JP2004268645A - Rolling bearing unit for wheel supporting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a rotating side flange 15 from being deformed accompanying the fixing of a wheel 1 to the rotating side flange 15 by fastening a nut 10, and in addition, to prevent juddering from occurring at the time of braking by suppressing the shaking of a rotor 2 which is fixed to the rotating side flange 15. <P>SOLUTION: For this rolling bearing unit for wheel supporting, a quenchcured layer 30 is formed at a section which is located on the internal surface of a rotating side flange 15 and receives a force applied in the direction shown by arrow α accompanying the fastening of the nut 10. As a result, the deformation of the rotating side flange 15 can be suppressed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a wheel-supporting rolling bearing unit that supports a rotating body for braking such as a vehicle wheel and a rotor or a drum.
[0002]
[Prior art]
A wheel 1 constituting a wheel of an automobile and a rotor 2 serving as a rotating body for braking constituting a disc brake serving as a braking device are rotated by a knuckle 3 constituting a suspension device, for example, by a structure as shown in FIG. It is freely supported. That is, the outer ring 6 constituting the wheel supporting rolling bearing unit 5 to which the present invention is applied is fixed to the circular support hole 4 formed in the knuckle 3 by a plurality of bolts 7. On the other hand, the wheel 1 and the rotor 2 are mounted on a hub 8 which is an inner ring and a rotating raceway ring as described in the claims, which constitutes the rolling bearing unit 5 for supporting the wheel, and a plurality of studs 9 and nuts. 10 and fixed.
[0003]
Double rows of outer raceways 11a and 11b are formed on the inner peripheral surface of the outer race 6, and fixed-side flanges 12 are formed on the outer peripheral surface. Such an outer ring 6 is fixed to the knuckle 3 by connecting the fixed flange 12 to the knuckle 3 with the bolts 7.
[0004]
On the other hand, the hub 8 is formed by combining the hub body 13 and the inner ring 14. Of these, a portion of the outer peripheral surface of the hub body 13 is an outer end opening of the outer ring 6 (the term "outside in the axial direction" means a portion which is outward in the width direction when assembled to an automobile; 1, 3 and 5-8, which is the center in the width direction when assembled to an automobile, is referred to as "inward in the axial direction. The same applies throughout the present specification." The rotating side flange 15, which is the flange described in the claims, is formed in the portion described above. The wheel 1 and the rotor 2 are fixedly connected to one side surface (outside surface in the illustrated example) of the rotating flange 15 by the studs 9 and the nuts 10.
[0005]
On the outer peripheral surface of the intermediate portion of the hub main body 13, a portion of the outer raceway 11 a, 11 b facing the outer raceway 11 a on the outer side is provided with a first inner raceway 17 on the hub body 13. On the other hand, it is formed directly. Further, the inner ring 14 is externally fitted and fixed to a small-diameter stepped portion 18 formed on the outer peripheral surface of the inner end portion of the hub main body 13 to constitute the hub 8. The second inner raceway 19 formed on the outer peripheral surface of the inner race 14 faces the inner outer raceway 11b of the double row outer raceways 11a and 11b.
[0006]
Between these outer raceways 11a, 11b and the first and second inner raceways 17, 19, a plurality of balls 20, 20, each of which is a rolling element, are held by holders 21, 21, respectively. It is provided so that it can roll freely in the state. With this configuration, a double-row angular contact type ball bearing as a rear combination is formed, and the hub 8 is supported inside the outer ring 6 so as to be rotatable and capable of supporting a radial load and a thrust load. Seal rings 22a and 22b are provided between inner peripheral surfaces of both ends of the outer ring 6 and outer peripheral surfaces of an intermediate portion of the hub body 13 and an inner end of the inner ring 14, respectively. The interior space provided with 20, 20 is shielded from the outside. Further, the illustrated example is a wheel supporting rolling bearing unit 5 for driving wheels (rear wheels of FR and RR vehicles, front wheels of FF vehicles, and all wheels of 4WD vehicles). , A spline hole 23 is formed. The spline shaft 25 of the constant velocity joint 24 is inserted into the spline hole 23.
