JP2002139060A - Wheel bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost wheel bearing device capable of suppressing deformation of its inner ring and excellent in the durability. SOLUTION: The wheel bearing device is composed of an outer ring having a mounting flange for mounting to a car body and equipped at the inside surface with raceways in two rows, a hub wheel 21 having a wheel mounting flange for mounting of a wheel and equipped at the peripheral surface with a first raceway, an inner ring 22 fitted on a minor diametric step part 28 of the hub wheel 21 and equipped at the periphery with a second raceway 29, and balls/ rollers in two rows interosed between the raceways of the outer ring, hub wheel 21, and inner ring 22, and is constructed so that the ends of the hub wheel 21 are tightened for consolidating them without possibility of separating, wherein the end formed on the hub wheel 21 before tightening consists of a cylindrical part 36 in hollow shape, and its wall thickness increases gradually toward the forefront.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel bearing device, and more particularly, to a wheel bearing device for rotatably supporting a wheel with respect to a vehicle suspension.

[0002]

2. Description of the Related Art As a wheel bearing device for rotatably supporting a wheel with respect to a suspension device of an automobile, for example, Japanese Patent Laid-Open No.
0-95203, JP-A-10-196661, JP-A-10-272903 and JP-A-11-1
There is one disclosed in Japanese Patent No. 29703. FIG. 6 shows a typical example of the wheel bearing device disclosed in Japanese Patent Application Laid-Open No. 10-272903.

This wheel bearing device comprises a hub wheel 1, an inner ring 2,
The rolling elements 3 in multiple rows and the outer ring 4 as an outer member are main components.

[0004] The hub wheel 1 has a track surface 5 on the outboard side formed on the outer peripheral surface thereof and a wheel (not shown).
Is provided. Hub bolts 7 for fixing the wheel disc are provided at equal intervals in the circumferential direction of the flange 6. The inner ring 2 is fitted to a small-diameter stepped portion 8 formed on the inboard side of the hub wheel 1, and the outer peripheral surface of the inner ring 2 is fixed to the inboard side raceway surface 9.
Are formed. The inner ring 2 is press-fitted with an appropriate interference to prevent creep. The track surface 5 located on the outboard side of the vehicle and the track surface 9 located on the inboard side of the vehicle constitute a double-row track surface.

The outer race 4 has a double row of raceways 10, 11 on its inner peripheral surface facing the raceways 5, 9 of the hub wheel 1 and the inner race 2.
And a flange 12 for attaching to a vehicle body. Double row rolling elements 3 are incorporated between the raceway surfaces 5 and 9 of the hub wheel 1 and the inner ring 2 and the double row raceway surfaces 10 and 11 of the outer ring 4. Seals 13 and 14 are mounted between the opening portions at both ends of the wheel bearing, that is, between the outer peripheral surface of the hub wheel 1 and the inner peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 4. Water and foreign substances are prevented from entering.

When the wheel bearing device is used for a driven wheel, the inner ring 2 extends from the small diameter step 8 of the hub wheel 1 in order to prevent the inner ring 2 pressed into the small diameter step 8 of the hub wheel 1 from falling off.
The cylindrical portion formed at the more protruding end portion is caulked outward in the diameter direction, and the inner ring 2 is fixed to the hub wheel 1 by the caulked portion 15 formed thereby. By tightening the cylindrical portion of the hub wheel 1, the bearing clearance is set to a predetermined value.

[0007]

By the way, in the above-mentioned conventional wheel bearing device, in order to fix the inner ring 2 to the hub wheel 1, the cylindrical portion formed at the end of the hub wheel 1 is plastically deformed and caulked. When the portion 15 is formed, the outer diameter of the inner ring 2 swells radially outward, and a non-negligible deformation occurs on the raceway surface 9 formed on the outer diameter surface of the inner ring 2, and the rolling elements 3 and the inner ring 2 come into contact with each other. Since the circumferential stress at the position becomes excessively large and the rolling fatigue life may decrease, the circumferential stress at the contact position is suppressed from increasing due to the caulking. Therefore, the inner ring 2 had to be larger than a predetermined value, and the inner ring 2 had to be increased in the axial direction on the inboard side.

