JP4998979B2 - Wheel bearing device - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly to a wheel bearing device that achieves light weight and compactness and increases rigidity to extend the life of a bearing. .

  2. Description of the Related Art 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 rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. As the wheel bearing device, 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. On the other hand, double row tapered roller bearings are used in vehicles such as off-road cars and trucks that have a heavy vehicle body weight.

  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. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. 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 speed universal joint.

  In such a wheel bearing device, conventionally, both rows of bearings have the same specification, so that they have sufficient rigidity when stationary, but the optimum rigidity is not always obtained when the vehicle turns. That is, the position of the vehicle weight when stationary is determined so that it acts on the approximate center of the double row rolling bearing, but when turning, the opposite side of the turning direction (when turning right, the vehicle A large radial load or axial load is applied to the left axle. Therefore, at the time of turning, it is effective to increase the rigidity of the outer bearing row rather than the inner bearing row. Then, what is shown in FIG. 4 is known as a wheel bearing apparatus which improved the rigidity at the time of turning, without enlarging an apparatus.

  This wheel bearing device 50 has a vehicle body mounting flange 51c integrally attached to a knuckle (not shown) on the outer periphery, and an outer side in which double row outer rolling surfaces 51a and 51b are formed on the inner periphery. A member 51 and a wheel mounting flange 53 for mounting a wheel (not shown) at one end are integrally formed, and one inner rolling surface 52a facing the double row outer rolling surfaces 51a and 51b on the outer periphery. The hub wheel 52 having a small-diameter step portion 52b extending in the axial direction from the inner rolling surface 52a and the small-diameter step portion 52b of the hub wheel 52 are externally fitted to the double-row outer rolling surfaces 51a and 51b. An inner member 55 composed of an inner ring 54 formed with the other inner rolling surface 54a facing each other, double rows of balls 56, 57 accommodated between both rolling surfaces, and these double rows of balls 56, 57 A retainer 58 for freely rolling It is composed of a double row angular contact ball bearing with a 9.

  The inner ring 54 is fixed in the axial direction by a caulking portion 52c formed by plastically deforming a small diameter step portion 52b of the hub wheel 52 radially outward. Seals 60 and 61 are attached to the opening of the annular space formed between the outer member 51 and the inner member 55, leakage of the lubricating grease sealed inside the bearing, and rainwater from the outside into the bearing. And dust are prevented from entering.

Here, the pitch circle diameter D1 of the outer side ball 56 is set larger than the pitch circle diameter D2 of the inner side ball 57. Along with this, the inner rolling surface 52a of the hub wheel 52 is expanded in diameter than the inner rolling surface 54a of the inner ring 54, and the outer rolling surface 51a on the outer side of the outer member 51 is also rolled on the inner side. The diameter is larger than that of the surface 51b. The outer side balls 56 are accommodated more than the inner side balls 57. In this way, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device 50 can be extended. it can.
JP 2004-108449 A

  In such a conventional wheel bearing device 50, the pitch circle diameter D1 of the outer ball 56 is set to be larger than the pitch circle diameter D2 of the inner ball 57, and accordingly, the inner rolling of the hub wheel 52 is performed. Since the diameter of the surface 52a is larger than that of the inner rolling surface 54a of the inner ring 54, the rigidity of the outer bearing row is improved, and the life of the wheel bearing device 50 can be extended. However, the rigidity of the inner side bearing row is insufficient with respect to the rigidity of the outer side bearing row, and the outer side of the hub wheel 52 is formed with a larger diameter. It was impossible to reduce the weight of the device.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wheel bearing device that solves the conflicting problems of light weight, compactness, and high rigidity of the device.

