JP2006137297A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel reduced in weight, miniaturized, and improved in strength and durability of a hub wheel under the condition of a rotary bending load. <P>SOLUTION: This bearing device for a wheel is provided with an outside member 2, an inside member 1 integrally having a wheel fitting flange 6 in one end thereof and formed of a hub wheel 4, which is formed with an inside rolling surface 4a and a small-diameter stage part 4b in the periphery thereof, and an inner ring 5 pressed into the small diameter stage part 4b, and a plurality of lines of rolling elements 3 housed between both of the rolling surfaces of the inside member 1 and the outside member 2. A predetermined hardening layer 11 is formed in the peripheral surface of the wheel fitting flange 6 over from a base part 10 on an inboard side to the inside rolling surface 4a and the small-diameter stage part 4b, and parts corresponding to the base part 10 and the inside rolling surface 4a are formed hollow, and the inner peripheral surface 15 is formed with a hardening layer 17. A non-hardening layer is provided between both the hardening layers 11 and 17. With this structure, strength and durability of the hub wheel 4 can be secured, and the hub wheel 4 can be formed thin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  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 improves the strength and durability of a hub wheel integrally having a wheel mounting flange.

  A wheel bearing device for rotatably supporting a wheel of an automobile or the like has a structure in which a double row rolling bearing with a seal called a first generation is used independently, and has a body mounting flange integrally formed on an outer member. Evolved into the second generation, and the third generation in which one inner rolling surface of a double row rolling bearing is integrally formed on the outer periphery of the hub wheel integrally having a wheel mounting flange. The fourth generation has been developed in which the joint is integrated and the other inner rolling surface of the double row rolling bearing is integrally formed on the outer periphery of the outer joint member constituting the constant velocity universal joint.

  In this type of wheel bearing device, a vehicle load and a turning lateral load are repeatedly loaded with a bending moment or the like on the wheel mounting flange and the bearing portion of the hub wheel from the tire contact surface through the wheel. Since a raw material of medium carbon steel (surface hardness of 15 to 25 HRC) such as S53C is used as the material of the hub wheel, there is a risk of insufficient strength and durability against the load.

  Therefore, the present applicant has proposed a wheel bearing device as shown in FIG. 5 in order to solve the problem of insufficient strength and durability of the hub wheel. This is a wheel bearing device 50 called a third generation on the driven wheel side, and integrally includes a vehicle body mounting flange 51b attached to a knuckle (not shown) constituting a suspension device on the outer periphery. The outer member 51 having the double-row outer rolling surfaces 51a and 51a and the wheel mounting flange 52 to which a wheel (not shown) is attached at one end are integrally formed, and the double-row outer rolling surfaces 51a and 51a are integrally formed on the inner periphery. A hub wheel 53 formed with an inner rolling surface 53a facing one of the outer rolling surfaces 51a, 51a, a small shaft-shaped step portion 53b extending in the axial direction from the inner rolling surface 53a, and the hub wheel 53. An inner member 55 comprising an inner ring 54 formed on the outer periphery with an inner rolling surface 54a that is press-fitted into the small-diameter step portion 53b of the double row and opposed to the other of the double-row outer rolling surfaces 51a, 51a. Housed between the member 55 and the outer member 51, And a rolling element 56 rollably retained double row in vessel 57. And the inner ring | wheel 54 is being fixed to the axial direction by the crimping part 53c formed by carrying out the plastic deformation of the edge part of the small diameter step part 53b of the hub ring | wheel 53 to radial direction outward. Further, seals 58 and 59 are attached to both ends of the outer member 51 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater, dust, etc. into the bearing from the outside.

