JP7754738B2 - Wheel bearing device - Google Patents

Description

The present invention relates to a wheel bearing device.

Wheel bearing devices that support the wheels of automobiles and other vehicles so that they can rotate freely are known. Some wheel bearing devices have a wheel pilot portion formed at the end of the hub axle that guides the inner diameter surface of the wheel.

For example, in the wheel bearing device disclosed in Patent Document 1, a wheel pilot portion is formed on the hub wheel that extends outboard beyond the wheel mounting flange and guides the inner diameter surface of the wheel.

In addition, in the wheel bearing device disclosed in Patent Document 1, recesses that retain the forged surface and protrusions that have a machined surface are formed alternately on the outer peripheral surface of the wheel pilot portion. This allows for weight reduction without reducing the rigidity of the hub wheel.

Patent No. 4844967

As with conventional technology, when protrusions and recesses are provided for the purpose of weight reduction, their positions are not specified, and they are positioned at any position on the outer peripheral surface of the pilot. However, wheel bearing devices have had the problem of the pilot portion of the hub wheel becoming stuck to the wheel or brake rotor due to dirt, rust, etc., depending on the usage environment and changes over time. When sticking occurs, the stuck portions are separated by inserting a tool into the recess formed on the outer peripheral surface of the pilot portion, between the pilot portion of the hub wheel, the wheel, and the brake rotor.

If the recess and the insertion hole for inserting the hub bolt in the wheel mounting flange are close to each other, the hub bolt and the tool may come into contact when inserting the tool into the recess with the hub bolt installed, making it difficult to separate the stuck parts.
Furthermore, if an attempt is made to forcibly separate a stuck wheel and brake rotor, the pilot part of the hub wheel may be damaged with a tool, etc., which may cause interference during reassembly or debris generated from the damaged part may get into the mounting surface of the wheel and brake rotor, causing the installation to lose its perpendicularity.
If the wheels lose their perpendicularity, resistance will occur when driving in a straight line, which may cause uneven tire wear.

The present invention was made in light of the above circumstances, and aims to provide a wheel bearing device that reduces the overall weight of the hub wheel while making it easier to insert a tool between the pilot part of the hub wheel and the wheel and brake rotor, thereby preventing the hub wheel from becoming dirty or rusting and extending its service life.

That is, an outer member having a double-row outer raceway surface formed on its inner periphery;
an inner member comprising a hub ring having an integral wheel mounting flange on the outboard side and having a cylindrical small diameter stepped portion formed on its outer periphery extending in the axial direction, and at least one inner ring press-fitted into the small diameter stepped portion of the hub ring, the inner member having a double row inner raceway surface formed on its outer periphery opposite the double row outer raceway surface;
a double row of rolling elements rollably accommodated between the rolling surfaces,
the hub wheel has a wheel pilot portion that extends outboard of the wheel mounting flange and guides the inner diameter surface of the wheel, and a recess having a depth of 1 to 3 mm is formed on the outer peripheral surface of the wheel pilot portion ,
The recesses are arranged asymmetrically about the axial direction,
The wheel mounting flange is provided with a lightening hole for adjusting the center of gravity of the hub wheel.

This invention reduces the overall weight of the hub wheel while making it easier to insert a tool between the pilot part of the hub wheel and the wheel and brake rotor, making it possible to separate the hub wheel, wheel, and brake rotor even if rust forms between them and they become stuck.

1 is a side cross-sectional view showing a wheel bearing device. FIG. 2 is a front view showing a wheel pilot portion of the hub wheel. FIG. 10 is a front view showing a wheel pilot portion of a hub wheel according to another embodiment. FIG. 4 is a partially enlarged front view showing a recess in the wheel pilot portion. FIG. 10 is a front view showing a wheel pilot portion of a hub wheel according to another embodiment. FIG. 10 is a front view showing a wheel pilot portion of a hub wheel according to another embodiment. FIG. 10 is a front view showing a wheel pilot portion of a hub wheel according to another embodiment.

