JP6661308B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device that rotatably supports wheels of an automobile or the like with respect to a suspension device, particularly, in a self-retained structure in which an inner ring is fixed by swinging and caulking of a hub wheel, a large end face side of the inner ring is provided. The chamfered shape was devised to make it difficult for nicks to occur in the manufacturing process, and even if hoop stress was generated in the inner ring due to crimping, the occurrence of delayed fracture due to nicks was suppressed and durability was improved. The present invention relates to a bearing device for a wheel.

  2. Description of the Related Art Wheel bearing devices for vehicles such as automobiles rotatably support wheels to a suspension device via double-row rolling bearings, and include a drive wheel and a driven wheel. For example, the conventional wheel bearing device shown in FIG. 5 is referred to as a third generation for a driven wheel, and includes an inner member 51 and an outer member 52, and a plurality of members rotatably housed between the two members 51 and 52. Row of balls 53, 53. The inner member 51 includes a hub wheel 54 and an inner wheel 55 which is press-fitted into the hub wheel 54 via a predetermined shim.

  The hub wheel 54 integrally has a wheel mounting flange 56 for mounting a wheel (not shown) at one end thereof, and hub bolts 56a for fixing the wheel at circumferentially equal positions of the wheel mounting flange 56 are implanted. Has been established. Further, on the outer periphery of the hub wheel 54, one arc-shaped inner rolling surface 54a and a small-diameter step portion 54b extending in the axial direction from the inner rolling surface 54a are formed. The inner race 55 having the other arc-shaped inner rolling surface 55a formed on the outer periphery is press-fitted into the small-diameter step portion 54b. The inner ring 55 is fixed in the axial direction while a predetermined bearing preload is applied by a caulking portion 57 formed by plastically deforming the end of the small-diameter step portion 54b of the hub wheel 54 radially outward. .

  The outer member 52 integrally has a vehicle body mounting flange 52b for attaching to a knuckle (not shown) on the outer periphery, and has an arcuate shape on the inner periphery facing the inner rolling surfaces 54a, 55a of the inner member 51. Double rows of outer rolling surfaces 52a, 52a are integrally formed. Double rows of balls 53, 53 are accommodated between the respective rolling surfaces 52a, 54a and 52a, 55a, and these double rows of balls 53, 53 are held rotatably by retainers 58, 58. .

  Here, on the inner peripheral surface of the inner end portion of the inner ring 55, there is formed an inclined surface 59 having a conical concave shape whose inclination angle θ1 is about 20 to 60 degrees, the inner diameter increasing toward the inner end opening. The caulking portion 57 is formed by plastically deforming the end of the small-diameter step portion 54b so as to be in close contact with the inclined surface 59. Thus, the amount of deformation of the caulking portion 57 can be reduced. That is, when the caulking portion 57 is formed, it is sufficient that the caulking portion 57 is deformed by the inclination angle θ1, thereby suppressing the distortion generated in the caulking portion 57 and suppressing the damage such as cracking to the caulking portion 57. (For example, see Patent Document 1).

  However, in this type of caulking-type wheel bearing device, the inner ring 55 is subjected to stress in the radially enlarged direction by squeezing and caulking with the hub wheel 54, but in the above-described conventional wheel bearing device. Due to the inclined surface 59 of the inner ring 55, a force applied to the inner ring 55 radially outward due to plastic deformation, that is, a so-called hoop stress is increased, and the deformation of the inner ring 55 may be excessively damaged.

  Further, in the manufacturing process until the inner ring 55 is incorporated into the bearing, each part of the inner ring 55 may be damaged. In particular, when the inner rings 55 collide with each other or the inner ring 55 collides with an external interference object such as a transport facility, if the inclination angle θ1 of the inclined surface 59 of the inner ring 55 is as small as about 20 to 60 degrees, the large end surface 55b and the inclined surface The intersection angle θ2 with the inner ring 59 is about 120 to 160 degrees, and the edge of this portion may collide with another inner ring 55 and cause a flaw. In this case, in a state where the hoop stress is applied to the outer surface of the inner ring 55, there is a possibility that stress corrosion cracking starting from this bruise, that is, so-called delayed fracture may occur.