The hub wheel 53 is made of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and is induction-hardened from the seal land portion where the seal 58 is slidably contacted to the inner rolling surface 53a and the small diameter step portion 53b. As a result, a hardened layer 60 (indicated by cross-hatching in the figure) having a surface hardness of 58 HRC or more is formed, and the high frequency is also applied to the range extending from the base end of the side surface 52a of the wheel mounting flange 52 to the outer peripheral surface of the brake pilot portion 61 A hardened layer 62 (indicated by cross-hatching in the figure) having a surface hardness of 40 HRC or more is formed by quenching. As a result, the seal land as the base of the wheel mounting flange 52 not only has improved wear resistance, but also has sufficient mechanical strength against the bending moment applied to the wheel mounting flange 52, and the hub wheel 53. Strength and durability are improved.
JP 2004-182127 A

  In such a conventional wheel bearing device, a brake extends from the seal land portion where the seal 58 is slidably contacted to the outer peripheral surface of the inner rolling surface 53a and the small diameter step portion 53b, and further from the base end portion of the side surface 52a of the wheel mounting flange 52. Hardened layers 60 and 62 are formed in a range extending over the outer peripheral surface of the pilot portion 61, and the strength and durability of the hub wheel 53 are improved. However, recently, the demand for weight reduction of the wheel bearing device that directly leads to the improvement of fuel efficiency from the viewpoint of resource saving or pollution is becoming more and more severe. Under these circumstances, if the hub ring is made thinner for further weight reduction, the weakest part may move from the outer peripheral surface to the inner peripheral surface, and the hub ring may be damaged starting from the inner peripheral surface. There is.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device that is lightweight and compact, and that has improved the strength and durability of a hub wheel under rotational bending load conditions. The purpose is that.

  In order to achieve the object, the invention according to claim 1 of the present invention has an outer member having a double row outer rolling surface on the inner periphery, a wheel mounting flange at one end, and an outer periphery. An inner ring comprising a hub wheel formed with a small-diameter step portion and an inner ring press-fitted into the small-diameter step portion of the hub wheel, and having a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery. In a wheel bearing device comprising a member and a double row rolling element that is rotatably accommodated between the rolling surfaces of the inner member and the outer member, a wheel mounting flange of the hub wheel is provided. A configuration was adopted in which a predetermined hardened layer was formed by induction hardening on the outer peripheral surface extending from the base portion on the inboard side to the small-diameter stepped portion and the inner peripheral surface of the hub wheel corresponding thereto.

  As described above, in the wheel bearing device including the hub wheel having the wheel mounting flange integrally formed at one end and the small-diameter stepped portion formed on the outer periphery, the small diameter from the base on the inboard side of the wheel mounting flange in the hub wheel. A predetermined hardened layer is formed by induction hardening on the outer peripheral surface over the step and the corresponding inner peripheral surface of the hub ring, improving the strength and durability of the hub ring under the condition of rotational bending load A wheel bearing device can be provided.

  Preferably, as in the invention according to claim 3, one inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery of the hub wheel, and predetermined hardening is performed on the inner rolling surface. A layer is formed, and the hardened layer is stopped at an end portion of the small-diameter step portion, and the inner ring is fixed in the axial direction by a crimping portion formed by plastically deforming the end portion radially outward. Then, it has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange, and the strength and durability of the hub wheel are improved. In addition, the workability when plastically deforming the caulking portion is improved, and the occurrence of cracks and the like during processing is prevented, and the quality reliability is improved.

  More preferably, as in the invention described in claim 3, the radial inner portion corresponding to the base portion and the inner rolling surface of the wheel mounting flange is formed in a hollow shape, and a hardened layer is formed on the inner peripheral surface. If a non-hardened layer is provided between both hardened layers, the strength and durability of the hub wheel can be ensured and the wall thickness can be reduced.

  According to a fourth aspect of the present invention, a predetermined hardened layer is formed at a corner extending from the base end portion of the side surface of the outboard in the wheel mounting flange to the outer peripheral surface of the brake pilot portion where the brake rotor is supported. If so, the strength and durability of the hub wheel can be further improved, and the wheel mounting flange can be made ribbed or thin.

  Further, in the invention according to claim 5, since serration as torque transmitting means is formed on the inner periphery of the hub wheel, and a predetermined hardened layer is formed on the surface of the serration, the wear resistance of the serration is reduced. By improving the strength, the effective length of the serration can be shortened, and the hub wheel can be made lighter and more compact in the wheel bearing device on the drive wheel side.