[0007]
When the above-described rolling bearing unit 5 for supporting a wheel is used, as shown in FIG. 8, the outer ring 6 is fixed to the knuckle 3 and the wheel 1 in which a tire (not shown) is combined with the rotating flange 15 of the hub body 13. And the rotor 2 is fixed. The rotor 2 is combined with a support and a caliper (not shown) fixed to the knuckle 3 to form a disc brake for braking. At the time of braking, a pair of pads provided so as to sandwich the rotor 2 is pressed against both side surfaces of the rotor 2 which are friction surfaces for braking. In the present specification, the friction surface for braking refers to both axial sides of the rotor when the rotating body for braking is a rotor, and the drum when the rotating body for braking is a drum. Of the inner circumference.
[0008]
Also, hardening and hardening of the main part of the hub body 13 constituting the hub 8 of the wheel supporting rolling bearing unit 5 as described above is conventionally known, for example, as described in Patent Documents 1 and 2. ing. In the case of the rolling bearing units for wheel support described in these Patent Documents 1 and 2, the portion of the hub body that extends from the inner surface base to the small-diameter step portion of the rotating flange of the hub body is quenched and hardened. In addition to improving the strength of the rotating flange against the moment load applied during traveling, the wear resistance and the rolling fatigue life of each part of the outer peripheral surface of the hub main body are improved.
[0009]
On the other hand, it is known that vibrations accompanied by unpleasant noise, often called judder, occur when braking a vehicle. Various causes are known as the cause of such vibration, such as uneven friction between the side surface of the rotor 2 and the pad lining, but the runout of the rotor 2 is also known to be a major cause. Have been. That is, although the side surface of the rotor 2 should be perpendicular to the center of rotation of the rotor 2, it is difficult to make the side surface completely perpendicular due to unavoidable manufacturing errors. As a result, it is unavoidable that the side surface of the rotor 2 swings in the direction of the rotation axis (the left-right direction in FIG. 8) when the vehicle is running. When such deflection (the amount of displacement in the left-right direction in FIG. 8) increases, the judder occurs when the linings of a pair of pads are pressed against both side surfaces of the rotor 2 for braking. Further, when a drum constituting a drum brake is fixed to the side surface of the rotating side flange 15 and the inner peripheral surface of the drum is not completely parallel to the rotation center of the drum, the shoe is attached to the inner peripheral surface. When pressed, vibration like a judder also occurs.
[0010]
In order to suppress the judder generated by such a cause, it is important to suppress (reduce) the axial runout (axial runout) of the side surface of the rotor 2 or the radial runout of the inner peripheral surface of the drum. Become. In order to suppress the run-out, it is important to improve the perpendicularity of the mounting surface 26 of the rotating flange 15 (the surface on which the rotor 2 is mounted) to the center of rotation of the hub body 13. For this reason, as described in Patent Documents 3 and 4, etc., after assembling the components of the rolling bearing unit for supporting a wheel, the mounting surface of the rotating flange is machined to obtain the mounting surface. There is known a technique for improving the squareness.
[0011]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-21858 [Patent Document 2]
JP 2002-87008 A [Patent Document 3]
US Pat. No. 6,071,180 [Patent Document 4]
US Pat. No. 6,364,426
[Problems to be solved by the invention]
It is considered that the generation of the judder can be considerably reduced by improving the perpendicularity of the mounting surface 26 by a technique as described in Patent Documents 3 and 4, and the like. However, even if the perpendicularity of the mounting surface 26 is improved by the technique described in Patent Documents 3 and 4, etc., the wheel 1 and the rotor 2 are supported and fixed to the mounting surface 26, When the mounting surface 26 is distorted, it is not always possible to sufficiently suppress the side surface of the rotor 2 from swaying in the axial direction, and the effect of preventing the occurrence of the judder is impaired.
[0013]
In order to prevent the mounting surface 26 from being distorted as the wheel 1 and the rotor 2 are supported and fixed to the mounting surface 26, the hardness of the rotating flange 15 provided with the mounting surface 26 should be increased. Can be considered. The technology of quenching and hardening a part of the rotating side flange 15 (the base end portion on the inner surface) is also described in Patent Documents 1 and 2, but the conventional technology described in each of Patent Documents 1 and 2 is not described. However, it does not merely quench and harden the base end portion of the inner surface of the rotating side flange 15, and does not take into account the prevention of deformation of a portion to which stress is applied when the wheel 1 and the rotor 2 are supported and fixed to the mounting surface 26. .