  As a solution to these problems, a wheel bearing device as shown in FIG. 6 is known. In this wheel bearing device, an inclined surface 62 having an inclination angle θ3 of 101 to 179 degrees is gradually formed radially outward on the large end surface 61 of the inner ring 60 toward the inner side, and is in close contact with the inclined surface 62. Thus, a caulked portion 63 is formed. As a result, the component force of the processing force generated by the swing caulking can be reduced and the inner ring 60 can be prevented from being elastically deformed radially outward, so that the hoop stress of the inner ring 60 can be reduced and the inner ring 60 can be reduced. (For example, see Patent Document 2).

Japanese Patent No. 3855315 JP 2010-42763 A

  In the inner ring 60, the intersection angle θ4 between the large end surface 61 and the inclined surface 62 becomes as large as 140.5 to 179.5 degrees in the manufacturing process and the like, and the edge of this portion is damaged compared with the above-described inner ring 55. However, the probability that a dent will occur on the inclined surface 62 of the inner ring 60 that is greatly opened increases. As a result, there is a problem that the possibility of occurrence of delayed destruction starting from a strike increases.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and restricts an angle of an edge portion between a large end surface of an inner ring and a chamfered portion to reduce a stress at the time of collision with an interfering object. Focusing on chamfered shapes that do not easily damage the wheel, even if hoop stress is generated in the inner ring due to crimping, the occurrence of delayed fracture due to the damage is suppressed and the durability of the wheel bearing device is improved. The purpose is to provide.

In order to achieve the above object, an invention according to claim 1 of the present invention is directed to an outer member having a double-row outer rolling surface integrally formed on an inner periphery thereof, and a wheel for attaching a wheel to one end. A hub wheel having a mounting flange integrally formed with a small-diameter stepped portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter stepped portion of the hub wheel; An inner member having a double row of inner rolling surfaces opposed to the rolling surface; and a double row rotatably housed between the outer rolling face of the double row and the inner rolling face of the double row. The inner ring is axially fixed by a caulking portion formed by plastically deforming the end of the small-diameter stepped portion of the hub wheel radially outward. At the same time, a chamfered portion is formed at the inner diameter end of the inner ring on the large end face side, and the chamfered portion is formed into an arcuate surface. Gradually is constituted by the inclined surface inclined inner side toward the tangent of the circular arc surface radially outward, setting the angle a of the large end face of the inner ring and the extended line of the inclined surface of the chamfer 20 degrees or less The caulking portion includes a chamfered portion of the inner ring, and is formed in a state of being in close contact with a large end surface of the inner ring.

In this manner, the outer member having the double row of outer rolling surfaces integrally formed on the inner periphery and the wheel mounting flange for mounting the wheel at one end are integrally formed, and the small diameter step extending in the axial direction on the outer periphery. A hub wheel having a portion formed therein and at least one inner ring press-fitted into a small-diameter step portion of the hub wheel, and a double-row inner rolling surface opposed to a double-row outer rolling surface is formed on the outer periphery. First to third generation wheel bearings having an inner member, and double-row rolling elements rotatably accommodated between double-row outer rolling surfaces and double-row inner rolling surfaces. In the device, the inner ring is axially fixed by a caulking portion formed by plastically deforming the end of the small-diameter step portion of the hub wheel radially outward, and the inner ring is chamfered on the inner diameter end on the large end surface side of the inner ring. The chamfered portion is formed with an arc surface and an inner surface gradually extending radially outward from a tangent to the arc surface. Is composed of the inclined surface inclined, the angle a of the large end face of the extension and the inner ring of the inclined surface of the chamfered portion is set to 20 degrees or less, caulking portions include inner chamfers, the inner ring of the large Since it is formed in a state of being in close contact with the end surface, the intersection angle between the large end surface of the inner ring and the inclined surface increases, and in the manufacturing process, if the inner rings or the inner ring collide with an external interference object such as transfer equipment, this Occurrence of a flaw due to the edge of the portion can be suppressed.

  Preferably, if the intersection between the large end surface of the inner race and the inclined surface of the chamfered portion is smoothly rounded, it is possible to prevent the occurrence of burrs. In addition, it is possible to suppress the occurrence of damage due to the edge of this portion.

