an annular portion of the cage is arranged opposite to the double row of ball rows, and a chamfer is formed on an outer diameter side of a holding claw of the cage.   The inner member integrally has a wheel mounting flange for mounting a wheel at one end portion, and an outer side inner rolling surface and a small-diameter step portion extending in the axial direction from the inner rolling surface are formed on the outer periphery. 2. A double-row angular ring as set forth in claim 1, wherein the double-row angular ring is constituted by a hub ring and an inner ring that is press-fitted into a small-diameter step portion of the hub ring via a predetermined shimiro and has an inner side inner rolling surface formed on the outer periphery. Ball bearing.   The double row angular contact ball bearing according to claim 1 or 2, wherein a pitch circle diameter of an outer side ball row of the double row ball rows is set larger than a pitch circle diameter of an inner side ball row.

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