[0014]
On the other hand, when the mounting surface 26 is quenched and hardened in order to simply prevent deformation of a portion to which stress is applied when the wheel 1 and the rotor 2 are supported and fixed to the mounting surface 26, the toughness of the rotating flange 15 is secured. It becomes difficult to do. The reason for this is that, when the mounting surface 26 is quenched and hardened, the hardened layer formed on the mounting surface 26 and the seal ring 22a are prevented from abrasion caused by sliding and the fatigue strength against bending moment is improved. This is because the hardened hard layer formed on the inner surface base end of the rotating side flange 15 is close to or continuous with the object. As is well known, the hardened hardened layer has lower toughness and is more susceptible to crack damage than the unhardened (raw) portion. Therefore, it is not preferable to form a hardened hardened layer on both the inner and outer surfaces of the rotating flange 15.
The rolling bearing unit for supporting a wheel of the present invention has been invented in view of such circumstances.
[0015]
[Means for Solving the Problems]
The rolling bearing unit for supporting a wheel of the present invention includes an inner ring having a double-row inner raceway on the outer peripheral surface and a double-row outer ring on the inner peripheral surface, similarly to the above-described conventionally known rolling bearing unit for supporting a wheel. An outer ring having a raceway and being arranged concentrically with the inner ring around the inner ring, and a plurality of rolling elements provided between the inner raceways and the outer raceways, each of which is rotatably provided. Prepare.
Then, the rotating body for braking and the wheel are used in a state where the rotating body for braking and the wheel are coupled and fixed by a screw rod member to the side surface of a flange formed on the outer peripheral surface of the rotating raceway ring which rotates during use among the inner ring and the outer ring. You.
In particular, in the rolling bearing unit for supporting a wheel of the present invention, a portion of the flange that is located around the screw rod member and is pressed by a part of the wheel as the screw rod member is tightened. A hardened hardened layer is formed on at least a part of the portion overlapping in the axial direction of the screw rod member.
[0016]
[Action]
In the case of the rolling bearing unit for supporting a wheel of the present invention configured as described above, a portion pressed by a part of the wheel in accordance with the tightening of the screw rod member and a portion overlapping with respect to the axial direction of the screw rod member. Due to the presence of the hardened hardened layer formed on at least a part of them, the rotation side flange is less likely to be distorted with the tightening of the screw rod member. For this reason, the braking surface of the braking rotator supported and fixed to the rotating flange is less likely to oscillate, and the occurrence of judder during braking can be effectively prevented.
Further, since the hardened hardened layer is formed on the inner side of the rotating flange, the toughness of the rotating flange is ensured, and the rotating race including the rotating flange is less likely to be cracked. You can leave it.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1, 2, and 4. FIG. A plurality of (in general, four to six, in the case of a passenger car) mounting holes 16 are provided at a part of the rotating side flange 15 provided at a portion near the outer end of the outer peripheral surface of the hub body 13 at equal intervals in the circumferential direction. Has formed. Then, a portion of each stud 9 which is a screw rod member near the base end is fitted and fixed to each of the mounting holes 16. Each of these studs 9 has an outward flange-shaped flange portion 27 at the base end, a serration portion 28 at a portion near the base end of the middle portion, and a male screw portion 29 at the middle to distal ends. Each of such studs 9 is inserted into each of the mounting holes 16 from the inside of the rotary side flange 15 to the outside, with the male screw portion 29 being inserted first, and the serration portion 28 is press-fitted into the mounting hole 16. In a state where the flange portion 27 is in contact with the inner side surface of the rotation side flange 15, the flange portion 27 is fixed to the rotation side flange 15 in a state where rotation is prevented.
