JP2015016777A - Bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel that prevents occurence of a burr at the time of turning a lateral face of a wheel mounting flange and is reduced in weight, and is reduced in costs by reduction of weight of charged forging and a quantity of lathe-turning.SOLUTION: In a bearing device for a wheel, bolt insertion holes 10 into which hub bolts 6a are inserted are pressed at equal intervals in a circumferential direction of a wheel mounting flange 6 are formed and non-circular shaped penetration holes 11 for achieving lightweight are formed between the bolt insertion holes 10, and an outer-side lateral surface 6c of the wheel mounting flange 6 is subjected to a cutting process. The penetration holes 11 are formed in a fan shape, comprised of an outline portion A in a radial direction and outline portions B1 and B2 in a circumferential direction. In corners of the portions are formed circular-arc surfaces with curvature radii r1 and r2 equal to R2 or more, and in outer-side edges of the penetration holes 11 are formed chamfers 12, where the chamfers 12 and the penetration holes 11 are formed by forging processing.

Description

  The present invention relates to a wheel bearing device that supports a wheel of an automobile or the like, and more particularly, to a wheel bearing device that achieves weight reduction and cost reduction by reducing forging input weight and turning amount.

  In recent years, demands for improving fuel efficiency have been severe from the viewpoint of resource saving or pollution. In automobile parts, the weight reduction of wheel bearing devices has been attracting attention as a factor to meet such demands and has been strongly desired for a long time. In particular, among vehicles such as automobiles, light vehicles such as light four-wheel vehicles or small cars are not only cost-reduced, but demands for this weight reduction are increasing.

  There are various proposals related to wheel bearing devices that have been made lighter in the past. However, in the wheel bearing device that supports the wheel in a freely rotatable manner, reliability and durability contradicting this weight reduction in one aspect. Improving the performance is also an important factor.

  The wheel bearing device shown in FIG. 7 is a typical one. In this wheel bearing device, the central area 52 of the hub wheel 51 is formed in a conical shape with respect to the rotation axis 53, and the diameter of the central area 52 decreases from the radially outer side toward the bearing area 54. . The central section 52 transitions to a wheel mounting flange 56 to which a brake rotor and a wheel (not shown) fitted onto the pilot portion 55 of the hub wheel 51 are mounted at the periphery of the maximum diameter. A hub bolt (not shown) to which the brake rotor and the wheel are fastened is fixed to a bolt insertion hole 57 formed at a circumferentially equidistant position of the wheel mounting flange 56.

  Further, through holes 58 are formed in the wheel mounting flange 56, and are similarly distributed between the bolt insertion holes 57. The through hole 58 has a substantially trapezoidal cross-sectional shape. The longer side with respect to the periphery of the through hole 58 is on the radially outer side of the wheel mounting flange 56, and the shorter side is the wheel mounting flange 56. Is formed on the radially inner side.

  Each corner of the through hole 58 is formed in an arc shape, and a chamfered portion is formed at the edge of the through hole 58. As a result, the weight can be reduced and the stress generated in the hub wheel 51 can be reduced (see, for example, Patent Document 1).

Special table 2009-520642 gazette

  However, in this conventional hub wheel 51, a circumferential groove is formed in a region where the bolt insertion hole 57 and the through hole 58 are formed on the side surface of the wheel mounting flange 56, and the outer diameter of the circumferential groove is The surface which contacts a brake rotor is provided in the side and inner diameter side. In this case, the surfaces that contact the brake rotor are only on the outer diameter side and the inner diameter side of the circumferential groove, and the surface that receives the axial force that is applied when the bolt is tightened with the wheel nut is narrow. The contact area decreases and the surface pressure increases. Therefore, in general, the circumferential groove is abolished so that the entire wheel mounting flange is in contact with the brake rotor. With such a structure, the entire side surface of the wheel mounting flange 56 is turned. When doing so, there is a risk that burrs may occur in the radial contour portion of the through hole 58. In particular, when the through hole 58 has a circular shape like the bolt insertion hole 57, the burr can be easily removed with a tool such as a drill. However, if the through hole 58 has a non-circular shape such as a substantially trapezoid, the burr is generated. There are two parts of the straight part that faces the axis, but in order to remove this burr, it must be manually removed or machined with a program, which increases work man-hours and costs. .

