JP2013035338A - Wheel bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel bearing device that is made light in weight and compact, reduced in the processing man-hour and is lowered the cost through simplification of the assembly work.SOLUTION: The pitch circle diameter of a rolling element 3 at the inner side is set in diameter larger than the pitch circle diameter of the rolling element 3 of the outer side, a serration 20 hardened by induction hardening is formed by rolling processing to a small diameter step 4b of the hub wheel 4, an inner wheel 5 is made of the medium and high carbon steel containing 0.40-0.80 wt.% of carbon, a prescribed hardened layer 19 with a surface hardness set within the range of 58-64 HRC by induction hardening is formed ranging from an outer diameter surface 5b in which the seal 10 of the inner side including the inside rolling surface 5a is pressed in to the small end surface 5c; a face spline 13 and an inner diameter surface 5d are remained at the material hardness after forging and fit and adhered to the serration 20 while cutting and processing, and the hub wheel 4 and the inner wheel 5 are press-cut connected together.

Description

  The present invention relates to a wheel bearing device for supporting a wheel of a vehicle such as an automobile, and more specifically, a drive wheel (a front wheel of an FF vehicle, FR) provided with a wheel bearing and a constant velocity universal joint and mounted on an independent suspension type suspension. The present invention relates to a wheel bearing device that rotatably supports a rear wheel of a car or an RR car and all wheels of a 4WD car) with respect to a suspension device.

  A power transmission device that transmits engine power of a vehicle such as an automobile to a wheel transmits power from the engine to the wheel, and also causes radial or axial displacement from the wheel that occurs when the vehicle bounces or turns when traveling on a rough road. For example, one end of the drive shaft interposed between the engine side and the drive wheel side is connected to the differential through a sliding type constant velocity universal joint, and the like. The end is connected to the drive wheel via a wheel bearing device including a fixed type constant velocity universal joint.

  Various types of wheel bearing devices have been proposed in the past, and for example, those shown in FIG. 5 are known. The wheel bearing device includes a hub wheel (hub wheel) 50, a double row angular ball bearing 51 as a rolling bearing, and a constant velocity joint 52.

  The constant velocity joint 52 includes an inner ring (joint inner ring) 54 and an outer ring (outer joint member) 55 integrally connected to one end of the drive shaft 53, and a plurality of constant velocity joints 52 disposed between the inner and outer rings 54, 55. And a retainer 57 that holds the plurality of balls 56.

  A side face spline 59 is also formed on the end surface of the side wall (shoulder) 58 of the outer ring 55 of the constant velocity joint 52. Further, a connecting bolt 60 for connecting the hub wheel 50 and the constant velocity joint 52 integrally is projected at the center of the side wall portion 58 of the outer ring 55 of the constant velocity joint 52.

  The connecting bolt 60 has a head portion 61 and a shaft portion 62 that are separate from the outer ring 55 of the constant velocity joint 52, while a through hole 63 penetrates the center portion of the side wall portion 58 of the outer ring 55 of the constant velocity joint 52. It is installed. Then, the shaft portion 62 of the connecting bolt 60 is inserted and inserted from the inside opening portion of the through hole 63 of the outer ring 55 of the constant velocity joint 52, and the shaft portion 62 is moved to a position where the lower surface of the head portion 61 comes into contact with the inner surface of the side wall portion 58. When the large-diameter portion 62a of the root portion is press-fitted, the shaft portion 62 of the connecting bolt 60 is protruded and fixed from the side wall portion 58 of the outer ring 55 of the constant velocity joint 52. A male screw part 64 is formed at the tip of the shaft part 62 of the connecting bolt 60, and a tightening nut 65 is screwed to the male screw part 64.

  The hub wheel 50 integrally includes a cylindrical hub shaft 66 and a flange 67 formed on the outer peripheral surface near one end of the hub shaft 66. A plurality of hub bolts 68 for attaching a wheel (not shown) with a brake rotor (not shown) interposed therebetween are fixed to the flange 67 at a predetermined pitch and press-fitted. A double-row angular ball bearing 51 including an outer ring 69, an inner ring 70, a plurality of balls 71, and a cage 72 is assembled to the outer peripheral surface of the hub shaft 66.