[0018]
In the case of this example, a hardened hardened layer 30 is formed over the entire circumference by a high-frequency hardening process in a portion near the inner diameter of the inner surface of the rotating side flange 15. The outer diameter D ₃₀ of the quench hardened layer 30 is sufficiently larger than the outer diameter of at quenching the cured layer to the described structure in Patent Documents 1 and 2 described above. Then, a load applied to the rotating side flange 15 due to the tightening of the nut 10 as described later can be supported by the hardened hardened layer 30. In the case of the present invention to this purpose, the outer diameter _{D 30,} is made larger than the diameter _{R 35} of the inscribed circle of the conical concave 35 formed on the wheel _{1 (D 30> R 35)} . Further, in the case of the present embodiment, the outer diameter D ₃₀ is provided at a plurality of locations on the inner side surface of the rotary flange 15 for accommodating the flange portion 27 by a counterbore 31 formed concentrically with the mounting holes 16. It is larger _{(D 30> R 31)} than the diameter _{R 31} of the inscribed circle of. The thickness (depth from the inner side) of the hardened hardened layer 30 is regulated from the aspect of preventing the deformation of the rotating side flange 15 while securing the toughness of the rotating side flange 15. In the case of a rolling bearing unit for supporting a wheel for a passenger car, the thickness is about 1 to 4 mm.
[0019]
The quench-hardened layer 30 is quench-hardened simultaneously with the portion of the rotation-side flange 15 extending from the inner surface base to the small diameter step. That is, also in the case of the present embodiment, the inner surface base, the first inner raceway 17 portion, and the small-diameter stepped portion 18 (see FIG. 8) on which the leading edge of the seal lip of the seal ring 22a is slidably contact are used to prevent wear or rolling. Hardens and hardens to ensure fatigue life. The heat treatment (quenching and tempering) for forming the hardened hardened layer 30 is performed simultaneously with each of these parts. In the case of this example, the quenching hardened layer 30 has a symmetrical shape in the circumferential direction, so that the heat treatment for quenching is performed while the heating coil is fixed and the hub main body 13 is centered on the center axis thereof. It can be done easily by rotating as In addition, it is possible to prevent the occurrence of unevenness due to unevenness in the distance between the heating coil and the surface of the hub body 13 to be quenched, thereby obtaining a hardened hardened layer 30 of good quality.
[0020]
The wheels 1 and the rotor 2 are fixedly connected to the rotating side flange 15 by the studs 9 fixed to the rotating side flange 15 as described above. Of these, the rotor 2 is externally fitted to a cylindrical surface portion 32 formed on a portion of the outer peripheral surface of the hub main body 13 adjacent to the outside of the rotating side flange 15 to perform positioning in the radial direction. In this state, the studs 9 are inserted into the through holes 33 formed in the rotor 2.
[0021]
The wheel 1 is made by pressing a steel plate, by casting a light alloy, or by forging a light alloy, and is aligned with each of the studs 9. A through hole 34 is formed in each part. The inner peripheral surface of each of the through holes 34 on the inner surface of the wheel 1 is formed by bending the steel plate or by forming a concave portion such as a thief in a part of the light alloy to form a cone-shaped cone. A concave surface 35 is formed. These conical concave surfaces 35 are used for guiding the studs 9 into the through holes 34 when the wheel 1 is mounted on the rotating side flange 15 and for facilitating the work of inserting the studs 9. In order to prevent loosening of the nut 10 which has been screwed into and further tightened, the nut 10 is provided with a spring action.
[0022]
To connect and fix the wheel 1 to the rotating flange 15 as described above, the first half of each of the studs 9 is inserted into each of the through holes 34, and a nut screwed into the male thread portion 29 of each of the studs 9. Tighten 10. As a result of the tightening of the nut 10, the peripheral portion of each of the conical concave surfaces 35 on the inner surface of the wheel 1 comes into contact with the outer surface of the portion closer to the inner diameter of the rotor 2 as shown by arrows α and α in FIG. The part is strongly pressed inward in the axial direction. A chain line γ in FIG. 2 indicates a portion where the peripheral portion of each of the conical concave surfaces 35 presses the outer surface of the rotary side flange 15 (the inner peripheral edge of the range) as indicated by the arrows α and α. I have. On the other hand, the flange portion 27 strongly presses a part of the rotary side flange 15 outward in the axial direction as shown by an arrow β in FIG. The position at which the flange 27 presses a part of the rotating flange 15 is around the mounting hole 16, but the arrow β is shown at the center where the force based on the flange 17 acts. ing.