On the other hand, as described above, the bearing clearance is set to a predetermined value by caulking the end of the hub wheel 1. However, if the caulking causes deformation of the inner ring 2, the bearing clearance is reduced. It may deviate from the predetermined value, making it difficult to obtain the expected bearing characteristics.

The inner ring 2 is made of expensive bearing steel, for example, high carbon chromium steel for bearings, which is specified in JIS G 4805.
Since high carbon steel such as UJ2 was used, there was a problem that the cost of the product was increased.

Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to provide an inexpensive wheel bearing device which suppresses deformation of an inner ring and has excellent durability. .

[0011]

As technical means for achieving the above object, a wheel bearing device according to the present invention has a vehicle body mounting flange to be mounted on a vehicle body, and has a double row raceway surface on an inner periphery. A hub ring having an outer member and a wheel mounting flange for mounting the wheel, a first raceway surface formed on the outer periphery, and a small-diameter stepped portion of the hub wheel, the second raceway surface being fitted on the outer periphery An end member extending from a small-diameter step portion of the hub wheel, comprising: an inner member formed of an inner ring formed; and a plurality of rows of rolling elements interposed between respective raceway surfaces of the outer member and the inner member. In the wheel bearing device in which they are integrally formed in a non-separable manner, the end of the hub wheel before the swaging forms a hollow cylindrical portion, and the thickness gradually increases toward the tip. (Claim 1).

[0012] In the wheel bearing device of the present invention, the end of the hub wheel before crimping forms a hollow cylindrical portion, and the thickness gradually increases toward the tip, so that it is pushed out by a punch at the beginning of machining. Since the wall thickness is increased, the axial dimension for plastically deforming the end of the hub wheel can be reduced, and the inner ring can be firmly fixed easily in a punch shape at an early stage.

[0013] In the present invention, the cylindrical portion formed at the end of the hub wheel before caulking as described in claim 2 is:
It is desirable that the outer diameter be slightly reduced toward the tip. In this way, when assembling the inner ring to the hub wheel, the work of pressing the inner ring into the hub wheel can be easily performed. In addition, as described in claim 3, it is desirable to round the corner of the end face of the cylindrical portion formed at the end of the hub wheel before caulking. With this configuration, it is possible to prevent the occurrence of defects such as burrs and cracks when caulking the cylindrical portion of the hub wheel.

Further, the wheel bearing device according to the present invention has a vehicle body mounting flange to be mounted on a vehicle body, an outer member having a double row of raceways on the inner periphery, a wheel mounting flange for mounting wheels, and an outer periphery. A hub ring having a first raceway surface formed thereon, and an inner member formed of an inner race fitted with a small-diameter stepped portion of the hub ring and having a second raceway surface formed on the outer periphery; and the outer member. A double-row rolling element interposed between the respective raceway surfaces of the inner member; a wheel bearing device in which end portions extending from the small-diameter step portion of the hub wheel are crimped to integrate them inseparably. The outer end surface of the caulked portion is formed of a first tapered surface whose thickness gradually increases from the deformation origin side to the outer diameter direction, and an angle formed between the first tapered surface and a plane along the radial direction. Is set in the range of 0 to 30 ° (claim 4).

In the wheel bearing device according to the present invention, the outer end surface of the caulked portion is formed of a first tapered surface whose thickness gradually increases from the deformation origin side in the outer radial direction, and the first tapered surface is formed. By setting the angle between the inner ring and the plane extending along the radial direction in the range of 0 to 30 °, it is possible to improve the withstand resistance of the inner ring and prevent deformation of the inner ring.

According to the present invention, the outer end surface of the caulked portion is formed as a second tapered surface from the first tapered surface to the outer peripheral edge, and the second tapered surface is formed. It is desirable to set the angle between the angle and the plane along the radial direction in the range of 45 to 50 °. In this way, an appropriate preload can be applied, and burrs do not occur in the crimping process.