In order to achieve the object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle on the outer periphery, and a double row outer rolling surface is formed on the inner periphery. An outer member, and a wheel mounting flange for mounting a wheel at one end are integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and an axis from the inner rolling surface A hub wheel formed with a small-diameter step portion extending in the axial direction through the ring-shaped portion, and press-fitted into the small-diameter step portion of the hub wheel via a predetermined shimiro, and opposed to the outer rolling surface of the double row on the outer periphery An inner member formed of an inner ring on which the other inner rolling surface is formed, and a double row tapered roller accommodated in a freely rolling manner between both rolling surfaces of the inner member and the outer member, The inner ring is formed by a caulking portion formed by plastically deforming a small-diameter step portion of the hub wheel radially outward. In There wheel bearing device fixed axially, the pitch circle diameter of the conical inner side rollers at the cone roller portion of the double row is set smaller in diameter than the pitch circle diameter of the tapered rollers on the outer side, of the hub wheel A shaft-shaped portion extending in the axial direction from the groove bottom portion of the inner rolling surface to the small-diameter step portion is formed, and a chamfered portion is formed at the step portion between the shaft-shaped portion and the shoulder portion that abuts against the inner ring. And a mortar-shaped recess is formed at the outer end of the hub wheel, and the depth of the recess exceeds the groove bottom of the inner raceway surface of the hub wheel and near the chamfered portion. In addition, a large flange for guiding the tapered roller is not formed on the large diameter side of the inner raceway surface of the hub wheel, and this large collar is provided on the large diameter side of the outer raceway surface of the outer member. And the inner rolling surface from the inner side base of the wheel mounting flange Predetermined hardened layer by induction hardening over the vicinity of the crimping portion in the cylindrical portion via a shaft-like portion are formed continuously.

Thus, an outer member having a vehicle body mounting flange on the outer periphery, a hub wheel having a wheel mounting flange at one end, an inner member made of an inner ring press-fitted into the hub wheel, and the inner member and the outer member. A third generation structure having a double row tapered roller housed between the members, the inner ring being fixed in the axial direction by a caulking portion formed by plastically deforming a small diameter step portion of the hub ring radially outward. In the wheel bearing device, the pitch circle diameter of the inner side tapered rollers in the double row tapered rollers is set to be smaller than the pitch circle diameter of the outer side tapered rollers, and the smaller diameter from the groove bottom of the inner raceway surface of the hub ring. A shaft-like portion extending in the axial direction is formed over the step portion, and a chamfered portion is formed at the step portion between the shaft-like portion and the shoulder portion that is abutted against the inner ring, and the outer side of the hub wheel is formed. A mortar-shaped recess is formed at the end. Saga is a near chamfered portion beyond the groove bottom of the inner raceway surface of the wheel hub, not large rib is formed to guide the tapered rollers on the large diameter side of the inner raceway surface of the wheel hub, the large rib Is provided on the large-diameter side of the outer rolling surface of the outer member, and from the base on the inner side of the wheel mounting flange to the vicinity of the caulking portion in the small-diameter step portion via the inner rolling surface and the shaft-shaped portion. In other words, since the predetermined hardened layer is continuously formed by induction hardening, it is possible to provide a wheel bearing device that solves the conflicting problems of light weight, compactness, and high rigidity of the device.

Preferably, as in the invention described in claim 2, the thickness of the inner raceway surface of the hub wheel is set within a predetermined range and at least twice the effective hardened layer depth in the hardened layer. Thus, weight reduction can be achieved, and the hub ring can be prevented from cracking due to induction hardening.

  Further, as in the invention described in claim 3, the wall thickness t1 on the large diameter side of the inner raceway surface of the hub wheel is set to be thicker than the wall thickness t2 of the central portion, and the wall thicknesses t1 and t2 However, if the diameters d1 and d2 of these parts are set to be in the range of 0.2 to 0.3, weight reduction is achieved while ensuring the strength and rigidity of the hub wheel corresponding to the use conditions. can do.

  In addition, if the diameter of the inner side tapered roller is set smaller than the diameter of the outer side tapered roller as in the invention described in claim 4, the knuckle size can be reduced and the device can be made lighter and more compact. In addition, the basic load rating of each rolling element row can be increased.