[0023]
Due to the forces acting in the opposite directions indicated by the arrows α and β, a force acting in a direction to bend these peripheral portions around the mounting holes 16 at a part of the rotating flange 15 acts. When the peripheral portion of each of the mounting holes 16 of the rotary side flange 15 is deformed by this force, both side surfaces of the rotor 2 fixedly connected to the rotary side flange 15 swing in the axial direction with the rotation of the hub body 13. As a result, judder as described above occurs. On the other hand, in the case of the present example, a part of the force acting in the direction indicated by the arrows α and α from the peripheral portion of each of the conical concave surfaces 35 is supported by the quench hardened layer 30 portion. The portion where the quench hardened layer 30 is formed has high hardness and is not easily deformed by an external force. Therefore, most of the forces acting in the directions indicated by the arrows α and α correspond to the quench hardened layer 30 It will be supported by. That is, in the case of the present example, the part where the force acts in the directions of the arrows α and α and a part of the part that overlaps in the axial direction of each of the studs 9 (the part closer to the inner diameter of the rotating flange 15) The quenching hardened layer 30 is formed.
[0024]
With this configuration, the rest of the forces acting in the directions of the arrows α and α except for the part facing the quench hardened layer 30 does not form the quench hardened layer (raw Act on relatively soft parts). When a force acts only on the soft part, the soft part is deformed, which leads to the generation of the judder. In the case of this example, not only the soft part but also the hardened hardened layer 30 part Also at the same time. Then, the quench hardened layer 30 stretches against the above-mentioned force, thereby reducing the force acting on the above-mentioned soft part and preventing the soft part from being deformed. As a result, deformation of the rotation flange 15 around the mounting holes 16 is suppressed, and the occurrence of judder can be prevented.
[0025]
The hardened hardened layer 30 is provided on the same side as the hardened hardened layer provided at the base of the inner side surface of the rotating flange 15 in order to prevent abrasion and ensure bending rigidity. Therefore, a (raw) portion that has not been hardened and hardened can be sufficiently left on the rotating side flange 15. As a result, the toughness of the rotating flange 15 is sufficiently ensured, and even if an impact load is applied to the hub body 13, it is possible to effectively prevent the rotating flange 15 from being damaged such as a crack. In addition, when the hub body 13 is quenched and hardened, it is inevitable that deformation occurs due to the heat treatment. If the mounting surface 26, which is the outer surface of the rotary flange 15, is distorted due to the heat treatment deformation, it causes the judder. On the other hand, in the case of the present example, the mounting surface 26 is not quenched and hardened (the mounting surface 26 is still relatively soft). After the hub body 13 is subjected to the heat treatment, the mounting surface 26 can be easily subjected to finishing by a lathe or the like. For this reason, it is possible to obtain a low-cost wheel-supporting rolling bearing unit in which the axial runout of the mounting surface 26 due to the rotation of the hub body 13 is slightly suppressed (good runout accuracy).
[0026]
Next, FIGS. 3 and 4 show a second example of the embodiment of the present invention corresponding to claims 1, 2 and 5. FIG. In the case of this example, the hardened hardened layer 30a is formed at a position surrounding the entire circumference of the stud 9 which is a screw rod member. For this reason, in the case of the present example, the peripheral edge portion of each conical concave surface 35 pressing the outer surface of the rotating side flange 15 (the inner peripheral edge of the range) indicated by the chain line γ extends over the entire circumference. Can be backed up.
[0027]
In the case of such an example, the operation of forming the hardened hardened layer 30a is troublesome, but the effect of suppressing the deformation of the rotating side flange 15 and preventing the occurrence of judder during braking is as described above. It becomes better than the case of the first example. Since the configuration and operation of the other parts are the same as those of the first example described above, illustration and description of the same parts will be omitted.
[0028]
Next, FIGS. 5 and 6 show a third example of the embodiment of the present invention corresponding to claims 1, 3 and 5. FIG. In the case of this example, a plurality of (in the case of a passenger car, generally 4 to 6) screw holes 36 are formed in a part of the rotating side flange 15 formed on the outer peripheral surface of the hub body 13 in the circumferential direction. They are formed at equal intervals. A male screw portion 38 formed at the tip of each bolt 37, which is a screw rod member, is screwed into each of the screw holes 36, and further tightened.