  The present invention has been made in view of such circumstances, paying attention to the problem specific to the weight reduction hole of the non-circular through hole, and preventing the occurrence of burrs when turning the side surface of the wheel mounting flange. An object of the present invention is to provide a wheel bearing device that is reduced in weight and reduced in cost by reducing forging input weight and turning amount.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel attachment for attaching a wheel to one end. From a hub ring integrally having a flange and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring fitted to the small-diameter step portion of the hub ring or an outer joint member of a constant velocity universal joint An inner member having a double row inner rolling surface facing the outer row rolling surface of the double row on the outer periphery, and freely rollable via a cage between the inner member and the outer member. A double-row rolling element accommodated therein, and a bolt insertion hole into which a hub bolt is press-fitted in the circumferential direction of the wheel mounting flange, and a non-circular through hole for weight reduction between the bolt insertion holes. Formed and the outer side surface of the wheel mounting flange was cut In wheel bearing device, the chamfered portion is formed on the outer side edge of the through hole, the through hole and the chamfered portion is formed by forging.

  In this way, a bolt insertion hole into which the hub bolt is press-fitted in the circumferential direction of the wheel mounting flange of the hub wheel and a non-circular through hole for weight reduction are formed between the bolt insertion holes. In the wheel bearing device in which the outer side surface of the flange is cut, a chamfered portion is formed on the outer side edge of the through hole, and the chamfered portion and the through hole are formed by forging. It is possible to prevent the occurrence of burrs when turning the outer side of the wheel, reduce the weight of the hub wheel and reduce the weight of forging, and reduce the cutting range of at least the outer side of the wheel mounting flange. Thus, it is possible to reduce the cutting amount, and it is possible to provide a wheel bearing device that achieves cost reduction.

  According to a second aspect of the present invention, the through hole is formed in a shape including a radial contour portion and a circumferential contour portion, and an arc surface is formed at the corner of these portions. Thus, it is possible to effectively reduce the weight without reducing the strength and rigidity of the wheel mounting flange.

  Further, as in the third aspect of the present invention, if the through hole is any one of a fan shape, a trapezoidal shape, and a triangular shape, it is more effective while ensuring strength and rigidity than a circular shape. The weight can be reduced.

  Further, as in the invention according to claim 4, if the radius of curvature of the arcuate surface of the corner is set to R2 or more, the stress generated by the load repeatedly applied to the wheel mounting flange can be relieved. And durability can be ensured.

  If the cross section of the chamfered portion has an arc surface and a tapered surface as in the invention described in claim 5, the connecting portion with the through hole becomes smooth and the turning end point angle is constant. Thus, even if the side turning allowance varies, the generation of burrs can be stably prevented.

  Moreover, if the inclination angle of the tapered surface is set in a range of 45 ° to 60 ° as in the invention described in claim 6, it is possible to suppress the generation of burrs and to reduce the side surface of the wheel mounting flange. The variation in the area can be suppressed, the contact area with the brake rotor can be reduced and the surface pressure can be prevented from increasing, and the strength and rigidity of the wheel mounting flange can be ensured.

  Further, as in the seventh aspect of the present invention, if the outer edge of the through hole is finished with a grinding wheel, the burr generated during the turning of the side surface of the wheel mounting flange is surely removed. can do.