  A wheel bearing device according to the present invention includes an outer member having a double row outer rolling surface on the inner periphery, a wheel mounting flange at one end, and a hub wheel having a small-diameter step formed on the outer periphery. And an inner member having an inner ring press-fitted into a small-diameter step portion of the hub wheel, and having an inner rolling surface of a double row opposite to the outer rolling surface of the double row on the outer periphery, the inner member and the In the wheel bearing device including a double row rolling element that is rotatably accommodated between the rolling surfaces of the outer member, the small diameter step from the base on the inboard side of the wheel mounting flange in the hub wheel. A predetermined hardened layer is formed on the outer peripheral surface over the part and the corresponding inner peripheral surface of the hub wheel, so that the wheel has improved strength and durability under the condition of rotating bending load. A bearing device can be provided.

  A vehicle body mounting flange is integrally formed on the outer periphery, an outer member having a double row outer rolling surface formed on the inner periphery, a wheel mounting flange is integrally formed on one end, and the double row outer rolling is formed on the outer periphery. One inner rolling surface facing the running surface, a hub wheel formed with a small-diameter step portion extending in the axial direction from the inner rolling surface, and press-fitted into the small-diameter step portion of the hub wheel, and the double row on the outer periphery An inner member formed of an inner ring formed with the other inner rolling surface opposite to the outer rolling surface of the inner rolling member, and a double row of rolling elements accommodated between both rolling surfaces of the inner member and the outer member. In the wheel bearing device including a moving body, a predetermined hardened layer is formed on the outer peripheral surface extending from the base portion on the inboard side of the wheel mounting flange in the hub wheel to the inner rolling surface and the small diameter step portion, The base portion of the wheel mounting flange and the radially inner portion corresponding to the inner rolling surface are hollow. While being formed, of which the cured layer on the peripheral surface is formed, the non-hardened layer is provided on both cured layers.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, and FIG. 2 is an enlarged view showing a single hub wheel. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing).

  This wheel bearing device is called the third generation on the driven wheel side, and is composed of an inner member 1, an outer member 2, and double-row rolling elements (balls) 3, 3 accommodated between both members. ing. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4.

  The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at one end, an inner rolling surface 4a on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface 4a. Part 4b is formed. Hub bolts 6a for fixing a wheel (not shown) are implanted at equal circumferential positions of the wheel mounting flange 6. The inner ring 5 has an inner raceway surface 5a formed on the outer periphery, and is press-fitted into the small-diameter step portion 4b of the hub ring 4 through a predetermined shimiro. The end portion of the small-diameter step portion 4b of the hub wheel 4 is plastically deformed radially outward to form a caulking portion 4c, and the inner ring 5 is fixed in the axial direction by the caulking portion 4c. This type of structure is called a self-retained structure, and it is not necessary to control the preload by tightening firmly with a nut or the like as in the prior art. The amount of preload can be maintained for a period.

  On the other hand, the outer member 2 integrally has a vehicle body mounting flange 2b for mounting to the vehicle body (not shown) on the outer periphery, and double-row outer rolling facing the inner rolling surfaces 4a and 5a on the inner periphery. Surfaces 2a and 2a are formed. And the double row rolling elements 3 and 3 are accommodated between these rolling surfaces, respectively, and are hold | maintained by the holder | retainers 7 and 7 so that rolling is possible. Further, seals 8 and 9 are attached to both ends of the outer member 2 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater, dust, etc. into the bearing from the outside.

  The outer member 2 is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon, such as S53C, and the end to which the seals 8 and 9 are fitted, including the double row outer rolling surfaces 2a and 2a. The surface hardness is hardened to a range of 54 to 64 HRC, preferably 58 to 64 by induction hardening over the inner diameter surface of the part.

  The hub wheel 4 is made of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and as shown in an enlarged manner in FIG. A hardened layer 11 (indicated by cross hatching in the figure) is formed by induction hardening over the rolling surface 4a and the small diameter step 4b. The hardened layer 11 has a surface hardness of 54 to 64 HRC, preferably 58 to 64 HRC, and a hardened layer depth of 0.5 to 3 mm. The caulking portion 4c is an unquenched portion having a surface hardness of 25HRC or less after forging.