  Further, as in the invention described in claim 5, the end portion of the small diameter step portion before caulking is formed as a hollow cylindrical portion, and a depth of 0.5 to 1.0 mm is formed on the outer peripheral surface of the cylindrical portion. Is formed on the inner side of the inner ring at a position corresponding to the large-diameter end of the inner raceway surface, and slightly extends from the large end surface beyond the chamfered portion of the inner ring. If the hardened layer is formed up to the annular groove, the inner ring fixing force can be secured while suppressing deformation of the inner ring due to caulking, and the workability of the cylindrical portion of the small diameter step portion can be improved. It is possible to improve and prevent the occurrence of cracks and the like due to plastic deformation, and to suppress deformation of the hub wheel due to caulking.

The wheel bearing device according to the present invention has an outer member integrally formed with a vehicle body mounting flange to be attached to the knuckle on the outer periphery, a double row outer rolling surface formed on the inner periphery, and a wheel at one end. A wheel mounting flange for mounting the inner ring, and one outer rolling surface facing the outer rolling surface of the double row on the outer periphery, and extending in the axial direction from the inner rolling surface via the shaft portion. A hub wheel having a small-diameter step portion, and a small-diameter step portion of the hub wheel are press-fitted through a predetermined scissors, and the other inner rolling surface facing the double-row outer rolling surface is formed on the outer periphery. An inner member formed of an inner ring, and a double row tapered roller that is rotatably accommodated between the rolling surfaces of the inner member and the outer member. Wheel in which the inner ring is fixed in the axial direction by a caulking portion formed by plastic deformation outward in the direction In the bearing device, the pitch circle diameter of the tapered rollers on the inner side of the conical roller portion of the double row is set smaller in diameter than the pitch circle diameter of the tapered rollers on the outer side, wherein the groove bottom of the inner raceway surface of the hub wheel A shaft-shaped portion extending in the axial direction is formed over the small-diameter step portion, and a chamfered portion is formed at a step portion between the shaft-shaped portion and a shoulder portion that abuts against the inner ring, and the hub wheel A mortar-shaped recess is formed at the outer end, and the depth of the recess exceeds the groove bottom of the inner rolling surface of the hub wheel and is near the chamfered portion. A large collar for guiding the tapered roller is not formed on the large diameter side of the surface, and this large collar is provided on the large diameter side of the outer rolling surface of the outer member, and the wheel mounting flange The small diameter step from the base on the inner side through the inner rolling surface and the shaft portion Since the predetermined hardened layer is continuously formed by induction quenching in the vicinity of the caulking portion in the above, a wheel bearing device that solves the conflicting problems of light weight, compactness and high rigidity of the device is provided. Can be provided.

A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface via the shaft portion, And an inner member formed of an inner ring that is press-fitted into a small-diameter step portion of the hub ring through a predetermined shimoshiro and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, A double row tapered roller that is rotatably accommodated between both rolling surfaces of the inner member and the outer member, and is formed by plastically deforming the small-diameter step portion of the hub wheel radially outward. In the wheel bearing device in which the inner ring is fixed in the axial direction by a caulking portion, the double row A large flange that guides the tapered roller to the larger diameter side of the inner raceway surface of the hub wheel, in which the pitch circle diameter of the tapered roller on the inner side of the tapered roller is set smaller than the pitch circle diameter of the tapered roller on the outer side. The large flange is provided on the large diameter side of the outer rolling surface of the outer member, and extends from the groove bottom of the inner rolling surface of the hub wheel to the small diameter step portion. A shaft-shaped portion extending in the axial direction is formed, a chamfered portion is formed at a step portion between the shaft-shaped portion and a shoulder portion that is abutted against the inner ring, and an outer side end portion of the hub wheel is formed. A mortar-shaped recess is formed, and the depth of the recess exceeds the groove bottom of the inner raceway surface of the hub wheel and is in the vicinity of the chamfered portion so that the thickness of the inner raceway surface is within a predetermined range. Set from the inner side base of the wheel mounting flange through the inner rolling surface and the shaft-like part. Predetermined hardened layer is continuously formed by high frequency induction quenching over the vicinity of the crimping portion in the cylindrical portion Te.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 is a longitudinal sectional view showing a single hub wheel of FIG. 1, and FIG. 3 (a) is a main portion of FIG. An enlarged view and (b) are the principal part enlarged views before the caulking of (a). In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  This wheel bearing device is for a driven wheel called a third generation, and includes an inner member 1, an outer member 2, and a double row tapered roller 3 accommodated between the members 1 and 2 so as to roll freely. 4 is provided. The inner member 1 includes a hub ring 5 and an inner ring 6 press-fitted into the hub ring 5 through a predetermined shimiro.