  The hub shaft 66 has a raceway surface 66a corresponding to one raceway surface 69a of the outer ring 69 and a small-diameter shaft portion 73 formed on the outer periphery, and a raceway surface 70a corresponding to the other raceway surface 69a of the outer ring 69 is formed on the outer periphery. An inner ring 70 is fitted.

  On the outer peripheral surface of the small-diameter shaft portion 73 of the hub shaft 66 and the inner peripheral surface of the inner ring 70, external tooth splines 74 and internal tooth splines 75 that mesh with each other are formed. A side face spline 76 that meshes with the side face spline 59 on the end face of the side wall 58 of the outer ring 55 of the constant velocity joint 52 is formed on the end face of the inner ring 70. The hub wheel 50 and the constant velocity joint 52 are integrally connected so as to transmit torque.

  That is, the outer ring spline 74 on the outer peripheral surface of the small-diameter shaft portion 73 of the hub shaft 66 and the internal spline 75 on the inner peripheral surface of the inner ring 70 are meshed with each other to transmit the torque of the inner ring 70 to the small-diameter shaft portion 73 of the hub shaft 66. Fit as possible. Here, first, the shaft portion 62 of the connecting bolt 60 protruding from the end surface of the side wall portion 58 of the outer ring 55 of the constant velocity joint 52 is connected to one end side (the vehicle width direction center side) of the inner hole 77 of the hub shaft 66 of the hub wheel 50. ) To the other end side (the vehicle width direction outer side).

  Thereafter, the male screw part 64 at the tip of the shaft part 62 of the connecting bolt 60 is engaged with the side face spline 76 of the inner ring 70 of the hub shaft 66 and the side face spline 59 of the end face of the side wall part 58 of the outer ring 55 of the constant velocity joint 52. In a state in which is protruded to the other end side of the inner hole 77 of the hub shaft 66, the fastening nut 65 is fastened to the male screw portion 64.

  Therefore, the torque of the drive shaft 53 during traveling of the vehicle is sequentially transmitted to the inner ring 54, the plurality of balls 56, and the outer ring 55 of the constant velocity joint 52, and the outer ring 55 is rotated in the same direction as the drive shaft 53. The torque transmitted to the constant velocity joint 52 is transmitted to the inner ring 70 by meshing between the side face spline 59 of the outer ring 55 of the equivalent speed joint 52 and the side face spline 76 of the inner ring 70 on the hub wheel 50 side. Then, it is transmitted to the hub wheel 50 by meshing between the internal spline 75 of the inner ring 70 and the external spline 74 of the hub shaft 66, and the wheel is driven to rotate.

  By forming the side face spline 76 and the internal spline 75 on the end surface of the inner ring 70 on the hub wheel 50 side, the caulking portion at the end of the hub shaft of the conventional hub wheel is eliminated, and the hub shaft 66 of the hub wheel 50 is eliminated. And the outer ring 55 of the constant velocity joint 52 can be transmitted with good torque. In addition, unlike the conventional case, the wheel support device can be shortened in shaft length by eliminating the caulking portion at the end of the hub shaft, thereby reducing the weight. Further, the side face spline 76 can be easily formed on the end face of the single-piece inner ring 70 constituting the angular ball bearing 20 as the rolling bearing on the hub wheel 10 side, and the internal spline 75 can be easily formed on the inner peripheral surface by forging or the like. it can. Furthermore, after each spline 75, 76 is formed, quality assurance inspection can be easily performed with the inner ring 70 as a single item, which is also effective in reducing costs (for example, see Patent Document 1).

JP 2009-78676 A

  However, in such a conventional wheel bearing device 50, a plurality of splines on the small diameter shaft portion 73 and the inner ring 70 of the hub shaft 66 constituting the double row angular ball bearing 51, that is, external teeth on the outer peripheral surface of the small diameter shaft portion 73. Since it is necessary to form the spline 74, the side face spline 76 on the end surface of the inner ring 70, and the inner spline 75 on the inner diameter surface of the inner ring 70, it is possible to increase the number of forging steps and the accuracy of the inner ring 70 such as misalignment. There was a problem.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device that is light and compact, reduces the number of processing steps, simplifies assembly work, and reduces costs. It is an object.