  The wheel bearing device according to the present invention integrally has an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel mounting flange for mounting the wheel on one end, and on the outer periphery. A hub ring formed with a small-diameter step portion extending in the axial direction, and an outer joint member of at least one inner ring or a constant velocity universal joint fitted to the small-diameter step portion of the hub ring, the outer periphery of the double row on the outer periphery An inner member in which a double row of inner rolling surfaces facing the rolling surface is formed, and a double row of rolling elements housed between the inner member and the outer member via a cage so as to be freely rollable. A bolt insertion hole into which a hub bolt is press-fitted in the circumferential direction of the wheel mounting flange, and a non-circular through hole for weight reduction is formed between the bolt insertion holes. In the wheel bearing device whose side surface is machined, Since the chamfered portion is formed at the outer edge of the through hole, and the chamfered portion and the through hole are formed by forging, it is possible to prevent the occurrence of burrs when turning the outer side surface of the wheel mounting flange. It is possible to reduce the weight of the hub wheel and reduce the weight of forging, and at the same time, the cutting range of at least the outer side surface of the wheel mounting flange can be reduced to reduce the cutting amount, thereby reducing the cost. A wheel bearing device can be provided.

It is a longitudinal cross-sectional view which shows the periphery of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the wheel bearing apparatus of FIG. FIG. 3 is a front view showing the hub wheel of FIG. 2. (A) is principal part sectional drawing which shows the through-hole of FIG. 3, (b) is the elements on larger scale of (a). It is the elements on larger scale which show the modification of FIG.4 (b). It is principal part sectional drawing which shows the modification of Fig.4 (a). It is a perspective view which shows the hub ring of 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 integrally formed and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub wheel An inner member comprising an inner ring that is press-fitted into a small-diameter step portion and has an inner race surface formed opposite to the other outer race surface of the double row on the outer periphery, and is held between the inner member and the outer member. A double-row rolling element housed so as to be freely rollable via a device, and a bolt insertion hole into which a hub bolt is press-fitted in the circumferential direction of the wheel mounting flange, and a weight reduction between these bolt insertion holes The non-circular through hole is formed, and the outer surface of the wheel mounting flange In the wheel bearing device in which the side surface is cut, the through hole is formed in a sector shape including a radial contour portion and a circumferential contour portion, and an arc having a radius of curvature equal to or greater than R2 at the corners of these portions. A surface is formed, and a chamfered portion is formed on the outer edge of the through hole. The chamfered portion and the through hole are formed by forging.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing the periphery of a wheel bearing device according to the present invention, FIG. 2 is a longitudinal sectional view showing the wheel bearing device of FIG. 1, and FIG. 3 is a front view showing the hub wheel of FIG. 4 (a) is a cross-sectional view of the main part showing the through-hole of FIG. 3, (b) is a partially enlarged view of (a), and FIG. 5 is a partially enlarged view showing a modification of FIG. FIG. 6 is a cross-sectional view of an essential part showing a modification 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).

  The wheel bearing device shown in FIG. 1 includes an inner member 1, an outer member 2, and double-row rolling elements (balls) 3 and 3. The inner member 1 includes a hub wheel 4 integrally having a wheel mounting flange 6 at an end portion on the outer side and a separate inner ring 5. Hub bolts 6 a are planted at equal intervals in the circumferential direction of the wheel mounting flange 6, and the wheels W are mounted via the brake rotor R. The outer member 2 integrally has a vehicle body mounting flange 2b on the outer periphery, is fitted inside the knuckle K, and is attached via a fixing bolt B.

  This wheel bearing device is for a driven wheel called the third generation, and as shown in an enlarged view in FIG. 2, the hub wheel 4 has an inner rolling surface 4a on one side (outer side) on the outer periphery, A small-diameter step 4b extending in the axial direction from the inner rolling surface 4a is formed.

  The inner ring 5 is formed with the other (inner side) inner raceway surface 5a on the outer periphery and is press-fitted into the small-diameter stepped portion 4b of the hub wheel 4 to form a back-to-back type double row angular contact ball bearing. It is fixed to the hub wheel 4 in the axial direction in a state where a predetermined bearing preload is applied by a caulking portion 4c formed by plastically deforming the end portion of 4b radially outward. The inner ring 5 and the rolling element 3 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  The hub wheel 4 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 4a and the base portion 6b on the inner side of the wheel mounting flange 6 are connected to the small diameter step portion 4b. Thus, the surface is hardened in a range of 58 to 64 HRC by induction hardening. The caulking portion 4c is an unquenched portion with the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 6, the fretting resistance of the small-diameter step portion 4b serving as the fitting portion of the inner ring 5 is improved, and the minute There is no occurrence of cracks and the like, and the plastic working of the caulking portion 4c can be performed smoothly.