[0029]
In the case of the present embodiment, a hardened hardened layer 30b is formed on the entire inner surface of the rotating flange 15 over the entire surface. The reason for forming the hardened hardened layer 30b over such a wide range is that, in the case of the structure of the present embodiment, the threaded rod member is the stud 9 as shown in FIGS. This is because a large bending stress is applied to the rotating side flange 15 in accordance with the tightening of the bolts 37 in comparison with the above. This will be described below.
[0030]
The bending stress for deforming the rotating side flange 15 is caused by the force applied to the threaded portion between the male screw portion 38 of each bolt 37 and each screw hole 36 in the direction of arrow β in FIG. 6 are generated from the peripheral edge of the conical concave surface 35 formed on the side surface via the rotor 2 and the arrow α in FIG. The magnitude of the bending stress increases in proportion to the distance between the points of action of the forces in the two directions. If the structure shown in FIGS. 1-2 described above, the distance L ₀ between the point of action, whereas a radial distance between the periphery of the flange portion 27 and the conical concave 35, the present embodiment case, the distance L ₁ between the working point will radial distance between the inner peripheral edge of the engagement portion and the conical concave 35. As apparent from the comparison between the distance L ₁ of the distance L ₀ and 6 in Figure 1, in the case of this example, a large distance L ₁ between the working point (L _{1> L 0),} the rotation-side Bending stress for deforming the flange 15 increases. Therefore, as described above, the hardened hardened layer 30b is formed over a wide range to prevent the rotation side flange 15 from being deformed.
[0031]
In the case where the hardened hardened layer 30b is formed over a wide range as in this example, the hardness of the hardened hardened layer 30b is excessively increased, and as a result, the followability of the screw holes 36 is deteriorated. Then, the adaptability between the screw hole 36 and the male screw portion 38 of each bolt 37 is deteriorated. Then, an excessive stress is generated in a part of the male screw part 38 of each of the bolts 37 or each of the screw holes 36, and the durability of the parts may be impaired. Therefore, in the case of this example, the hardness of the hardened hardened layer 30b is suppressed to about Hv400 to 500. However, even in this case, the hardness of the inner surface base end of the rotating side flange 15 which is continuous with the inner diameter side of the quench hardened layer 30b and slidably contacts the leading edge of the seal lip (see FIG. 8) of the seal ring 22a. Is about Hv560-800. The reason for this is to secure the bending strength of the rotating side flange 15 and the wear resistance of the portion. In order to make the hardness of each part different as described above, after tempering the inner side surface of the rotating side flange 15 including its base end, a tempering process (tempering) performed on the hardened hardened layer 30b portion is performed. (Temperature) is made higher than the temperature of the tempering process performed on the portion continuous to the inner diameter side.
[0032]
Next, FIG. 7 shows a fourth example of the embodiment of the present invention corresponding to claims 1, 3, and 4. In the case of the present example, similarly to the case of the above-described third example, a plurality of screw holes 36 formed in a part of the rotating side flange 15 are formed at the tip end of each bolt 37 which is a screw rod member. The external thread 38 is screwed and tightened. However, in the case of the present example, the hardened hardened layer 30c is formed only in the radially inner side of the bolt 37 in the radial direction of the rotating side flange 15 as in the case of the first example described above. are doing.
[0033]
In the case of this example, the effect of preventing the rotation-side flange 15 from being deformed due to the tightening of the bolt 37 is slightly inferior to the case of the third example described above. Processing of the hardened layer 30c is facilitated. The configuration and operation of the other parts are the same as those of the above-described third example or the first example.
[0034]
In each of the illustrated examples, the present invention is applied to a structure in which a hub serving as an inner ring rotates on the inner diameter side of an outer ring supported and fixed to a suspension device in a wheel supporting rolling bearing unit for driving wheels. It was shown about. However, the present invention is not limited to driving wheels, and is also applied to wheel supporting rolling bearing units for driven wheels (front wheels of FR and RR vehicles, rear wheels of FF vehicles). And among the wheel bearing rolling bearing units for the driven wheels, the inner ring rotating type is, of course, the outer ring hub that rotatably supports the hub as the outer ring around the inner ring that does not rotate while being supported by the suspension device. The present invention can also be applied to a rolling bearing unit for supporting a wheel of a type.