  In order to achieve such an object, the invention described in claim 1 of the present invention has a vehicle body mounting flange integrally attached to the vehicle body on the outer periphery, and a double row outer rolling surface is integrally formed on the inner periphery. The outer member, and a wheel mounting flange for mounting the wheel at one end of the outer member, and one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and the inner rolling surface A hub ring formed with a cylindrical small-diameter step portion extending in an axial direction from the inner ring surface, and the other inner rolling surface that is press-fitted into the small-diameter step portion of the hub ring and that faces the outer rolling surface of the double row on the outer periphery. An inner member formed of an inner ring formed, a double row rolling element that is rotatably accommodated between both rolling surfaces of the inner member and the outer member, the outer member, and the inner member; And seals mounted on both side openings of the annular space formed between the inner ring and the large end surface of the inner ring. In the wheel bearing device in which the spline is formed, the pitch circle diameter of the inner side rolling elements of the double row rolling elements is set larger than the pitch circle diameter of the outer side rolling elements, and the hub wheel A serration that is hardened by induction hardening is formed on the small diameter step portion of the inner ring, and the inner peripheral surface of the inner ring is unquenched, and the hub ring and the inner ring are pressed together by being closely fitted while cutting into the serration. Cut and joined.

  In this way, in the wheel bearing device in which the inner ring is press-fitted into the small-diameter step portion of the hub ring and the face spline is formed on the large end surface of the inner ring, the pitch circle diameter of the inner-side rolling element among the double-row rolling elements Is set to be larger than the pitch circle diameter of the outer rolling element, serrations hardened by induction hardening are formed on the small diameter step portion of the hub wheel, and the inner peripheral surface of the inner ring is unquenched, resulting in serration. To provide a wheel bearing device that reduces the number of processing steps, simplifies assembly work, and lowers costs because the hub ring and inner ring are press-cut joined together by cutting and fitting closely together. In addition, since the pitch circle diameter of the inner-side rolling element is set larger than the pitch circle diameter of the outer-side rolling element, the inner ring can be made thicker and the press cutter can be made thicker. Suppressing the inner ring of the deformation at the time of bonding, it is possible to prevent the roundness of the inner raceway surface that collapse.

  Preferably, as in the invention described in claim 2, the inner ring is made of medium to high carbon steel containing carbon of 0.40 to 0.80 wt%, and the inner side seal including the inner rolling surface is press-fitted. A predetermined hardened layer is formed in the range of 58 to 64 HRC by induction hardening from the outer diameter surface to the small end surface, and the face spline and the inner diameter surface are kept in the material hardness after forging. If so, a desired driving force can be transmitted, and loosening of the coupling portion between the hub wheel and the inner ring can be prevented over a long period of time.

  Further, as in the third aspect of the invention, if the face spline is formed by plastic working, the cost can be reduced.

  Further, as in the invention described in claim 4, if the serrations of the small-diameter step portion are formed by rolling, cost reduction can be achieved.

  Further, as in the invention according to claim 5, the inner diameter of the inner ring is set to be smaller than the outer diameter of the serration of the small diameter step portion and larger than the root diameter of the serration, If the tip of the serration of the small diameter step portion is formed at the edge, the serration can be easily fitted to the inner diameter surface of the inner ring while cutting and the cut residue generated during press-cut joining is reduced. And can be discharged to the inner side without accumulating between the inner rings.

  Further, as in the invention described in claim 6, the hub wheel is made of medium to high carbon steel containing carbon of 0.40 to 0.80 wt%, and includes the inner rolling surface and the inner side of the wheel mounting flange. If the surface hardness is set to a range of 50 to 64 HRC by induction hardening from the base part of the steel to the small diameter step part, it can be easily press-cut joined, and the coupling part of the hub ring and the inner ring is loosened over a long period of time. Can be reliably prevented.

  Further, as in the invention according to claim 7, if the bottom of the face spline is formed on an arc surface having a predetermined radius of curvature, and the pressure angle is set in a range of 20 to 30 °, It is possible to relieve the stress at the bottom of the tooth generated when driving torque is applied and to achieve both torque transmission efficiency and plastic workability.