The following describes an embodiment of the present invention with reference to the accompanying drawings.

[Wheel bearing device]
A wheel bearing device 1 shown in FIG. 1 is one embodiment of a wheel bearing device according to the present invention, and is used to rotatably support a wheel in a suspension system of a vehicle such as an automobile.

The wheel bearing device 1 has a configuration known as the third generation, and includes an outer ring 2 as the outer member, a hub ring 3 and an inner ring 4 as the inner members, two rolling rows of inner balls 5 and outer balls 6, a magnetic encoder 11, and a sensor holder 12.

In the following description, the axial direction refers to the direction along the rotational axis X of the wheel support bearing device 1. Additionally, the inner side refers to one side in the axial direction, which is the side facing the vehicle body when the wheel support bearing device 1 is attached to the vehicle body, and the outer side refers to the other side in the axial direction, which is the side facing the wheel when the wheel support bearing device 1 is attached to the vehicle body.

The inner end of the outer ring 2, which serves as the outer member, is formed with an inner opening 2a into which a sensor holder 12 can fit. The outer end of the outer ring 2 is formed with an outer opening 2b into which an outer seal member 9 can fit. The annular space S formed by the outer ring 2 and the hub wheel 3 is sealed by fitting the sensor holder 12 into the inner opening 2a, which is the opening at one axial end of the annular space S, and fitting the outer seal member 9 into the outer opening 2b, which is the opening at the other axial end of the annular space S.

The inner peripheral surface of the outer ring 2 is formed with an inner-side outer raceway surface 2c and an outer-side outer raceway surface 2d. A vehicle body mounting flange 2e is integrally formed with the outer peripheral surface of the outer ring 2 for mounting the outer ring 2 to a vehicle body member. The vehicle body mounting flange 2e is provided with bolt holes 2g into which fastening members (here, bolts) are inserted to fasten the vehicle body member and the outer ring 2. The outer ring 2 is located on the outer diameter side of the hub ring 3 and inner ring 4.

The inner end of the hub wheel 3, which serves as the inner member, has a small-diameter step 3a formed on its outer circumferential surface, which is smaller in diameter than the outer end. A wheel mounting flange 3b for mounting a wheel is integrally formed at the outer end of the hub wheel 3. The wheel mounting flange 3b has multiple bolt holes 3f formed in it. Hub bolts 3e for fastening the hub wheel 3 to a wheel or brake component are press-fitted into the bolt holes 3f.

The outer peripheral surface of the hub wheel 3 is provided with an outer inner raceway 3c that faces the outer outer raceway 2d of the outer ring 2. In other words, the inner raceway 3c is formed by the hub wheel 3 on the outer side of the inner member. A seal land portion 3d of the outer seal member 9 is formed on the base side of the wheel mounting flange 3b of the hub wheel 3.

The outer seal member 9 has a core 91 that fits into the outer opening 2b of the outer ring 2, and a seal member 92 that is integrally joined to the core 91. The seal member 92 is in sliding contact with the seal land portion 3d of the hub wheel 3.

An inner ring 4 is mounted on the small diameter step 3a of the hub ring 3. The inner ring 4 is fixed to the small diameter step 3a of the hub ring 3 by press fitting and crimping. The inner ring 4 applies preload to the inner ball row 5 and outer ball row 6, which are the rolling rows. The outer peripheral surface of the inner ring 4 is provided with an inner inner raceway surface 4a that faces the inner outer raceway surface 2c of the outer ring 2. In other words, the inner ring 4 forms the inner raceway surface 4a on the inner side of the inner member.

The inner ring 4, which is the inner member, has an inner end face 4b at its inner end. A crimped portion 3h is formed at the inner end of the hub ring 3, crimped to the inner end face 4b of the inner ring 4.