In the present invention, the first tapered surface and the second tapered surface are connected to each other so as to be in contact with the tapered surfaces by a curved surface having a predetermined radius of curvature. This is desirable in that galling and burr during crimping can be prevented and an appropriate preload can be applied.

In the present invention, it is preferable that the chamfered portion formed at the inner diameter end of the inner ring has an arc shape, and that its axial and radial dimensions are approximately 1 mm. When fixing the inner ring to the hub wheel by making the shape of the chamfer at the inner diameter end of the inner ring into an arc shape having a radius of curvature of 1 to 2.5 mm and its axial and radial dimensions being approximately 1 mm. In addition, the caulking portion is prevented from pushing the inner ring outward in the diametrical direction, and deformation of the inner ring is minimized.

Further, an annular groove is formed at the outer diameter of the end of the hub wheel as described in claim 8, and the annular groove partially covers a chamfer formed at the inner diameter end of the inner ring. It is desirable to be provided as follows. With this configuration, it is possible to further suppress the caulking portion from pushing the inner race outward in the diameter direction.

In the present invention, the hub wheel is formed of carbon steel having a carbon content of 0.45 to 0.80 wt%, preferably 0.60 to 0.80 wt%, as described in claim 9. Form a surface hardened layer by induction hardening at the site,
Further, as described in claim 10, it is desirable that the inner ring is formed of carbon steel having a C content of 0.60 to 0.80 wt%, and is hardened and hardened to the core. For this reason, workability (forging) can be improved while maintaining the desired rolling fatigue life by the amount of carbon less than that of the high carbon steel.
Further, the surface hardness of the hub wheel is hardened by induction hardening at a predetermined portion, and the hardening of the inner wheel is hardened up to the core portion, thereby suppressing a decrease in hardness and improving the rolling fatigue life.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wheel bearing device according to the present invention will be described in detail below.

The main components of the wheel bearing device of the embodiment shown in FIG. 1 are a hub wheel 21, an inner ring 22, double rows of rolling elements 23, and an outer ring 24 as an outer member.

The hub wheel 21 has an outboard side (first) raceway surface 25 formed on the outer peripheral surface thereof and has a flange 26 for mounting a wheel (not shown). Hub bolts (not shown) for fixing the wheel disc are implanted at equal intervals in the circumferential direction of the flange 26. Further, the inner ring 22 is fitted into a small-diameter stepped portion 28 formed on the inboard side of the hub wheel 21,
A track surface 29 on the inboard side (second) is formed on the outer peripheral surface of No. 2. The inner ring 22 is press-fitted with an appropriate interference to prevent creep. A raceway surface 25 located on the outboard side of the vehicle and a raceway surface 29 located on the inboard side of the vehicle constitute a double-row raceway surface.

The outer race 24 has a double row of raceways 30, 31 facing the raceways 25, 29 of the hub wheel 21 and the inner race 22 on its inner peripheral surface, and has a flange 32 for mounting to the vehicle body. . Double-row rolling elements 23 are incorporated between raceway surfaces 25 and 29 of hub wheel 21 and inner ring 22 and double-row raceway surfaces 30 and 31 of outer ring 24. Seals 33 and 34 are attached between the opening portions at both ends of the wheel bearing, that is, between the outer peripheral surfaces of the hub wheel 21 and the inner ring 22 and the inner peripheral surface of the outer ring 24, so that the grease filled therein leaks from the outside and the outside. Water and foreign substances are prevented from entering.

When the wheel bearing device is for a driven wheel, the inner ring 22 extends from the small-diameter step portion 28 of the hub wheel 21 to prevent the inner ring 22 pressed into the small-diameter step portion 28 of the hub wheel 21 from falling off. The cylindrical portion formed at the more protruding end portion is caulked radially outward, and the caulked portion 3 formed thereby is formed.
5, the inner ring 22 is fixed to the hub wheel 21. By tightening the cylindrical portion of the hub wheel 21, the bearing clearance is set to a predetermined value.