  The wheel bearing device according to the present invention has an outer member integrally formed with a vehicle body mounting flange for mounting to the vehicle body on the outer periphery, and an outer member formed integrally with a double row outer rolling surface on the inner periphery, and one end portion. A wheel mounting flange for mounting the wheel integrally on one side, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small cylindrical diameter extending in the axial direction from the inner rolling surface An inner member comprising a hub ring formed with a stepped portion and an inner ring press-fitted into a small-diameter stepped portion of the hub ring and formed with the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery. A double row rolling element that is slidably accommodated between both rolling surfaces of the inner member and the outer member, and an annular space formed between the outer member and the inner member. And a face spline formed on the large end face of the inner ring. In the wheel bearing device, a pitch circle diameter of the inner side rolling elements of the double row rolling elements is set to be larger than a pitch circle diameter of the outer side rolling elements, and a high frequency is provided in the small diameter step portion of the hub wheel. Since the serration cured by quenching is formed, the inner peripheral surface of the inner ring is unquenched, and the hub ring and the inner ring are integrally press-cut joined by cutting and fitting into the serration while cutting. It is possible to provide a wheel bearing device that reduces the number of processing steps, simplifies the assembly work, and reduces the cost, and the pitch circle diameter of the inner rolling element is equal to the pitch circle diameter of the outer rolling element. The diameter of the inner ring can be increased, the inner ring can be made thicker, the inner ring can be prevented from being deformed during press-cut joining, and the roundness of the inner raceway can be prevented from collapsing. That.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is explanatory drawing which shows the hardened layer pattern of the hub ring of FIG. 1, and an inner ring | wheel. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a fragmentary sectional view along the IV-IV line which shows the face spline part of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

  An outer member integrally having a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for mounting a wheel on one end A hub wheel formed integrally with one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a cylindrical small diameter step portion extending in an axial direction from the inner rolling surface; and An inner member comprising an inner ring press-fitted into a small-diameter step portion of the hub wheel and having the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and the inner member and the outer member A double row rolling element accommodated between both rolling surfaces of the member, and a seal attached to both side openings of an annular space formed between the outer member and the inner member; A wheel bearing device in which a face spline is formed on a large end surface of the inner ring. Among the rolling elements, the pitch circle diameter of the inner-side rolling element is set to be larger than the pitch circle diameter of the outer-side rolling element, and serrations hardened by induction hardening are rolled into the small-diameter step portion of the hub ring. The inner ring is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon, and is formed by processing, from the outer diameter surface into which the inner side seal including the inner rolling surface is press-fitted to a small end surface. Then, a predetermined hardened layer is formed in the range of 58 to 64 HRC by induction hardening, and the face spline and the inner diameter surface remain as the material hardness after forging, and adhere to the serration while cutting. The hub ring and the inner ring are integrally press-cut joined.

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 according to the present invention, FIG. 2 is an explanatory view showing a hardened layer pattern of a hub wheel and an inner ring of FIG. 1, and FIG. FIG. 4 is a partial cross-sectional view taken along line IV-IV showing the face spline portion of FIG. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing device has a third generation structure on the drive wheel side, and is a double row rolling element (ball) accommodated between the inner member 1 and the outer member 2 and between the members 1 and 2 so as to roll freely. 3 and 3. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at an end portion on the outer side, and a bolt for fixing a hub bolt to a circumferentially equidistant position of the wheel mounting flange 6. A hole 6a is formed. Further, one (outer side) arcuate inner rolling surface 4a and a cylindrical small-diameter step portion 4b extending in the axial direction from the inner rolling surface 4a are formed on the outer periphery of the hub wheel 4. The inner ring 5 is formed with the other (inner side) arcuate inner rolling surface 5a on the outer periphery, and is press-fitted into the small-diameter step portion 4b of the hub ring 4 through a predetermined squeeze.

  The hub wheel 4 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and as shown in FIG. 2, the seal land of the seal 9 described later, including the inner side rolling surface 4a on the outer side. The surface hardness is set in the range of 50 to 64 HRC by induction hardening from the base 6b on the inner side of the wheel mounting flange 6 serving as a portion to the small diameter step 4b (indicated by cross-hatching in the figure).