The wheel bearing device according to the present invention has an outer member integrally formed with a double-row outer rolling surface on the inner periphery, and a wheel mounting flange for mounting a wheel at one end, and an outer periphery integrally formed on the outer periphery. A hub wheel formed with a small-diameter stepped portion extending in the axial direction, and at least one inner ring press-fitted into the small-diameter stepped portion of the hub wheel; For a wheel comprising: an inner member having a rolling surface formed thereon; and a double-row rolling element rotatably accommodated between the outer rolling surface of the double row and the inner rolling surface of the double row. In the bearing device, the inner ring is axially fixed by a caulking portion formed by plastically deforming the end of the small-diameter step portion of the hub wheel radially outward, and the inner diameter of the inner ring on the large end face side of the inner ring. A chamfer is formed at the end, and the chamfer is radially outward from the arc surface and a tangent to the arc surface. Towards is gradually composed inclined surface inclined inner side, wherein the angle a of the large end face of the extension and the inner ring of the inclined surface of the chamfered portion is set below 20 degrees, the caulking portion of the inner ring Including the chamfered portion, since it is formed in a state of being in close contact with the large end surface of the inner ring, the intersection angle between the large end surface of the inner ring and the inclined surface becomes large, and in the manufacturing process, the inner rings and the inner ring are used for transport equipment and the like. When it collides with an external interference object, it is possible to suppress the occurrence of a flaw due to the edge of this portion.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. FIG. 2A is an enlarged view of a main part showing a caulking part in FIG. 1, and FIG. 2B is an enlarged view of a main part showing a chamfered part of an inner ring in FIG. It is a longitudinal section showing a 2nd embodiment of the bearing device for wheels concerning the present invention. It is a longitudinal cross-sectional view which shows the modification of the bearing device for wheels of FIG. It is a longitudinal section showing the conventional wheel bearing device. It is a longitudinal section showing other conventional wheel bearing devices.

  An outer member integrally having a vehicle body mounting flange for being attached to a knuckle on an outer periphery, a double row outer rolling surface being integrally formed on an inner periphery, and a wheel mounting flange for attaching a wheel to one end. A hub wheel integrally formed and formed on its outer periphery with an inner rolling surface facing one of the outer rows of the double row, a small-diameter step extending axially from the inner rolling surface, and the hub wheel An inner member comprising an inner ring having an inner race surface formed by press-fitting into a small-diameter step portion and having an inner race surface facing the other of the outer race surfaces in the double row on the outer periphery, and both the inner member and the outer member. A double-row rolling element rotatably accommodated between the rolling surfaces via a retainer, and a caulking portion formed by plastically deforming the end of the small-diameter step portion radially outward. A wheel bearing device in which the inner ring is axially fixed to the hub wheel, A chamfered portion is formed at the inner diameter end portion on the surface side, and the chamfered portion is constituted by an arcuate surface and an inclined surface gradually inclined radially outward from a tangent to the arcuate surface toward the inner side, wherein the chamfered portion is formed. The inclination angle of the inclined surface is set to 20 degrees or less, and the intersection between the large end surface of the inner ring and the inclined surface of the chamfered portion is smoothly rounded.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 (a) is an enlarged view of a main part showing a caulking portion of FIG. 1, and FIG. It is a principal part enlarged view which shows the chamfered part of the inner ring of a). In the following description, a side closer to the outside of the vehicle when assembled to the vehicle is referred to as an outer side (left side in FIG. 1), and a side closer to the center is referred to as an inner side (right side in FIG. 1).

  The wheel bearing device shown in FIG. 1 has a third-generation structure on the driven wheel side, and has an inner member 1 and an outer member 2 and a double-row rolling element rotatably accommodated between the two members 1 and 2. (Balls) 3 and 3. The inner member 1 includes a hub wheel 4 and an inner wheel 5 press-fitted into the hub wheel 4 via a predetermined shim.