  The hub wheel 5 integrally has a wheel mounting flange 7 for mounting a wheel (not shown) at one end portion, one (outer side) tapered inner rolling surface 5a on the outer periphery, and this inner rolling. A small-diameter step portion 5b is formed through an axial portion 8 extending in the axial direction from the surface 5a. A large collar for guiding the tapered roller 3 is not formed on the large diameter side of the inner raceway surface 5a of the hub wheel 5, and a large collar 14 is provided on the outer member 2 described later. Further, a small flange for holding the tapered roller 3 is not formed on the small diameter side of the inner rolling surface 5a, and the inner rolling is smoothly performed from the base portion 7c on the inner side of the wheel mounting flange 7 formed in an arc shape. The running surface 5a continues, and an axial portion 8 is formed that extends straight from the small diameter side of the inner rolling surface 5a in the axial direction.

  Further, hub bolts 7a are planted on the wheel mounting flange 7 in a circumferentially equidistant 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) tapered inner rolling surface 6a on the outer periphery, a large collar 6b for guiding the tapered roller 4 to the large diameter side of the inner rolling surface 6a, and a small diameter side In addition, a small scissors 6c for preventing the tapered roller 4 from falling off is formed. The inner ring 6 is press-fitted into the small-diameter step portion 5b of the hub wheel 5 through a predetermined shimiro, and a predetermined bearing preload is applied by a caulking portion 9 formed by plastically deforming the end of the small-diameter step portion 5b. Is fixed in the axial direction. As a result, it is possible to provide a self-retaining structure that achieves light weight and compactness and that maintains the initially set preload for a long period of time.

  The outer member 2 integrally has a vehicle body mounting flange 2c to be attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and an outer member facing the inner rolling surface 5a of the hub wheel 5 on the inner periphery. A tapered outer rolling surface 2a on the side and an inner tapered outer rolling surface 2b facing the inner rolling surface 6a of the inner ring 6 are integrally formed. In the present embodiment, the outer member 2 is provided with a large collar 14 that guides the tapered roller 3 on the outer side. That is, a large collar 14 that abuts on the large end surface of the tapered roller 3 and guides the tapered roller 3 is integrally provided on the outer diameter side of the outer side outer rolling surface 2 a of the outer member 2. As a result, the stress concentration on the hub wheel 5 with respect to the load applied via the tapered roller 3 is alleviated, and even if a large moment load is applied to the wheel mounting flange 7, the hub ring 5 is not easily fatigued. -Durability can be ensured.

  The outer member 2 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the outer surface 2a, 2b of the large punch 14 and the double row has a surface hardness of 58 to 58 by induction hardening. Hardened to a range of 64 HRC. And double-row tapered rollers 3 and 4 are respectively accommodated between the rolling surfaces 2a, 5a and 2b and 6a via cages 10 and 11 so as to roll freely. Further, seals 12 and 13 are attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of grease sealed inside the bearing to the outside and rainwater from the outside. And dust are prevented from entering the bearing. The outer-side seal 12 includes three side lips that are in sliding contact with a base portion 7c described later, and the inner-side seal 13 is integrally joined with a magnetic encoder.

  In this embodiment, the pitch circle diameter PCDi of the inner side tapered roller 4 is set to be smaller than the pitch circle diameter PCDo of the outer side tapered roller 3, and the diameter of the inner side tapered roller 4 is the outer cone. It is set smaller than the diameter of the roller 3. Thereby, the outer diameter D of the inner side in the outer member 2 can be set to a small diameter. As described above, the tapered rollers 3 and 4 are used as the double row rolling elements, and the pitch circle diameters and the diameters of the outer side and the inner side tapered rollers 3 and 4 are made different, whereby the knuckle size can be reduced. It is possible to reduce the weight and size, increase the basic load rating of each rolling element row, and increase the rigidity of the rolling element row portion.