  Moreover, the rolling element 3 consists of high carbon chromium bearing steel, such as SUJ2, and is hardened in the range of 60-64 HRC to the core part by the quenching quenching. In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling element 3 was illustrated here, it is not restricted to this, The double row cone which uses the tapered roller for the rolling element 3 It may be composed of roller bearings.

  The outer member 2 integrally has a vehicle body mounting flange 2c for mounting to a knuckle (not shown) on the outer periphery, and has an arc shape facing the inner rolling surfaces 4a and 5a of the inner member 1 on the inner periphery. Double row outer rolling surfaces 2a, 2b are integrally formed. The double row rolling elements 3 and 3 are accommodated between the rolling surfaces 2a, 4a and 2b and 5a, and the double row rolling elements 3 and 3 are held by the cages 7 and 8 so as to freely roll. ing. Further, seals 9 and 10 are attached to the opening portion of the annular space formed between the outer member 2 and the inner member 1, and leakage of lubricating grease sealed inside the bearing and rainwater and dust from the outside. Etc. are prevented from entering the inside of the bearing.

  The outer member 2 is formed of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, as in the case of the hub wheel 4, and at least the double row outer raceway surfaces 2a and 2b are surfaced by induction hardening. Hardening is performed in the range of 58 to 64 HRC.

  In this embodiment, the pitch circle diameter PCDi of the inner side rolling elements 3 of the double row rolling elements 3 and 3 is set larger than the pitch circle diameter PCDo of the outer side rolling elements 3. The size of the double-row rolling elements 3 and 3 is the same, but the number of inner-side rolling elements 3 is set to be larger than the number of inner-side rolling elements 3 due to the difference in pitch circle diameters PCDo and PCDi. Has been.

  Thus, the pitch circle diameter PCDi of the inner side rolling element 3 is set to be larger than the pitch circle diameter PCDo of the outer side rolling element 3, and the number of inner side rolling elements 3 is correspondingly increased on the outer side. Since the number of rolling elements 3 is set larger than the number of rolling elements 3, the bearing rigidity of the inner side portion can be increased compared to the outer side, and the life of the bearing can be extended.

  The outer-side seal 9 includes a core 11 that is press-fitted into the inner circumference of the outer-side end portion of the outer member 2 via a predetermined shimiro, and a seal member that is integrally joined to the core 11 by vulcanization adhesion It is comprised by the integral seal | sticker which consists of 12. The metal core 11 is formed from an austenitic stainless steel plate (JIS standard SUS304 type or the like) or a cold rolled steel plate (JIS standard SPCC type or the like) in a substantially L-shaped cross section by press working.

  On the other hand, the seal member 12 is made of a synthetic rubber such as NBR (acrylonitrile-butadiene rubber), is formed to be inclined outward in the radial direction, and is in sliding contact with a base portion 6a having a circular cross section in a predetermined axial direction. A side lip 12a, a dust lip 12b, and a grease lip 12c formed so as to be inclined toward the inner side of the bearing and slidably contacted with the base portion 6a via a predetermined radial shimoshiro.

  In addition to NBR, the material of the seal member 12 is excellent in heat resistance and chemical resistance, such as HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc., which have excellent heat resistance. Examples thereof include ACM (polyacrylic rubber), FKM (fluororubber), and silicon rubber.

  On the other hand, the seal 10 on the inner side is constituted by a so-called pack seal comprising a slinger 14 and an annular seal plate 15 arranged to face each other as shown in an enlarged view in FIG. The slinger 14 is formed into a substantially L-shaped cross section by pressing from a ferromagnetic steel plate, for example, a ferritic stainless steel plate (JIS standard SUS430 series, etc.) or a rust-proof cold rolled steel plate. The cylindrical portion 14a is press-fitted into the outer peripheral surface 5b of the inner ring 5, and the upright plate portion 14b extends radially outward from the cylindrical portion 14a.

  A magnetic encoder 16 in which a magnetic powder such as ferrite is mixed in an elastomer such as rubber is integrally vulcanized and bonded to the inner side surface of the standing plate portion 14b. The magnetic encoder 16 is magnetized with magnetic poles N and S alternately in the circumferential direction to constitute a rotary encoder for detecting the rotational speed of the wheel.