[0035]
【The invention's effect】
Since the rolling bearing unit for supporting a wheel of the present invention is configured and operates as described above, the flange is effectively prevented from being deformed as the wheel is fixed to the flange provided on the outer peripheral surface of the hub. it can. In addition, it is possible to prevent the rotation of the braking rotary body supported and fixed to the flange, and to sufficiently suppress unpleasant noise and vibration generated during braking.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a first example of an embodiment of the present invention and corresponding to a portion A in FIG. 8;
FIG. 2 is a view of the rotating side flange and stud taken out and viewed from the right in FIG. 1;
FIG. 3 is a sectional view showing a second example of the embodiment of the present invention and corresponding to a portion A in FIG. 8;
FIG. 4 is a diagram showing only the rotation-side flange taken out and viewed from the right side in FIG. 3;
FIG. 5 is a sectional view showing a third example of the embodiment of the present invention in a state where the third example is assembled to a suspension device.
FIG. 6 is an enlarged view of a portion B in FIG. 5;
FIG. 7 is a view similar to FIG. 6, showing a fourth example of the embodiment of the present invention;
FIG. 8 is a cross-sectional view showing an example of an assembled state of a rolling bearing unit for supporting a wheel, which is an object of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wheel 2 Rotor 3 Knuckle 4 Support hole 5 Rolling bearing unit 6 for wheel support Outer ring 7 Bolt 8 Hub 9 Stud 10 Nut 11a, 11b Outer ring track 12 Fixed side flange 13 Hub body 14 Inner ring 15 Rotation side flange 16 Mounting hole 17 First Inner raceway 18 small diameter step 19 second inner raceway 20 ball 21 retainer 22a, 22b seal ring 23 spline hole 24 constant velocity joint 25 spline shaft 26 mounting surface 27 flange 28 serration 29 external thread 30, 30a, 30b , 30c Hardened hardening layer 31 Counterbore 32 Cylindrical surface 33 Through hole 34 Through hole 35 Conical concave surface 36 Screw hole 37 Bolt 38 Male thread

Claims (5)

An inner ring having a double-row inner raceway on the outer peripheral surface, an outer race having a double-row outer raceway on the inner peripheral surface and arranged concentrically with the inner race around the inner race, the inner raceways and the outer races A plurality of rolling elements are provided between the tracks, each of which is provided so as to freely roll, and the side faces of a flange formed on an outer circumferential surface of a rotating raceway ring that rotates during use among the inner ring and the outer ring. In a wheel supporting rolling bearing unit used in a state where a rotating body for braking and a wheel are coupled and fixed by a screw rod member, the screw rod member is located around the screw rod member among the flanges. A quenched and hardened layer formed on at least a part of a part pressed by a part of the wheel with the tightening of the member and a part overlapping in the axial direction of the threaded rod member, for a wheel support. Rolling bearing unit. A stud in which a screw rod member has a base end portion press-fitted and fixed in a mounting hole formed in a flange, and an intermediate portion or a tip portion protrudes from an outer surface of the flange and is inserted into a through hole of a wheel. By tightening a nut screwed to a portion protruding from the outer surface of the wheel at the tip of the stud, the peripheral portion of the through hole is formed on the outer surface of the flange on a part of the inner surface of the wheel. The quenched and hardened layer is formed on a part of the inner surface of the flange opposite to a part pressed by a peripheral part of the through hole on a part of the inner side surface of the flange. Rolling bearing unit for wheel support. The screw rod member is a bolt, and this bolt is inserted into a through hole formed in the wheel, and its tip is screwed into a screw hole formed in the flange and further tightened, so that a part of the inner surface of the wheel is formed. The peripheral portion of the through hole is pressed against a part of the outer surface of the flange, and a part of the inner surface of the flange is quenched into a portion opposite to the portion pressed by the peripheral portion of the through hole. The rolling bearing unit for wheel support according to claim 1, wherein a hardened layer is formed. The rolling bearing unit for wheel support according to any one of claims 1 to 3, wherein the quench hardened layer is formed only in a portion on the inner diameter side of the center of the threaded rod member in the radial direction of the flange. The wheel bearing rolling bearing unit according to any one of claims 1 to 3, wherein the hardened hardened layer is formed at a position surrounding the entire circumference of the screw rod member.

Images