  The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at an end on the outer side, and a hub bolt for fixing the wheel at a circumferentially equidistant position of the wheel mounting flange 6. 6a is planted. On the outer periphery of the hub wheel 4, one (outer side) inner rolling surface 4a having an arc-shaped cross section and a small axial step portion extending in the axial direction from the inner rolling surface 4a via a shoulder 4c. 4b is formed. The inner ring 5 having the other (inner side) arcuate inner rolling surface 5a formed on the outer periphery has a small diameter with its small end surface (front end surface) 5c abutting against the shoulder 4c of the hub wheel 4. It is press-fitted into the step 4b. The inner ring 5 is fixed in the axial direction while a predetermined bearing preload is applied by a caulking portion 7 formed by plastically deforming the end of the small-diameter step portion 4b of the hub wheel 4 radially outward. .

  The outer member 2 integrally has a vehicle body mounting flange 2b for mounting to a knuckle (not shown) on the outer periphery, and has a circular cross section facing the inner rolling surfaces 4a, 5a of the inner member 1 on the inner periphery. The arcuate double rows of outer rolling surfaces 2a, 2a are integrally formed. Double rows of rolling elements 3, 3 are accommodated between the rolling surfaces 2a, 4a and 2a, 5a, and these double rows of rolling elements 3, 3 are held by the retainers 8, 8 so as to roll freely. ing.

  Further, seals 9 and 10 are attached to openings of an annular space formed between the outer member 2 and the inner member 1, and leakage of lubricating grease sealed in the bearing and rainwater or dust from the outside. Are prevented from entering the inside of the bearing. Here, a wheel bearing device constituted by a double-row angular contact ball bearing using the rolling element 3 as a ball is exemplified, but the present invention is not limited to this, and is constituted by a double-row tapered roller bearing using a tapered roller for the rolling element. May be used.

  The hub wheel 4 is formed of a medium-high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and includes the inner rolling surface 4a on the outer side and the wheel mounting flange 6 serving as a seal land portion of the seal 9. From the inner base 6b to the small diameter step 4b, the surface hardness is hardened by induction hardening so that the surface hardness is in the range of 50 to 64 HRC. The caulked portion 7 is an unquenched portion having a material surface hardness after forging.

  On the other hand, the inner ring 5 is made of high carbon chromium bearing steel such as SUJ2, and has been hardened to the core by subbing quenching in the range of 58 to 64 HRC. The rolling elements 3 are made of high carbon chromium bearing steel such as SUJ2, and have been hardened up to the core portion by hardening in the range of 62 to 67 HRC by quenching. Similarly to the hub wheel 4, the outer member 2 is made of medium-high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and at least the double-row outer rolling surfaces 2a, 2a The surface hardness is hardened by quenching to a range of 58 to 64 HRC.

  In the present embodiment, the outer seal 9 of the seals 9 and 10 includes a core metal 11 press-fitted into the inner periphery of the outer end of the outer member 2 via a predetermined shim, and It is composed of an integral seal composed of a seal member 12 integrally joined by vulcanization bonding or the like. The core metal 11 is formed by pressing a rust-proof cold-rolled steel plate (such as JIS standard SPCC).

  On the other hand, the seal member 12 is made of synthetic rubber such as NBR (acrylonitrile-butadiene rubber), and is integrally joined to the core metal 11 by vulcanization adhesion. The seal member 12 has a pair of side lips 12a and 12b formed to be inclined outward in the radial direction, and a grease slip 12c formed to be inclined toward the inside of the bearing. A base 6b on the inner side of the wheel mounting flange 6 is formed in a curved surface having an arc-shaped cross section, and the side lips 12a and 12b and the grease slip 12c are slidably contacted with the base 6b with a predetermined shim.

  The material of the seal member 12 is not limited to NBR, but includes, for example, HNBR (hydrogenated acrylonitrile / butadiene rubber) and EPDM (ethylene propylene rubber), which are excellent in heat resistance, as well as heat resistance and chemical resistance. ACM (polyacryl rubber), FKM (fluoro rubber), silicon rubber, or the like, which is excellent in water resistance, can be exemplified.

  2A, the inner side seal 10 is a so-called pack seal composed of an annular seal plate 13 and a slinger 14, which are arranged to face each other. The seal plate 13 includes a core 15 mounted on the outer member 2 and a seal member 16 integrally joined to the core 15 by vulcanization. The metal core 15 is formed in a substantially L-shaped cross-section by press working from a steel plate having rust-preventing ability such as an austenitic stainless steel plate (such as SUS304 of JIS standard) or a rust-proof cold-rolled steel plate. . The seal member 16 is made of synthetic rubber such as NBR, and has a side lip 16a extending obliquely outward in the radial direction, a grease slip 16b and a middle lip 16c formed in a forked shape.