  With such an induction hardening pattern, the seal land 10 serving as the base of the wheel mounting flange 6 not only has improved wear resistance, but also has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 6. The strength and durability of the hub wheel 4 are improved. In addition, the workability when plastically deforming the caulking portion 4c is improved, and the occurrence of cracks and the like during the processing is prevented, and the reliability of the quality is improved. The inner ring 5 is made of a high carbon chrome bearing steel such as SUJ2, and is hardened in the range of 58 to 64 HRC up to the core part by quenching.

  Further, induction hardening is also applied to a corner (stealing portion) 13 extending from the base end portion of the side surface 6b of the wheel mounting flange 6 in contact with the brake rotor (not shown) to the outer peripheral surface of the brake pilot portion 12 on which the brake rotor is supported. As a result, a hardened layer 14 (indicated by cross-hatching in the figure) having a surface hardness of 54 HRC or more and a hardened layer depth of 0.5 to 3 mm is formed. Since the hardened layer 14 is formed at the base of the wheel mounting flange 6 in the hub wheel 4 as described above, the strength and durability of the hub wheel 4 can be further improved, and the wheel mounting flange 6 can be ribbed or thinned. Can be realized.

  Further, in the present embodiment, the radially inner portion corresponding to the seal land portion 10 and the inner rolling surface 4a is formed in a hollow shape with the aim of reducing the weight, and the inner peripheral surface of the brake pilot portion 12 from the inner peripheral surface 15 thereof. A hardened layer 17 (shown by cross-hatching in the figure) having a surface hardness of 54 HRC or more and a hardened layer depth of 0.5 to 3 mm is formed in a range extending to 16 by induction hardening. A non-hardened layer is provided between the hardened layer 17 on the inner peripheral surface side and the hardened layer 11 on the outer peripheral surface side. With such a quenching pattern, it is possible to provide a wheel bearing device that can reduce the thickness of the hub wheel 4 and improve the strength and durability of the hub wheel 4 under the condition of rotational bending load.

  Here, the wheel bearing device of the third generation structure in which the inner rolling surface 4a is directly formed on the outer periphery of the hub wheel 4 is illustrated, but the wheel bearing device according to the present invention is not limited to such a structure, for example, A first generation or second generation structure in which a pair of inner rings are press-fitted into a small-diameter step portion of the hub ring may be used. In addition, although the double row angular contact ball bearing which used the rolling elements 3 and 3 as a ball | bowl was illustrated, it may be a double row tapered roller bearing which uses a tapered roller for not only this but a rolling element.

  FIG. 3 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention, and FIG. 4 is an enlarged view showing a single hub wheel. This embodiment is a third generation wheel bearing device on the drive wheel side, and the same parts, the same parts, or the parts having the same functions as those of the above-mentioned embodiments are denoted by the same reference numerals and detailed description thereof will be given. Omitted.

  The wheel bearing device includes an inner member 18, an outer member 2, and double-row rolling elements 3 and 3 accommodated between the two members. The inner member 18 includes a hub ring 19 and an inner ring 5 press-fitted into the hub ring 19.

  In this wheel bearing device, the hub wheel 19 integrally has a wheel mounting flange 6 at one end, an inner rolling surface 19a on the outer periphery, and a cylindrical small diameter step extending in the axial direction from the inner rolling surface 19a. A portion 19b is formed, and a serration (or spline) 19c into which an outer joint member constituting a constant velocity universal joint (not shown) is fitted is formed on the inner periphery. As in the above-described embodiment, the hub wheel 19 is made of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C. As shown in an enlarged view in FIG. A hardened layer 21 is formed by induction hardening from the seal land portion 20 in sliding contact to the inner rolling surface 19a and the end of the small diameter step portion 19b. The hardened layer 21 has a surface hardness of 54 to 64 HRC, preferably 58 to 64 HRC, and a hardened layer depth of 0.5 to 3 mm.

  Further, a corner portion 22 is formed between the side surface 6b of the wheel mounting flange 6 and the cylindrical brake pilot portion 12 serving as a support surface of the brake rotor (not shown). The corner 22 is formed in an arc surface having a predetermined radius of curvature. The radius of curvature of the corner 22 is set to such an extent that the brake rotor does not interfere, and the hardened layer 23 having a surface hardness of 54 HRC or more and a hardened layer depth of 0.5 to 3 mm is also applied to the corner 22 by induction hardening. Is formed.