The inner ball row 5 and outer ball row 6, which are rolling rows, are composed of a plurality of balls 7, which serve as rolling elements, held in a cage 8. The inner ball row 5 is rollably sandwiched between the inner raceway surface 4a of the inner ring 4 and the inner outer raceway surface 2c of the outer ring 2. The outer ball row 6 is rollably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer outer raceway surface 2d of the outer ring 2. In other words, the inner ball row 5 and outer ball row 6 are rollably housed between the raceway surfaces of the outer member and the inner member. The outer ring 2 rotatably supports the hub ring 3 and inner ring 4 via the inner ball row 5 and outer ball row 6.

In the wheel bearing device 1, a double-row angular contact ball bearing is formed by the outer ring 2, which is the outer member, the hub ring 3 and inner ring 4, which are the inner members, the inner ball row 5, and the outer ball row 6. Note that the wheel bearing device 1 may also be formed as a double-row tapered roller bearing instead of a double-row angular contact ball bearing.

Next, we will explain the wheel pilot portion 3g provided on the outer end surface of the hub wheel 3.

As shown in Figures 1 and 2, the wheel pilot portion 3g is formed by extending from the outer end face of the wheel mounting flange 3b of the hub wheel 3 toward the outer side along the axial direction, and is a portion that guides the inner diameter surface of the wheel or brake component.
It is desirable that the wheel pilot portion 3g have a smooth inner surface to guide the inner diameter surface of the wheel or brake component. For example, if the inner surface of the wheel pilot portion 3g is damaged during assembly, debris from the damage may enter the inner diameter surface of the wheel or brake component, causing a loss of perpendicularity in the installation. If the perpendicularity in the installation is lost, interference occurs between the inner surface of the wheel pilot portion 3g and the inner diameter surface of the wheel or brake component, resulting in abnormal noise.

The wheel pilot portion 3g is formed in a cylindrical shape. That is, the circumferential surface of the wheel pilot portion 3g is formed so that it is parallel to the rotation axis X. However, the wheel pilot portion 3g may also be formed so that its circumferential surface is inclined with respect to the rotation axis X.

The wheel pilot portion 3g is formed in a cylindrical shape, and its outer peripheral surface is provided with a recess 3h that is arc-shaped in cross section.

The recess 3h extends from the outer end surface of the outer peripheral surface of the wheel pilot portion 3g to the base end 3i of the wheel mounting flange 3b. As shown in FIG. 1, the base end 3i is rounded. The radius of the base end 3i, i.e., the radius of the rising portion between the wheel mounting flange 3b and the wheel pilot portion 3g, is set to 2 mm to 5 mm. By forming the recess 3h in this manner, even if muddy water accumulates in the space between the outer peripheral surface of the wheel pilot portion 3g and the inner diameter surface of the wheel or brake component, the radius of a predetermined value or greater makes it easier for the muddy water to be discharged to the outside through the wheel mounting flange 3b.
Furthermore, by setting the R dimension of the raised portion between the wheel mounting flange 3b and the wheel pilot portion 3g to 5 mm or less, a clearance can be secured between the straight and curved inner diameter portions of the brake components, and the engagement allowance between the tool and the inner diameter portion can be maintained appropriately.

As shown in Figure 4, the recess 3h is formed in an arc-shaped cross section. However, the cross-sectional shape of the recess 3h is not limited to an arc-shaped cross section; for example, it may be in the shape of a portion of an ellipse.

Furthermore, it is preferable that the radius of the recess 3h be 6 mm or greater. In other words, the radius is configured to be large enough to allow a tool to be guided into the space formed between the recess 3h and the inner diameter surface of the wheel or brake component.

In addition, chamfers are provided at the points where both circumferential ends of the recess 3h meet the outer peripheral surface, i.e., the outer peripheral edge of the recess 3h. The chamfers are machined into a curved shape, preventing damage to mating components at the contact points between the outer peripheral surface of the recess 3h and the inner diameter surface of the wheel or brake component.

The recess 3h is formed to a depth d of 1 to 3 mm from the outermost surface of the outer periphery. Here, depth d is the length from the innermost portion of the arc-shaped recess 3h to the outer periphery in a cross-sectional view. This configuration makes it possible to guide a tool into the space formed between the recess 3h and the inner diameter surface of the wheel or brake component, and also ensures the rigidity of the wheel pilot portion 3g.