  On the other hand, the outer member 2 is integrally formed with double row outer rolling surfaces 2a, 2a facing the double row inner rolling surfaces 4a, 5a of the inner member 1 on the inner periphery. Between these two rolling surfaces, double-row rolling elements 3 and 3 that are circumferentially arranged by a cage 7 are accommodated so as to roll freely.

  A seal 8 is attached to the outer opening of the annular space formed between the outer member 2 and the inner member 1, and a cap 9 is attached to the inner opening. This prevents leakage of grease sealed inside the bearing and intrusion of rainwater and dust from the outside into the bearing.

  Similar to the hub wheel 4, the outer member 2 is formed of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and at least the double row outer raceway surfaces 2a and 2a have surface hardness by induction hardening. Is cured in the range of 58 to 64 HRC.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the rolling element 3 as the ball | bowl was illustrated here, it is not restricted to this but is comprised by the double row tapered roller bearing which used the tapered roller for the rolling element 3. It may be what was done. Further, the third generation structure on the driven wheel side is illustrated, but the structure is not limited to this. For example, the structure is a first generation to fourth generation structure including a second generation structure in which a pair of inner rings are press-fitted into a hub ring. May be.

  Here, a plurality of bolt insertion holes 10 into which the hub bolts 6 a are press-fitted into the wheel mounting flange 6 of the hub wheel 4 (here, five) are formed, and the bolt insertion holes 10 are penetrated for weight reduction. A hole 11 is formed. These bolt insertion holes 10 and through holes 11 are formed in the forging process of the hub wheel 4.

  The through hole 11 is formed in a sector shape including a radial contour portion (straight line portion) A and circumferential contour portions (arc portions) B1 and B2. Thereby, weight reduction can be achieved effectively without reducing the strength and rigidity of the wheel mounting flange 6. And each corner of the through-hole 11 is formed in the circular arc surface which consists of predetermined curvature radius r1, r2 by forge processing. The corner radii of curvature r1 and r2 are set to R2 or more. Thereby, the stress which generate | occur | produces by the load repeatedly loaded on the wheel mounting flange 6 can be relieve | moderated, and durability can be ensured.

  On the other hand, a chamfered portion 12 is formed on the outer edge of the through hole 11 by forging. The chamfered portion 12 is formed in an arcuate surface having a predetermined radius of curvature r3 as shown in an enlarged view in FIG. Thereafter, at least the outer side surface 6c of the wheel mounting flange 6 is formed with desired dimensions and precision by turning (cutting) processing (indicated by a two-dot chain line in the figure). In the present embodiment, the chamfered portion 12 is formed in advance at the edge of the through hole 11 so that the chamfered portion 12 remains even after the outer side surface 6c is turned. It is possible to prevent the occurrence of burrs during turning of the side surface 6c, reduce the weight of the hub wheel 4 and reduce the weight of forging, and at least the cutting range of the outer side surface 6c of the wheel mounting flange 6. As a result, the amount of cutting can be reduced, and a wheel bearing device can be provided that achieves cost reduction.

  In addition, although the through-hole 11 illustrated fan shape, it is not restricted to this, A non-circular shape, such as trapezoid shape and triangular shape, may be sufficient. Thereby, compared with circular shape, weight reduction can be achieved effectively. Here, the chamfered portion 12 is formed over the entire periphery of the through-hole 11. However, the occurrence of the burr is a moment when the turning tip is separated from the workpiece by the turning process. That is, the chamfered portion 12 may be formed only in the radial direction contour portion A (see FIG. 2).