The cylindrical portion formed at the end of the hub wheel 21 before the caulking and the small-diameter step portion 28 of the hub wheel 21
FIG. 2 shows the inner ring 22 press-fitted into the inner ring 22.

As described above, the hub wheel 2 before crimping is performed.
One end forms a hollow cylindrical portion 36. This cylindrical portion 36
Has a constant axial depth d ₁ , the thickness of which gradually increases towards the tip. The axial depth d ₁ of the cylindrical portion 36 is a dimension determined by the required performance of the product, and this depth d ₁
The larger is, the smaller the deformation of the inner ring 22 due to caulking outward in the diameter direction, but the caulking strength is slightly reduced. The cylindrical portion 36, when the difference between the outer radius and the inner radius at the bottom position of the cylindrical portion 36 has a root portion thickness D _1, the tip portion thickness D ₂ than the root portion thickness D ₁ increases As shown in FIG.

[0028] or the root portion thickness D ₁ also tip thickness D ₂ is the same than compared with the case that is small, the increased meat quantity to be spread by the punch machining initial wheel hub 21
The axial dimension for plastically deforming the cylindrical portion 36 can be reduced, and the inner ring 22 can be firmly fixed to the punch shape easily at an early stage.

The crimping of the cylindrical portion 36 of the hub wheel 21 is performed in the manner shown in FIGS.
First, as shown in FIG.
While being placed on the upper side, the inner ring 22 is fitted to the small-diameter step portion 28 of the hub wheel 21 to a predetermined position. That is, the inner ring 22 is pressed into the hub wheel 21 until the end surface on the outboard side of the inner ring 22 abuts against the end surface of the small-diameter step portion 28 of the hub wheel 21. Next, as shown in FIG. 3B, the crimping punch 38 is rotated while swinging with respect to the axis of the hub wheel 21, and in this state, the processing surface 39 located at the lower end of the crimping punch 38. Thus, a predetermined load is applied to the cylindrical portion 36 of the hub wheel 21. Then, as shown in FIG. 3C, the crimping punch 38 is finally lowered to the bottom dead center to form the crimping portion 35 at the end of the hub wheel 21.

As shown in FIG. 2, before crimping, the cylindrical portion 36 formed at the end of the hub wheel 21 is
The outer diameter is formed to be slightly smaller toward the tip. In other words, the outer diameter of the cylindrical portion 36 is 0.05-0.
The spigot part 40, which is about 25 mm smaller,
mm. In this way, when assembling the inner ring 22 to the hub wheel 21, the work of press-fitting the inner ring 22 into the hub wheel 21 can be easily performed, and the cost required for the press-fitting equipment can be reduced and the cost can be reduced. The same effect can be obtained by providing a large spigot of about 0.05 to 0.25 mm on the outboard side of the inner diameter of the inner ring 22 in the axial direction of about 5 to 12 mm.

Further, before caulking, the hub wheel 2
The corner 41 of the end face of the cylindrical portion 36 is rounded. In this way, it is possible to prevent the occurrence of defects such as burrs and cracks when caulking the cylindrical portion 36 of the hub wheel 21.

The hub wheel 21 has a C of 0.45 to 0.8.
It is formed of medium carbon steel of 0 wt%, preferably 0.60 to 0.80 wt%, and a surface hardened layer 42 is formed at a predetermined portion by induction hardening as shown in FIG. The inner race 22 is made of medium carbon steel with C of 0.60 to 0.80 wt%, and is hardened and hardened to the core. Therefore, JISG 4
SUJ2 specified in 805 (C is 0.95 to 1.1
The workability (forging) is improved by the amount of carbon which is smaller than that of high carbon steel such as 0 wt%.