Furthermore, the recesses 3h are arranged at equal intervals along the circumferential direction when viewed in the axial direction. That is, the recesses 3h are evenly spaced on a concentric circle centered on the rotation axis X when viewed from the front. In FIG. 2, five recesses 3h are provided on the outer peripheral surface of the wheel pilot portion 3g, and the ratio of the total circumferential length of the recesses 3h to the outer peripheral length of the wheel pilot portion 3g is 35 to 75%. If the ratio of the total circumferential length of the recesses 3h to the outer peripheral length of the wheel pilot portion 3g is less than 35%, the options for guiding a tool into the space formed between the recesses 3h and the inner diameter surface of the wheel or brake component are narrowed. On the other hand, if the ratio of the total circumferential length of the recesses 3h to the outer peripheral length of the wheel pilot portion 3g is greater than 75%, the recesses 3h will not be able to function as a guide for the wheel or brake component, causing rattle or making it difficult to ensure perpendicularity.
By configuring the ratio of the total circumferential length of the recess 3h to the circumferential length of the wheel pilot portion 3g to be 35 to 75%, the weight of the wheel pilot portion 3g can be reduced, and further, the wheel pilot portion 3g can serve as a guide for the wheel or brake parts.

As shown in Figure 3, the recesses 3h can also be arranged with their circumferential phases shifted from those of the bolt holes 3f when viewed in the axial direction. This difference in phase ensures that the recesses 3h and bolt holes 3f are not located on the same radius. In Figure 3, the recesses 3h are arranged on a radius rotated by an angle b from the radius on which the bolt holes 3f are located. This configuration makes it possible to guide a tool into the space formed between the recesses 3h and the inner diameter surface of the wheel or brake component without the tool coming into contact with the hub bolts 3e. Note that, in this embodiment, the number of hub bolts 3e and the number of recesses 3h are arranged so that they are the same, but this is not limited to this.

Furthermore, as shown in Figure 5, the recesses 3h can be arranged asymmetrically in the axial view. In other words, the recesses 3h can be arranged so that there are locations where they are not equally spaced along the circumferential direction. In Figure 5, three recesses 3h are provided on the upper semicircular side, and two recesses 3h are provided on the lower semicircular side. This shifts the center of gravity of the wheel pilot portion 3g downward, causing uneven locations of sticking.
If the recesses 3h are uniformly formed in the wheel pilot portion 3g, the recesses 3h may not be located in the locations on the outer peripheral surface of the wheel pilot portion 3g where rust will occur. This can be solved by shortening the intervals between adjacent recesses 3h and increasing the number of recesses 3h, but this increases the time required to machine the recesses 3h, impairing workability.
Therefore, the recesses 3h can be arranged unevenly, and a tool can be inserted on the side opposite to the portion with a large adhesion area to remove the adhesion by lever principle. In other words, a tool can be inserted on the side where the intervals between the recesses 3h are narrower than the side where the intervals between the recesses 3h are wide, and the adhesion can be removed by lever principle.

Also, as shown in Figure 6, the recesses 3h can be arranged asymmetrically when viewed in the axial direction, and lightening holes 3j can be provided in the lower half of the wheel mounting flange 3b. In Figure 6, four recesses 3h are provided on the upper semicircular side, and two recesses 3h are provided on the lower semicircular side. Furthermore, one lightening hole 3j is provided in the lower half of the wheel mounting flange 3b, directly below the rotation axis X. Note that the number and arrangement of the lightening holes 3j are not limited to those shown in the embodiment. This adjusts the center of gravity of the wheel pilot portion 3g, preventing uneven locations of sticking.

Also, as shown in Figure 7, a protrusion 13c can be provided on the inner diameter of the brake rotor 13, which is a brake component. In Figure 7, the brake rotor 13, which is one of the brake components, has a brake-side mounting flange 13a that joins with the wheel mounting flange 3b, and a brake rotor body 13b that fits into the wheel pilot portion 3g. A protrusion 13c is provided on the inner diameter surface of the brake rotor body 13b.