  On the other hand, the seal plate 15 includes a cored bar 17 fitted into the end of the outer member 2 and a seal member 18 integrally joined to the cored bar 17 by vulcanization adhesion. The metal core 17 is formed of an austenitic stainless steel plate or a cold-rolled steel plate that has been rust-proofed by a pressing process so that the cross-section is substantially L-shaped, and a cylindrical portion 17a that is metal-fitted to the outer member 2. And an inner diameter part 17b extending radially inward from the cylindrical part 17a.

  The seal member 18 is made of a synthetic rubber such as NBR, and has a side lip 18a extending obliquely outward in the radial direction, and a grease lip 18b and a dust lip 18c formed in a bifurcated shape on the inner diameter side. The side lip 18a is in sliding contact with a side surface on the outer side of the standing plate portion 14b of the slinger 14 via a predetermined axial shimiro, and the grease lip 18b and the dust lip 18c are in contact with the cylindrical portion 14a via a predetermined radial shimiro. Are in sliding contact. In addition to the exemplified NBR, examples of the material of the seal member 18 include ACM, FKM, or silicone rubber having excellent heat resistance and chemical resistance, such as HNBR and EPDM having excellent heat resistance. can do.

  Here, a face spline 13 is formed on the large end face of the inner ring 5 by plastic working. The face spline 13 meshes with a face spline formed on the constant velocity universal joint (not shown), and transmits rotational torque from the engine. The inner ring 5 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and as shown in FIG. 3, the outer ring surface 5a and the slinger 14 of the inner seal 10 are press-fitted. A predetermined hardened layer 19 (indicated by cross-hatching in the figure) is formed in the range of 58 to 64 HRC by induction hardening from the radial surface 5b to the small end surface 5c. Note that the face spline 13 and the inner diameter surface 5d are kept in the material hardness after forging.

  As shown in an enlarged view in FIG. 4, the face spline 13 has a tooth bottom formed on an arc surface having a predetermined radius of curvature R, and a pressure angle α is set in a range of 20 to 30 °. Here, if the pressure angle α is increased, the separating force at the time of torque load increases, while the torque transmission efficiency decreases. Further, if the pressure angle α is reduced, the root of the tooth becomes thinner, the strength of the tooth itself is lowered, and machining becomes difficult. In the present embodiment, the pressure angle α is set in a range of 20 to 30 °, and the root portion is formed in an arcuate surface, whereby the stress at the bottom portion generated at the time of driving torque load can be relieved and torque transmission efficiency and plasticity can be reduced. Both workability can be achieved.

  A serration (or spline) 20 is formed on the outer periphery of the small-diameter step portion 4b of the hub wheel 4 by rolling. Then, the inner ring 5 is press-fitted into the small-diameter step portion 4b of the hub ring 4 through a predetermined shimiro, and the serration 20 is closely fitted to the inner surface 5d of the unquenched inner ring 5 so that the hub ring 4 and the inner ring 5 are integrated. Bonded to the other, so-called press cut bonding.

  Here, the inner diameter d0 of the inner diameter surface 5d of the inner ring 5 is set to be smaller than the outer diameter d1 of the serration 20 of the small-diameter step portion 1b and larger than the root diameter d2 of the serration 20 (d1). > D0> d2). Then, by forming the tip of the serration 20 of the small-diameter step portion 1b of the hub wheel 4 at the edge, the serration 20 can be tightly fitted to the inner diameter surface 5d of the inner ring 5 while being easily cut and pressed. Cut waste generated at the time of joining can be discharged to the inner side without accumulating between the small diameter step 4b and the inner ring 5. By adopting such press-cut joining, it is possible to transmit a desired driving force, and to prevent loosening of the coupling portion between the hub wheel 4 and the inner ring 5 over a long period of time.

  As described above, in this embodiment, the face spline 13 is formed directly on the end surface of the inner ring 5, and furthermore, press-cut joining is performed so that the driving force can be transmitted between the inner ring 5 and the hub wheel 4, so that the weight / It is possible to provide a wheel bearing device that achieves compactness, reduces the number of processing steps, simplifies assembly work, and reduces costs. Further, since the pitch circle diameter PCDi of the inner side rolling element 3 is set larger than the pitch circle diameter PCDo of the outer side rolling element 3, the inner ring 5 can be made thicker and press cut It is possible to suppress deformation of the inner ring 5 at the time of joining and prevent the roundness of the inner rolling surface 5a from being lost.