The hub wheel 21 has a surface hardened layer 42 formed by induction hardening at a predetermined position, thereby improving the rolling fatigue life and preventing fretting on the fitting surface. Regarding the inner race 22, the raceway surface 29 is a place where the life is strict on the inboard side, so that quenching and hardening up to the core can suppress a decrease in hardness and improve the strength surface and the rolling fatigue life. C satisfies the strength, wear resistance and rolling fatigue life required for product functions, and the hub wheel 21 requires 0.45 wt% or more and the inner ring 22 requires 0.60 wt% or more, and 0.80 wt%. When the content is increased, the workability, machinability and toughness are reduced, so that the upper limit is set.

The hardened surface layer 42 of the hub wheel 21 is
1, the outer peripheral surface of the hub wheel 21 with which the seal lip of the seal 33 attached to the outboard side end of the outer ring 24 slides, that is, the small diameter step portion from the seal sliding contact portion via the raceway surface 25. It is formed in 28 areas.

When the respective portions of the surface hardened layer 42 are indicated by a to d, the a portion is a seal lip portion with which the seal lip of the seal 33 is in sliding contact, and therefore requires abrasion resistance. The part b is the raceway surface 25 on which the rolling element 23 rolls, and therefore requires a long life. The portion c is a portion that comes into contact with the inner ring 22 and d
Since the portion is a portion where the inner ring 22 is fitted to the hub wheel 21,
Creep resistance and fretting resistance are required. Since the portion e is the caulked portion 35, ductility is required.

The heat treatment for forming the surface hardened layer 42 is preferably induction hardening. The high-frequency heat treatment as the surface hardening treatment makes it possible to freely select the hardened layer 42 by effectively utilizing the characteristics of the induction heating, and to provide wear resistance and improve fatigue strength. Induction heating is a method in which electric energy is directly converted into heat energy in a metal using electromagnetic induction to generate heat, and high-frequency heat treatment using this method has many features. In particular, since local heating can be performed, the depth of the hardened layer can be freely selected, and control can be performed so as not to significantly affect a portion other than the hardened layer, so that the performance of the base material can be maintained. Therefore, the desired hardened layer 42 can be formed in the regions of the portions a to d, and the portion e can be left as an unquenched base material.

As shown in FIG. 2, a chamfered portion 43 is formed at the inner diameter end of the inner ring 22. The chamfered portion 43 connecting the inboard end surface of the inner race 22 and the inner diameter surface has an arc shape with a radius of curvature r _{1 of 1} to 2.5 mm. Further, the outer diameter of the cylindrical portion 36 of the hub wheel 21 has a depth n of about 0.5 mm,
An annular groove 44 having a radius of curvature r ₂ of about 5 to 10 mm is formed so as to partially cover the chamfered portion 43 of the inner ring 22. Since the chamfered portion 43 is formed at the end of the inner diameter of the inner ring 22 and the annular groove 44 is formed in the cylindrical portion 36 of the hub wheel 21, even if the cylindrical portion 36 of the hub wheel 21 is crimped, the inner ring 22 is formed. Of the inner ring 22 can be suppressed, and the deformation of the inner ring 22 can be minimized.

Here, if the radius of curvature r ₁ of the chamfered portion 43 of the inner ring 22 is smaller than ₁ mm, when a load is applied to the wheel bearing device during running while being mounted on an automobile, a root portion of the caulked portion 35 is formed. Stress concentration may cause damage such as cracks. Conversely, the radius of curvature r of the chamfered portion 43
_{When 1} is larger than 2.5 mm (including the case of the comparative example having the inclined surface 45 in FIG. 3), when the cylindrical portion 36 of the hub wheel 21 is swaged, the plastically deformed swaged portion 35 becomes larger than the inner ring 22. Since the chamfered portion 43 is pushed outward in the diametrical direction, the outer diameter of the inner ring 22 may be greatly deformed, and the bearing clearance may deviate from a predetermined value, making it difficult to obtain desired bearing characteristics. .