  Further, the portion corresponding to the seal land portion 20 and the inner rolling surface 19a is formed in a hollow shape, and the surface hardness is 54HRC by induction hardening in a range extending from the inner peripheral surface 24 to the inner peripheral surface 16 of the brake pilot portion 12. As described above, the hardened layer 25 having a hardened layer depth of 0.5 to 3 mm (indicated by cross hatching in the figure) is formed, and a non-hardened layer is provided between the hardened layers 21 and 25. As a result, the hub wheel 19 can be thinned, and the strength and durability of the hub wheel 19 can be improved under the condition of rotational bending load.

  A predetermined hardened layer 26 (indicated by cross hatching in the figure) is also formed on the surface of the serration 19c by induction hardening. As a result, the wear resistance of the serration 19c is improved, and the effective length of the serration 19c can be shortened by increasing its strength, and the hub wheel 19 can be made lighter and more compact.

  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 first to fourth generation wheel bearing devices including a hub wheel integrally having a wheel mounting flange.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is an expanded sectional view which shows a hub ring single-piece | unit same as the above. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is an expanded sectional view which shows a hub ring single-piece | unit same as the above. (A) is a longitudinal cross-sectional view which shows the conventional bearing device for wheels. (B) is the principal part enlarged view same as the above.

Explanation of symbols

1, 18 ... Inner member 2 ... Outer member 2a・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outside rolling surface 2b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 3 ・... rolling elements 4, 19 ... hub wheels 4a, 5a, 19a ..... Inner rolling surface 4b, 19b ..... Small diameter step 4c ... ······································ 5・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 6a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub bolt 6b ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ Side 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 8, 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... Seal 10, 20, ... Seal land 11, 14, 17, 21, 23, 25, 26 ... Hardened layer 12 ... Brake pilot parts 13, 22 ... Corners 15, 16, 24 ...・ ・ ・ ・ ・ ・ ・ ・ ・ Inner peripheral surface 19c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Serration 50 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... Wheel bearing device 51 ... Outer member 51a ... ..Outer rolling surface 51b 52 ... Wheel mounting flange 52a ... Side 53 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub wheel 53a, 54a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner rolling surface 53b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・········· Small diameter step 53c .... Inner ring 55 ... Inner member 56 ... ... Rolling elements 57 ... Cage 58, 59 ... 62 ... Hardened layer 61 ... Brake Pilot part

Claims (5)

An outer member having a double row outer rolling surface on the inner periphery;
The hub wheel is integrally formed with a wheel mounting flange at one end and a small diameter step portion is formed on the outer periphery, and an inner ring press-fitted into the small diameter step portion of the hub wheel. An inner member having a double row inner raceway facing
In the wheel bearing device comprising a double row rolling element accommodated in a freely rolling manner between the rolling surfaces of the inner member and the outer member,
A predetermined hardened layer is formed by induction hardening on the outer peripheral surface extending from the base on the inboard side of the wheel mounting flange in the hub wheel to the small-diameter stepped portion and the inner peripheral surface of the hub wheel corresponding thereto. A wheel bearing device that is characterized.   One inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery of the hub wheel, a predetermined hardened layer is formed on the inner rolling surface, and the hardened layer is formed on the small diameter step. 2. The wheel bearing device according to claim 1, wherein the inner ring is fixed in the axial direction by a caulking portion formed by being plastically deformed outwardly in a radial direction and stopped at an end portion of the portion.   The base portion of the wheel mounting flange and the radially inner portion corresponding to the inner rolling surface are formed in a hollow shape, a hardened layer is formed on the inner peripheral surface, and a non-hardened layer is provided between both hardened layers. The wheel bearing device according to claim 2.   The wheel according to any one of claims 1 to 3, wherein a predetermined hardened layer is formed at a corner extending from a base end portion of a side surface of the outboard in the wheel mounting flange to an outer peripheral surface of a brake pilot portion where a brake rotor is supported. Bearing device.   The wheel bearing device according to any one of claims 1 to 4, wherein serrations as torque transmitting means are formed on an inner periphery of the hub wheel, and a predetermined hardened layer is formed on a surface of the serration.

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