  Here, a chamfered portion 8b is formed at a step portion between the shaft-like portion 8 of the hub wheel 5 and the shoulder portion 8a against which the inner ring 6 is abutted. A mortar-shaped recess 15 is formed on the outer end of the hub wheel 5 by forging. The depth of the recess 15 is from the groove bottom portion of the inner rolling surface 5a to the vicinity of the chamfered portion 8b beyond the shaft-shaped portion 8, and the outer end portion of the hub wheel 5 is formed to have a substantially uniform thickness. ing.

  The hub wheel 5 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 5a, shaft A hardened layer 16 having a surface hardness in the range of 58 to 64 HRC is formed by induction hardening across the shape portion 8, the chamfered portion 8b, and the small diameter step portion 5b (shown by cross hatching in the figure). The caulking portion 9 is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 7, and the fretting resistance of the small-diameter step portion 5 b serving as the fitting portion of the inner ring 6 is improved, and caulking is performed. There is no generation of minute cracks or the like during processing, and the plastic processing of the crimped portion 9 can be performed smoothly. The inner ring 6 and the tapered rollers 3 and 4 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core portion by quenching.

  When a moment load is applied to the wheel mounting flange 7 during traveling of the vehicle, it is considered that the hub wheel 5 is deformed starting from the inner side rolling surface 5a on the outer side. Therefore, in the present embodiment, this inner side rolling surface 5a. We focused on the outer wall thickness. That is, as shown in FIG. 2, the thickness t1 on the large diameter side of the inner rolling surface 5a is formed thicker than the thickness t2 at the center of the inner rolling surface 5a. Further, as a result of obtaining the rigidity of the hub wheel 5 by FEM analysis, the relationship between the thicknesses t1 and t2 and the diameters d1 and d2 of the respective portions is 0.2 ≦ t1 / d1 ≦ 0.3 and 0 In the range of 2 ≦ t2 / d2 ≦ 0.3, the effective hardened layer depth in the hardened layer 16 is set to be twice or more. Note that when the large-diameter side wall thickness t1 and the central wall thickness t2 of the inner raceway surface 5a are less than 20% of the diameters d1 and d2 of the respective portions, the deformation becomes large and the desired rigidity cannot be obtained. On the other hand, even if the thickness exceeds 30%, the rigidity is not increased so much that it is not preferable because the weight is increased. Thereby, while preventing the cracking by induction hardening, weight reduction can be achieved, ensuring the intensity | strength and rigidity of the hub ring 5 corresponding to use conditions. Here, the effective hardened layer depth is set to a range of 2 to 5 mm (about 3.5 mm).

  Further, in the present embodiment, as shown in an enlarged view in FIG. 3A, a chamfered portion 6d having a curvature radius r1 is formed at the inner diameter end portion of the large end surface 6e of the inner ring 6. The radius of curvature r1 of the chamfered portion 6d is set to R1.0 to 2.5. Here, if r1 is set to be smaller than 1.0 mm, when a bending moment load is applied to the device during operation of the vehicle, stress concentration occurs at the root portion of the caulking portion 9 and damage such as micro cracks occurs. There is a fear. On the other hand, when r1 exceeds 2.5 mm, the inner ring 6 is pushed outward in the radial direction when the cylindrical portion 17 (shape before caulking indicated by a two-dot chain line in the figure) 17 is plastically deformed. An excessive hoop stress is generated in the outer diameter of 6, which is not preferable.

  On the other hand, as shown in (b), the bottom surface 17 a of the cylindrical portion 17 is formed to have a predetermined depth a from the large end surface 6 e of the inner ring 6. An annular groove (escape groove) 18 having a depth b is formed on the outer peripheral surface of the cylindrical portion 17. Then, arc surfaces 18a and 18b having curvature radii Ri and Ro are formed on both sides of the annular groove 18, respectively.