The chamfered portion 43 can be formed continuously with a radius of curvature such that the chamfered portion 43 contacts the inboard end surface and the inner diameter surface of the inner ring 22. From the difficult point, the axial and radial dimensions c ₁ and c ₂ of the chamfered portion 43 are set to the radius of curvature r.
It is desirable to set it slightly smaller than ₁ . By doing so, the chamfered portion 43 can be processed before the heat treatment of the inner ring 22, and the chamfering operation after the heat treatment can be omitted.

The crimped cylindrical portion 36 formed at the end of the hub wheel 21 shown in FIG. 2 is crimped by a crimping punch 38 in the manner shown in FIGS. 4 (a) to 4 (c). FIG. 5 shows the caulked portion 35 after the crimping.

The final shape of the caulked portion 35 is a first curved surface 46 having a radius of curvature r ₃ from the inner diameter side to the outer diameter side, and extends from the deformation origin X side to the outer diameter direction. It comprises a first tapered surface 47 having a gradually increasing wall thickness, a second curved surface 48 having a radius of curvature r _4, and a second tapered surface 49 forming an angle α ° with a plane along the radial direction. And inner ring 22
Having an axial length d ₄ to the vertex of the crimp portion 35 from the inboard side end face.

When the radius of curvature r ₃ of the first curved surface 46 is smaller than ₃ mm in the shape of the caulking portion 35, the caulking surface 39 of the caulking punch 38 is easily gnawed during caulking. This leads to a reduction in the life of the fastening punch 38. If the radius of curvature r ₃ is larger than 5 mm, the end of the cylindrical portion 36 of the hub wheel 21 must be widened by preforming before crimping. Must be pushed forward to the hub wheel 2
Burrs occur when the inner diameter of the cylindrical portion 1 and the caulking punch 38 are vigorously rubbed. Therefore, the radius of curvature r3 of the first curved surface 46 is preferably about ₃ to 5 mm.

It is clear that the first tapered surface 47 forms an angle β ° with respect to a plane extending in the radial direction, and when the angle β ° becomes a negative value, the resistance to removal of the inner ring 22 decreases. When the angle β ° is larger than 30 °,
As the force for expanding the inner ring 22 in the radial direction increases, the inner ring 22
Causes considerable deformation. As a result, the angle β ° of the first tapered surface 47 is preferably about 0 to 30 °.

The radius of curvature r _{4 of} the second curved surface 48 is 2 mm
If the diameter is smaller, the machined surface 39 of the crimping punch 38 is easily gnawed during the crimping process, and the life of the crimping punch 38 is reduced. If the radius of curvature r ₄ is larger than 10 mm, the force of pressing the inner ring 22 by the caulking portion 35 is weakened, and it is difficult to apply an appropriate preload. Therefore, the radius of curvature r ₄ of the second curved surface 48 is 2 to 10 mm
The degree is preferred.

If the angle α ° of the second tapered surface 49 is smaller than 45 °, the force of pressing the inner ring 22 by the caulking portion 35 is weakened, making it difficult to apply an appropriate preload. Also,
If the angle α ° is larger than 50 °, the end of the cylindrical portion 36 of the hub wheel 21 where the caulking portion 35 is about to expand toward the outer diameter side and the caulking punch 38 are vigorously rubbed, and burrs are generated. As a result, the angle α ° of the second tapered surface 49 becomes 4
It is preferably about 5 to 50 °.

However, when caulking so that the second curved surface 48 and the first tapered surface 47 do not contact each other, the radius of curvature r ₄ of the second curved surface 48 is set to be larger. It is also possible to omit the second tapered surface 49. In this case, preferably, the second curved surface 48 and the first curved surface 48
By forming a third curved surface having a radius of curvature of about 1 to 3 mm at the joint with the tapered surface 47, the burr generated near the joint is suppressed, and the life of the caulking punch 38 is reduced. Can be improved.

In the shape after caulking, the hub wheel 2
By leaving the annular groove 44 at the outer diameter of 1 and forming the chamfered portion 43 at the inner diameter end of the inner ring 22, the deformation of the inner ring 22 can be suppressed to a minimum.