  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 wheel bearing device in which a face spline is directly formed on an end face of an inner ring press-fitted and fixed to a hub ring.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a, 2b Outer rolling surface 2c Car body mounting flange 3 Rolling body 4 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step part 5 Inner ring 5b Outer surface 5c of inner ring Small end surface 5d of inner ring Inner ring inner surface 6 Wheel mounting flange 6a Bolt hole 6b Inner side base 7 and 8 of wheel mounting flange Cage 9 Outer side seal 10 Inner side seal 11, 17 Core metal 12, 18 Seal member 13 Face spline 14 Slinger 14a Cylindrical portion 14b Standing plate portion 15 Seal plate 16 Magnetic encoder 19 Hardened layer 20 of inner ring Serration 50 Hub wheel 51 Double row angular contact ball bearing 52 Constant velocity joint 53 Drive shaft 54, 70 Inner ring 55, 69 Outer ring 56, 71 Ball 57 , 72 Cage 58 Side wall 59, 76 Side face spline 60 Connection bolt 61 Head 62 Portion 62a Large-diameter portion 63 Through-hole 64 Male thread portion 65 Clamping nut 66 Hub shaft 66a, 69a, 70a Raceway surface 67 Flange 68 Hub bolt 73 Small-diameter shaft portion 74 External tooth spline 75 Internal tooth spline 77 Inner hole PCDi Inner side rolling element Pitch circle diameter of PCDo Pitch circle diameter of outer side rolling element α Face spline pressure angle R Curvature radius of face spline root

Claims (7)

An outer member integrally having a vehicle body mounting flange for being attached to the vehicle body on the outer periphery, and an outer rolling surface of a double row integrally formed on the inner periphery;
A wheel mounting flange for mounting the wheel at one end is integrally formed, one outer side rolling surface facing the outer side rolling surface of the double row on the outer periphery, and a cylindrical shape extending in the axial direction from the inner side rolling surface The inner ring is formed of a hub ring formed with a small-diameter step portion, and an inner ring that is press-fitted into the small-diameter step portion of the hub ring and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery. Direction member,
A double row rolling element housed so as to be freely rollable between both rolling surfaces of the inner member and the outer member;
A seal mounted on both side openings of an annular space formed between the outer member and the inner member;
In the wheel bearing device in which a face spline is formed on the large end surface of the inner ring,
A serration in which the pitch circle diameter of the inner side rolling elements of the double row rolling elements is set to be larger than the pitch circle diameter of the outer side rolling elements, and is hardened by induction hardening on the small diameter step portion of the hub wheel. And the hub ring and the inner ring are integrally press-cut joined to each other while the inner peripheral surface of the inner ring is unquenched and fitted into the serration while being cut. Bearing device.   The inner ring is made of medium-high carbon steel containing carbon of 0.40 to 0.80 wt%, and is surfaced by induction hardening from the inner rolling surface to the small end surface from the outer diameter surface into which the inner side seal is press-fitted. 2. The wheel bearing device according to claim 1, wherein a predetermined hardened layer is formed in a hardness range of 58 to 64 HRC, and the face spline and the inner diameter surface are kept in the material hardness after forging.   The wheel bearing device according to claim 1 or 2, wherein the face spline is formed by plastic working.   The wheel bearing device according to claim 1, wherein the serrations of the small diameter step portion are formed by rolling.   An inner diameter of the inner ring is set to be smaller than an outer diameter of the serration of the small diameter step portion and larger than a root diameter of the serration, and a tip of the serration of the small diameter step portion is formed at an edge. The wheel bearing device according to claim 1.   The hub ring is made of medium and high carbon steel containing carbon of 0.40 to 0.80 wt%, and is surfaced by induction hardening from the inner rolling surface to the small diameter step portion from the inner side base portion of the wheel mounting flange. The wheel bearing device according to claim 1, wherein the hardness is set in a range of 50 to 64 HRC.   The wheel bearing device according to any one of claims 1 to 3, wherein a tooth bottom portion of the face spline is formed on an arc surface having a predetermined radius of curvature, and a pressure angle is set in a range of 20 to 30 °.

Images