  On the other hand, the slinger 14 is formed into a substantially L-shaped cross-section by press working from a steel plate having rust-preventive properties such as an austenitic stainless steel plate or a rust-proofed cold-rolled steel plate, and is pressed into the outer diameter of the inner ring 5. It has a cylindrical portion 14a and an upright portion 14b extending radially outward from the cylindrical portion 14a. Then, the side lip 16a of the seal member 16 is slid with the outer side surface of the standing plate portion 14b with a predetermined axial squeeze, and the grease slip 16b and the intermediate lip 16c are brought into contact with the cylindrical portion 14a in a predetermined radial direction. It is slid in contact via a shimeshiro. Further, the upright plate portion 14b of the slinger 14 is opposed to the seal plate 13 via a slight radial clearance to form a labyrinth seal.

  Here, a chamfered portion 18 is formed at the inner diameter end on the inner side of the inner ring 5, that is, at the inner diameter end on the large end face (rear end face) 17 side. As shown in FIG. 2B, the chamfered portion 18 has an arc surface 19 having a predetermined radius of curvature r1 and gradually inclines radially outward from a tangent line of the arc surface 19 toward the inner side. And a conical concave inclined surface 20 having a predetermined inclination angle α1. The caulked portion 7 is formed so as to include the chamfered portion 18 and to be in close contact with the large end surface 17.

  In the present embodiment, the radius of curvature r1 of the arc surface 19 of the chamfered portion 18 is set to 1.5 mm, the axial dimension L1 of the chamfered portion 18 is set to 1.0 mm, and the radial dimension L2 is set to 2.0 mm. ing. The inclination angle α1 of the inclined surface 20 of the chamfered portion 18 is set to 20 degrees or less. Thereby, the intersection angle α2 between the large end face 17 of the inner ring 5 and the inclined surface 20 becomes as large as 160 degrees or more, and in the manufacturing process, when the inner rings 5 or the inner ring 5 collide with an external interference object such as a transport facility, Occurrence of a flaw due to the edge of this portion can be suppressed. Further, the inner ring 5 can be prevented from being elastically deformed radially outward during the crimping process, so that the hoop stress of the inner ring 5 can be reduced, and the hoop stress is generated in the inner ring 5 with the crimping process. In addition, it is possible to provide a wheel bearing device in which the occurrence of delayed destruction due to a dent is suppressed and durability is improved.

  The chamfered portion 18 of the inner race 5 is formed by turning, and the small end face 5c and the large end face 17 are formed by grinding after heat treatment. The intersection between the large end surface 17 and the inclined surface 20 of the chamfered portion 18 is smoothly rounded by cutting or paper wrapping by this grinding. Thus, it is possible to prevent the occurrence of burrs and to suppress the occurrence of nicks due to edges.

  It should be noted that this type of wheel bearing device is used in a state of being exposed to a severe external environment on a road surface, and is often subjected to muddy water. Further, in coastal areas, salt water is sprinkled, and in cold regions, an anti-freezing agent may be sprayed, and muddy water containing salt in the anti-freezing agent is sprinkled. In particular, since the inner ring 5 is exposed as it is as a steel material base, there is a possibility that corrosion due to salt damage may occur if salt mud is sprayed. In such a situation, if the corrosion of this portion progresses, diffusible hydrogen existing in the environment penetrates into the structure of the inner ring 5 to cause hydrogen embrittlement, and delayed fracture occurs in which metal grain boundaries are broken. It is not preferable because it may be caused.

  In the wheel bearing device according to the present invention, since the caulking portion 7 is formed in a state in which it includes the chamfered portion 18 and is in close contact with the large end surface 17, the chamfered portion 18 of the inner ring 5 is not exposed. In addition to preventing rainwater and dust from entering the joint surface between the chamfered portion 18 and the caulked portion 7 of the inner ring 5, the chamfered portion 18 of the inner ring 5 where hoop stress is generated is not only damaged by bruises but also corroded by salt damage. Thus, it is possible to prevent the occurrence of delayed destruction.