  In the case of the chamfered portion 12 having an arcuate cross section, as shown in FIG. 4B, if the tangent angle α of the chamfered portion 12 varies due to variations in the turning allowance T, for example, if the turning allowance T is large, The angle α becomes small and burrs are likely to occur. Therefore, as shown in FIG. 5, if the chamfered portion 13 includes an arc surface 13a having a predetermined radius of curvature r4 and a tapered surface 13a having an inclination angle β, the connecting portion with the through hole 11 becomes smooth. At the same time, the end point angle of the turning process is constant, and the occurrence of burrs can be stably prevented even if the turning allowance T of the side surface 6c varies.

  Here, the inclination angle β of the tapered surface 13b of the chamfered portion 13 is set in a range of 45 ° to 60 °. If this inclination angle β is less than 45 °, it is difficult to suppress the occurrence of burrs. If it exceeds 60 °, the variation in the area of the side surface 6c increases, and the contact area with the brake rotor (not shown) decreases. As a result, the surface pressure increases, and the strength and rigidity of the wheel mounting flange 6 decrease.

  In addition, when the through hole 11 has a fan shape as in the present embodiment, the chamfered portions 12 and 13 cannot be processed with a commercially available cutter or the like, so the edge on the outer side of the through hole 11 is hand-held as shown in FIG. Finishing may be performed by a grinding wheel 14 such as a grinder. In this case, the radial contour portion, the circumferential contour portion and the corner portion can be easily machined along the edge of the through hole 11, and the burr generated during the turning of the side surface 6c can be reliably removed.

  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 present invention can be applied to a wheel bearing device having a first generation to a fourth generation structure including a hub ring integrally having a wheel mounting flange.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a Outer rolling surface 2b Car body mounting flange 3 Rolling body 4 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step part 4c Clamping part 5 Inner ring 6 Wheel mounting flange 6a Hub bolt 6b Wheel mounting flange Inner side base 6c Outer side surface 7 of wheel mounting flange 7 Cage 8 Seal 9 Cap 10 Bolt insertion hole 11 Through hole 12, 13 Chamfered portion 13a Arc surface 13b Tapered surface 14 Grinding wheel 51 Hub wheel 52 Central area 53 Rotating axis 54 Bearing area 55 Pilot portion 56 Wheel mounting flange 57 Bolt insertion hole 58 Through hole A Radial contour portion B1, B2 Circumferential contour portion B Fixing bolt K Knuckle r1, r2 Curvature radius r3, r4 chamfered portion of through hole Radius of curvature R Brake rotor T Turning allowance W Wheel α Tangent angle β Inclination angle

Claims (7)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end thereof and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring fitted to the small-diameter step portion of the hub ring Or an inner member formed of an outer joint member of a constant velocity universal joint and having a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery;
A double row rolling element housed in a freely rollable manner between the inner member and the outer member via a cage;
Bolt insertion holes into which hub bolts are press-fitted at equal intervals in the circumferential direction of the wheel mounting flange, and non-circular through holes for weight reduction are formed between these bolt insertion holes, and the outer side surface of the wheel mounting flange In the wheel bearing device machined with
A wheel bearing device, wherein a chamfered portion is formed on an outer edge of the through hole, and the chamfered portion and the through hole are formed by forging.   2. The wheel bearing device according to claim 1, wherein the through-hole is formed in a shape including a radial contour portion and a circumferential contour portion, and an arc surface is formed at a corner portion of these portions.   3. The wheel bearing device according to claim 1, wherein the through hole has a fan shape, a trapezoidal shape, or a triangular shape.   The wheel bearing device according to claim 2, wherein a radius of curvature of the arcuate surface of the corner is set to R2 or more.   The wheel bearing device according to claim 1, wherein a cross section of the chamfered portion includes an arc surface and a tapered surface.   The wheel bearing device according to claim 5, wherein an inclination angle of the tapered surface is set in a range of 45 ° to 60 °.   The wheel bearing device according to any one of claims 1 to 3, wherein the outer edge of the through hole is finished with a grinding wheel.

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