  In the caulking test conducted by the present applicant, when the depth a of the bottom portion 17a of the cylindrical portion 17 is in the range of 0 to 5 mm, the hoop stress generated at the outer diameter of the inner ring 6 decreases as the depth a increases. However, it was found that when a <5 mm, the effect is small and no significant stress reduction is observed. On the other hand, if the depth a exceeds 5 mm, the inner ring push-in amount is insufficient and a predetermined inner ring fixing force cannot be obtained, and the strength and rigidity of the hub ring 5 are reduced.

  The depth b of the annular groove 18 is set in the range of 0.5 to 1.0 mm, and the radius of curvature Ri of the inner circular surface 18a in the annular groove 18 is set in the range of R1 to 10. Yes. The curvature radius Ri is set to be larger than the curvature radius r1 of the chamfered portion 6d of the inner ring 6 and smaller than the curvature radius Ro of the outer arc surface 18b (r1 ≦ Ri ≦ Ro). However, if the depth b of the annular groove 18 is smaller than 0.5 mm, the effect is reduced, and if it exceeds 1.0 mm, the strength of the crimped portion 9 may be insufficient, which is not preferable. By forming such an annular groove 18 on the outer peripheral surface of the cylindrical portion 17, the cylindrical portion 17 is easily deformed during caulking, and deformation of the inner ring 6 can be suppressed. Therefore, the large collar 6b of the inner ring 6 is not tilted by the caulking process, and the contact state with the tapered roller 4 is not impaired, and a desired life can be ensured.

  Further, the large diameter end (height of the large flange 6b) of the inner raceway surface 6a in the inner ring 6 is formed 5 mm or more away from the large end surface 6e in the axial direction. The annular groove 18 is located on the inner side of the position corresponding to the large-diameter end of the inner rolling surface 6a and extends slightly beyond the chamfered portion 6d of the inner ring 6 from the large end surface 6e. As the width of the annular groove 18 increases, the hoop stress decreases. However, if the width of the annular groove 18 is excessively large, not only the inner ring pressing amount is insufficient and a predetermined inner ring fixing force cannot be obtained, but also the strength and rigidity of the hub ring 5 are decreased. It is not preferable. Since the hardened layer 16 formed on the outer periphery of the hub wheel 5 is formed up to the annular groove 18, the workability of the cylindrical portion 17 of the small diameter step portion 5b is improved, and the occurrence of cracks and the like due to plastic deformation is prevented. In addition, the deformation of the hub wheel 5 due to the caulking process can be suppressed.

  In the wheel bearing device having such a configuration, the outer end portion of the hub wheel 5 is formed to have a substantially uniform thickness, and the wall thicknesses t1 and t2 of the inner rolling surface 5a are set within a predetermined range. Since the hardened layer 16 by induction hardening is formed in a predetermined range on the outer periphery of the wheel 5, it is possible to provide a wheel bearing device that can simultaneously solve the conflicting problems of light weight, compactness and high rigidity of the device. .