  FIG. 3 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention, and FIG. 4 is a longitudinal sectional view showing a modification of the wheel bearing device of FIG. This embodiment is basically different from the above-described first embodiment (FIG. 1) only in the configuration of the hub ring and the bearing portion, and other components having the same parts and the same functions as those of the above-described embodiment. , Parts are denoted by the same reference numerals, and detailed description is omitted.

  The wheel bearing device shown in FIG. 3 has a second-generation structure on the drive wheel side, and includes a hub wheel 21 and a wheel bearing 22 mounted on the hub wheel 21. The hub wheel 21 has a wheel mounting flange 6 at an end on the outer side, a small-diameter stepped portion 21b extending in the axial direction from the wheel mounting flange 6 via a shoulder 21a is formed on the outer periphery, and torque is transmitted on the inner periphery. Serrations (or splines) 21c are formed. Then, the wheel bearing 22 is press-fitted into the small-diameter step portion 21b via a predetermined shimeshiro, and the bearing preload is applied by the caulking portion 7 formed by plastically deforming the end of the small-diameter step portion 21b in the axial direction. It is fixed to. The hub wheel 21 is made of medium-high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and has a surface hardness in the range of 50 to 64 HRC by induction hardening from the shoulder 21a to the small diameter step 21b. Has been subjected to a curing treatment.

  The wheel bearing 22 has a body mounting flange 2b integrally formed on the outer periphery, an outer member 2 integrally formed with multiple rows of outer rolling surfaces 2a, 2a formed on the inner circumference, and a double row of outer races formed on the outer circumference. Inner races 23, 5 formed with inner rolling surfaces 5a opposed to running surfaces 2a, 2a, respectively, and double-row rolling elements rotatably accommodated between both rolling surfaces via retainers 8, 8. 3 and 3 and seals 10 and 10 attached to openings of an annular space formed between the outer member 2 and the inner rings 23 and 5. The inner ring 23 is made of a high carbon chromium bearing steel such as SUJ2, and is hardened to 58 to 64 HRC up to the core by hardening.

  In the present embodiment, of the pair of inner races 23, 5, the chamfered portion 23a on the large end face side of the inner race 23 on the outer side is formed larger than the chamfered portion 18 on the inner race 5 on the inner side. Thereby, the chamfer of the corner 21d between the shoulder 21a and the small diameter step 21b of the hub wheel 21 can be set large, and stress concentration can be reduced even when a large moment load is applied to the wheel mounting flange 6. As a result, the strength and durability of the hub wheel 21 can be improved.

  Here, similarly to the above-described embodiment, the chamfered portion 18 of the inner ring 5 on the inner side is formed by an arc surface 19 and an inclined surface 20 which is gradually inclined radially outward from a tangent to the arc surface 18 toward the inner side. The pair of inner rings 23 and 5 are fixed to the hub wheel 21 in a state where the pair of inner rings 23 and 5 are sandwiched between the caulking portion 7 and the shoulder 21a of the hub wheel 21. Thereby, it is possible to suppress the inner ring 5 on the inner side from being elastically deformed radially outward due to the rocking and crimping, to reduce the hoop stress of the inner ring 5, and to add the hoop to the inner ring 5 with the crimping process. Even if stress is generated, it is possible to suppress the occurrence of delayed destruction due to a dent and improve durability.

  The bearing device for a wheel shown in FIG. 4 is a modified example of the bearing device for a wheel (FIG. 3) described above, and basically differs only in a part of the configuration of the bearing for a wheel. In addition, the same parts and parts having the same functions as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

  This wheel bearing device has a first-generation structure on the driving wheel side, and includes a hub wheel 21 and a wheel bearing 24 mounted on the hub wheel 21. The wheel bearing 24 includes an outer member 25 having a double row of outer rolling surfaces 2a, 2a integrally formed on the inner periphery, and an inner rolling surface facing the double row of outer rolling surfaces 2a, 2a on the outer periphery. Inner races 23, 5 each formed with 5a; double-row rolling elements 3, 3 rotatably accommodated between both rolling surfaces via retainers 8, 8; outer member 25 and inner race 23 5 and seals 10 and 10 attached to the opening of the annular space formed between the seals 10 and 5.