[0048]

FIG. 3 shows an embodiment of the end of the hub wheel 21 before crimping and the form of the inner ring 22 shown in FIG. 2 as an embodiment. This is a comparative example. In the comparative example of FIG.
That is, a chamfered portion 43 'connecting the large inclined surface 45, the inboard side end surface, and the inner diameter surface is formed at the inner peripheral end. In addition,
Other shapes at the end of the hub wheel 21 are the same as those in FIG.

In the comparative example shown in FIG.
₂ is 58.8 mm, the inner diameter d ₃ is 28 mm, the axial dimension c ₁ ′ of the inclined surface 45 and the chamfered portion 43 is 3.5 mm, the radial dimension c ₂ ′ is 1.5 mm, and the angle θ of the inclined surface is 15 °. ,
An annular groove 44 having a radius of curvature r ₁ ′ of the chamfered portion 5 of 5 mm and an outer diameter of the cylindrical portion 36 of the hub wheel 21 having a depth n of about 0.5 mm and a radius of curvature r ₂ of about 7.8 mm is formed. When a part of the outer ring 22 was formed so as to cover the chamfered portion 43 ′ of the inner ring 22, the outer diameter of the inner ring 22 at a position 2 mm from the end face of the inner ring 22 expanded by about 35 μm by caulking.

On the other hand, in the embodiment shown in FIG.
2 has an outer diameter d ₂ of 58.8 mm, an inner diameter d ₃ of 28 mm, an axial dimension c ₁ of the chamfered portion 43 of ₁ mm, and a radial dimension c ₂ of 1
mm, the radius of curvature r ₁ is 1.5 mm, and the hub wheel 21
When an annular groove 44 having a depth n of about 0.5 mm and a radius of curvature r ₂ of about 7.8 mm is formed on the outer diameter of the cylindrical portion 36 so that a part of the annular groove 44 covers the chamfered portion 43 of the inner ring 22. The outer diameter of the inner ring 22 at a position 2 mm from the end face of the inner ring 22 expanded only by about 15 μm due to the caulking process.

In the embodiment of FIG. 2 and the comparative example of FIG. 3, the final shape of the caulked portion 35 after caulking has a radius of curvature r ₃ at the first curved surface 46 as shown in FIG. Is 3 mm, the angle β ° at the first tapered surface 47 is 5 °, and the second curved surface 4
8, the radius of curvature r ₄ is 4.2 mm, and the second tapered surface 49
Is 48.3 °, and the axial length d ₄ from the inboard end surface of the inner race 22 to the vertex of the caulking portion 35 is 5.
4 mm, and after crimping, leaving an annular groove 44 on the outer diameter of the hub wheel 21, and forming a chamfered portion 43 on the inner diameter end of the inner ring 22.
The deformation of the inner ring 22 was able to be suppressed to the minimum by forming.

[0052]

According to the present invention, since the deformation of the inner ring can be reduced to a negligible extent, the rolling fatigue life can be ensured, and the distance between the caulked portion and the contact point between the rolling element and the inner ring can be reduced. Because the distance can be shortened and the inner ring and hub ring can be designed compact in the axial direction,
When the product weight is reduced and it is used in an automobile, the fuel efficiency is easily improved, and the burden on the global environment can be reduced. Further, since the material cost and processing cost of the hub wheel and the inner ring are reduced, an inexpensive wheel bearing device can be provided.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing an embodiment of a wheel bearing device according to the present invention.

FIG. 2 is a half sectional view showing an end portion and an inner ring of a hub wheel before caulking in the embodiment of the present invention.

FIG. 3 is a half sectional view showing an end portion and an inner ring of a hub wheel before crimping in a comparative example with respect to the embodiment of FIG. 2;

FIGS. 4 (a) to 4 (c) are process diagrams for explaining a procedure for caulking an end portion of a hub wheel by rocking.