  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 wheel bearing device according to the present invention can be applied to a third-generation wheel bearing device for a driven wheel in which an inner ring is fixed by a caulking portion.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a longitudinal cross-sectional view which shows the hub ring single-piece | unit of FIG. (A) is a principal part enlarged view of FIG. (B) is a principal part enlarged view before the caulking of (a). It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1 ... Inner member 2 ... Outer member 3, 4, ... ··························································· Hub Rings 5a, 6a ·········· Small diameter step 6 ······················ Inner ring 6b, 14 ··········· Large鍔 6c ……………………………………………………………………………………………………. ·········· Large end surface 7 of the inner ring ·············· Wheel mounting flange 7a ... 7b ... round hole 7c ... base 8 ...・ ・ Shaft 8a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder 8b ・ ・ ・ ・ ・ ・ Chamfer 9 ・ ・ ・ ・ ・ ・········································································································. ··················· 16 ············································································ Wheel Bearing Device 51 ... Outer member 51a ... Outer rolling surface 51b on the outer side ... .... Inner side outer rolling surface 51c ..... Body mounting flange 52 ························· Hub hub 52a, 54a ······ Inner rolling surface 52b 52c ··············································· Wheel mounting flange 54 .... Inner ring 55 ... Inner members 56, 57 ... Balls 58, 59 ... ············· Retainer 60, 61 ·························································· ············ Depth groove depth d1 ··········· Diameter d2 on the large diameter side of the inner rolling surface .... Diameter D1 at the center of the inner rolling surface ... Pitch circle diameter D2 of the ball ......... pitch circle diameter PCDi of the ball on the inner side ... Pitch circle diameter PCDo ............ Pitch circle diameter r1 of the tapered roller on the outer side ............ Curve radius Ri of the chamfered portion of the inner ring ..... Radius of curvature Ro of the inner side arc surface in the annular groove ..... Outer side arc surface of the annular groove Radius of curvature t1 ..... Thickness t2 on the inner diameter side of the inner rolling surface .......... inner rolling surface Thickness of the center of

Claims (5)

An outer member integrally having a vehicle body mounting flange to be attached to the knuckle on the outer periphery, and a double row outer rolling surface formed on the inner periphery;
It has a wheel mounting flange for mounting a wheel at one end, and has one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a shaft-shaped portion from the inner rolling surface via the shaft-shaped portion. A hub wheel formed with a small-diameter step portion extending in the axial direction, and the other inner rolling member that is press-fitted into the small-diameter step portion of the hub wheel via a predetermined shimiro and faces the outer rolling surface of the double row on the outer periphery. An inner member comprising an inner ring having a surface formed thereon;
A double row tapered roller accommodated in a freely rolling manner between the rolling surfaces of the inner member and the outer member,
In the wheel bearing device in which the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming a small-diameter step portion of the hub wheel radially outward,
The pitch circle diameter of the inner side tapered rollers in the double row tapered rollers is set to be smaller than the pitch circle diameter of the outer side tapered rollers, and from the groove bottom portion of the inner raceway surface of the hub ring to the smaller diameter step portion. A shaft-shaped portion extending in the axial direction is formed, and a chamfered portion is formed at a step portion between the shaft-shaped portion and a shoulder portion that abuts against the inner ring, and an end on the outer side of the hub wheel. A mortar-shaped recess is formed in the portion, and the depth of the recess is near the chamfered portion beyond the groove bottom of the inner rolling surface of the hub wheel, and the large diameter of the inner rolling surface of the hub wheel. A large flange for guiding the tapered roller is not formed on the side, and the large flange is provided on the large diameter side of the outer rolling surface of the outer member, and the base portion on the inner side of the wheel mounting flange From the inner rolling surface and the shaft-shaped portion, the caulking portion in the small-diameter step portion Wheel bearing apparatus characterized by a predetermined hardened layer is continuously formed by high frequency induction quenching over the neighborhood. 2. The wheel bearing device according to claim 1, wherein a thickness of an inner raceway surface of the hub wheel is set within a predetermined range and at least twice an effective hardened layer depth in the hardened layer.   The wall thickness t1 on the large diameter side on the inner raceway surface of the hub wheel is set to be thicker than the wall thickness t2 of the central portion, and the wall thicknesses t1 and t2 are set to 0. The wheel bearing device according to claim 2, wherein the wheel bearing device is set to be in a range of 2 to 0.3.   The wheel bearing device according to any one of claims 1 to 3, wherein a diameter of the inner side tapered roller in the double row tapered roller is set smaller than a diameter of the outer side tapered roller. The end of the small diameter step portion before caulking is formed as a hollow cylindrical portion, and an annular groove having a depth of 0.5 to 1.0 mm is formed on the outer peripheral surface of the cylindrical portion. The inner ring is located on the inner side from the position corresponding to the large-diameter end of the inner rolling surface, extends slightly from the large end surface beyond the chamfered portion of the inner ring, and the hardened layer is formed up to the annular groove. The wheel bearing device according to any one of claims 1 to 4.

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