  The outer member 25 has no vehicle body mounting flange on the outer periphery and is directly fitted to a knuckle (not shown). The outer member 25 is formed of a high carbon chromium steel such as SUJ2, and is hardened to a core portion in the range of 58 to 64 HRC by subbing quenching.

  Here, also in the present embodiment, similarly to the above-described embodiment, the chamfered portion 18 of the inner ring 5 on the inner side is gradually inclined toward the inner side radially outward from the arc surface 19 and the tangent to the arc surface 19. It includes a chamfered portion 18 of the inner race 5, and is rocked and swaged in a state of being in close contact with the large end surface 17. Thereby, it is possible to suppress the inner ring 5 on the inner side from being elastically deformed radially outward due to the rocking and crimping, to reduce the hoop stress of the inner ring 5, and to add the hoop to the inner ring 5 with the crimping process. Even if stress is generated, it is possible to suppress the occurrence of delayed destruction due to a dent and improve durability.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to these embodiments at all, but is merely an example, and may be variously modified without departing from the gist of the present invention. It goes without saying that the scope of the present invention is indicated by the description of the claims, and furthermore, the equivalent meaning described in the claims, and all the changes within the scope are described. Including.

  The wheel bearing device according to the present invention is a first generation in which an inner ring is press-fitted into a small-diameter step portion of a hub wheel, and the inner ring is axially fixed by a caulking portion formed by plastically deforming the end of the small-diameter step portion. The present invention can be applied to a third-generation self-retained wheel bearing device.

Reference Signs List 1 inner member 2, 25 outer member 2a outer rolling surface 2b body mounting flange 3 rolling element 4, 21 hub wheel 4a, 5a inner rolling surface 4b, 21b small-diameter step portion 4c, 21a shoulder portion 5, 23 inner ring 5c Small end face 6 Wheel mounting flange 6a Hub bolt 6b Inner base 7 of wheel mounting flange Caulking section 8 Cage 9, 10 Seal 11, 15 Core metal 12, 16 Seal member 12a, 12b, 16a Side lip 12c, 16b Grease slip Reference Signs List 13 seal plate 14 slinger 14a cylindrical portion 14b upright plate portion 16c intermediate lip 17 large end surface 18, 23a of inner ring chamfered portion 19 arc surface 20 inclined surface 21c serration 21d corner portion 22, 24 wheel bearing 51 inner member 52 outer member 52a Outer rolling surface 52b Body mounting flange 53 Ball 54 Hub wheel 54a, 55a Inner rolling surface 54b Small Steps 55, 60 Inner ring 55b, 61 Large end face of inner ring 56 Wheel mounting flange 56a Hub bolts 57, 63 Caulking section 58 Cage 59, 62 Inclined surface L1 Axial dimension L2 of chamfered part Radial dimension r1 of chamfered part Arc surface The radius of curvature α1 The inclination angle α2 of the inclined surface The intersection angle θ1, θ3 between the large end surface of the inner ring and the inclined surface The inclination angle θ2, θ4 of the inclined surface The intersection angle between the large end surface of the inner ring and the inclined surface

Claims (2)

An outer member in which a double row of outer rolling surfaces are integrally formed on the inner periphery,
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, a small-diameter step extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step of the hub wheel. An inner member having a double row inner rolling surface formed on the outer periphery thereof, the double row inner rolling surface being opposed to the double row outer rolling surface;
A wheel bearing device comprising: a double-row rolling element rotatably accommodated between the double-row outer rolling surface and the double-row inner rolling surface;
The inner ring is axially fixed by a caulking portion formed by plastically deforming the end of the small-diameter step portion of the hub wheel radially outward,
A chamfered portion is formed at an inner diameter end on the large end surface side of the inner ring, and the chamfered portion is constituted by an arc surface and an inclined surface gradually inclined toward the inner side radially outward from a tangent line of the arc surface. the extension and the angle a of the large end face of the inner ring of the inclined surface of the chamfered portion is set below 20 degrees, the caulking portion includes the inner ring of the chamfer, in close contact with the large end face of the inner ring A bearing device for a wheel, wherein the bearing device is formed in a cut state.   The wheel bearing device according to claim 1, wherein the intersection between the large end surface of the inner ring and the inclined surface of the chamfered portion is smoothly rounded.

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