FIG. 5 is a half sectional view showing an end portion and an inner ring of the hub wheel after crimping in the embodiment of the present invention.

FIG. 6 is a half sectional view showing a conventional example of a wheel bearing device.

[Explanation of symbols]

 Reference Signs List 21 inner member (hub ring) 22 inner member (inner ring) 23 rolling element 24 outer member (outer ring) 25 first track surface 26 wheel mounting flange 28 small diameter step portion 29 second track surface 30, 31 track surface 32 vehicle body mounting flange 35 caulking part 36 cylindrical part 41 corner part 42 hardened surface layer 43 chamfered part 44 annular groove 47 first tapered surface 48 curved surface (second curved surface) 49 second tapered surface

Claims (10)

[Claims] An outer member having a vehicle body mounting flange mounted on a vehicle body and having a double row of raceway surfaces on an inner periphery, and a wheel mounting flange for mounting wheels, and a first raceway surface formed on an outer periphery. Between an inner member formed of an inner ring fitted with a hub ring and a small-diameter stepped portion of the hub wheel and having a second raceway surface formed on an outer periphery thereof, and a raceway surface of each of the outer member and the inner member. A double-row rolling element interposed in the hub wheel, the end portion extending from the small-diameter stepped portion of the hub wheel is swaged to integrate them inseparably, A wheel bearing device, wherein the end portion forms a hollow cylindrical portion, and the thickness of the cylindrical portion gradually increases toward the tip. 2. The method according to claim 1, wherein the cylindrical portion formed at the end of the hub wheel before caulking is formed so that its outer diameter becomes slightly smaller toward the tip. The wheel bearing device according to the above. 3. The wheel bearing device according to claim 1, wherein a corner of an end surface of a cylindrical portion formed at an end of the hub wheel before caulking is rounded. 4. An outer member having a vehicle body mounting flange to be mounted on a vehicle body and having a double row of raceway surfaces on an inner periphery and a wheel mounting flange for mounting wheels, and a first raceway surface formed on an outer periphery. Between an inner member formed of an inner ring fitted with a hub ring and a small-diameter stepped portion of the hub wheel and having a second raceway surface formed on an outer periphery thereof, and a raceway surface of each of the outer member and the inner member. In a wheel bearing device comprising a double-row rolling element interposed in, and forming a caulked portion by plastically deforming the end portion extending from the small-diameter step portion of the hub wheel, and integrally integrating them. The outer end surface of the caulked portion is formed by a first tapered surface whose thickness gradually increases from the deformation origin side to the outer diameter direction, and an angle formed by the first tapered surface and a plane along the radial direction is defined as an angle. 0 to
A wheel bearing device characterized by being set in a range of 30 °. 5. An outer end surface of the caulked portion is formed by a second tapered surface extending from the first tapered surface to an outer peripheral edge, and an angle formed by the second tapered surface and a plane along a radial direction. 45 to
The wheel bearing device according to claim 4, wherein the wheel bearing device is set in a range of 50 °. 6. The tapered surface according to claim 5, wherein the first tapered surface and the second tapered surface are connected to each other by a curved surface having a predetermined radius of curvature. The wheel bearing device according to the above. 7. A method according to claim 1, wherein the chamfered portion formed at the inner diameter end of the inner ring has an arc shape, and its axial and radial dimensions are substantially 1 mm. The wheel bearing device according to the above. 8. An annular groove is formed at an outer diameter of an end portion of the hub wheel, and the annular groove is provided so as to partially cover a chamfer formed at an inner diameter end portion of the inner ring. The wheel bearing device according to claim 7, wherein: 9. The method according to claim 9, wherein C is 0.45 to 0.80.
2. A surface hardened layer formed by induction hardening at a predetermined portion by using carbon steel of wt%.
A wheel bearing device according to any one of claims 1 to 8. 10. The inner ring having a C of 0.60 to 0.80.
The wheel bearing device according to any one of claims 1 to 9, wherein the wheel bearing device is formed of carbon steel of wt% and quenched and hardened to the core.