The protrusion 13c is arc-shaped in cross section and is positioned directly above the rotation axis X. Furthermore, one recess 3h provided in the wheel pilot portion 3g is positioned directly above the rotation axis X. The radius of the protrusion 13c is approximately the same as or smaller than the radius of the recess 3h. This configuration allows for alignment by engaging the protrusion 13c with the recess 3h when mating the brake rotor body 13b and the wheel pilot portion 3g.

In addition, to ensure smooth engagement with the brake rotor 13, it is preferable that the surface roughness of the protrusions 13c be Ra 6.3 or less. Furthermore, it is preferable that the flange runout between the wheel mounting flange 3b and the brake-side mounting flange 13a be 0.1 mm or less.

In this embodiment, the brake rotor 13, which is a brake component, is used as the member that engages with the wheel pilot portion 3g, but this is not limited to this. For example, a protrusion may be provided on the inner diameter surface of the wheel.

It is also possible to apply a plating coating to the outer peripheral surface of the wheel pilot portion 3g. The plating coating is applied to the outer peripheral surface of the wheel pilot portion 3g that comes into contact with the wheel or brake component. This configuration reduces the occurrence of rust between the outer peripheral surface of the wheel pilot portion 3g and the inner diameter surface of the wheel or brake component, and alleviates adhesion.

In this embodiment, the wheel bearing device 1 is configured as a wheel bearing device 1 with a third-generation structure in which the inner raceway surface 3c is formed directly on the outer periphery of the hub wheel 3, but this is not limited to this and it may also be a second-generation structure in which a pair of inner rings 4 are press-fitted and fixed to the hub wheel 3.

Furthermore, the wheel bearing device 1 in this embodiment is configured as a hub bolt type wheel bearing device 1 in which hub bolts 3e are pressed into bolt holes 3f, which are multiple insertion holes formed in the wheel mounting flange 3b, but this is not limited to this, and the wheel bearing device may be a wheel bolt type wheel bearing device in which bolts are pressed into the mounting flange on the wheel side and bolt holes are provided on the hub wheel side for screwing in the bolts.
In this case, since there is no need to arrange the hub bolts on the wheel mounting flange 3b side, the recess 3h may be arranged at any position.

Although the embodiments of the present invention have been described above, the present invention is in no way limited to these embodiments, which are merely illustrative, and it goes without saying that the present invention can be embodied in a variety of other forms without departing from the spirit of the present invention. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, as well as all modifications within the scope of the claims.

REFERENCE SIGNS LIST 1 Wheel bearing device 2 Outer ring 2a Inner side opening 2c (Inner side) outer raceway surface 2d (Outer side) outer raceway surface 3 Hub ring 3a Small diameter step portion 3c (Hub ring) inner raceway surface 3d Seal land portion 3e Hub bolt 3f Bolt hole 3g Wheel pilot portion 3h Recessed portion 3i Base end portion 3j Lightening hole 4 Inner ring 4a (Inner ring) inner raceway surface 5 Inner side ball row 6 Outer side ball row 11 Magnetic encoder 12 Sensor holder 13 Brake rotor 13a Brake side mounting flange 13b Brake rotor body 13c Protrusion

Claims (7)

an outer member having a double-row outer rolling surface formed on an inner periphery thereof;
an inner member comprising a hub ring having an integral wheel mounting flange on the outboard side and having a cylindrical small diameter stepped portion formed on its outer periphery extending in the axial direction, and at least one inner ring press-fitted into the small diameter stepped portion of the hub ring, the inner member having a double row inner raceway surface formed on its outer periphery opposite the double row outer raceway surface;
a double row of rolling elements rollably accommodated between the rolling surfaces,
the hub wheel has a wheel pilot portion that extends outboard of the wheel mounting flange and guides the inner diameter surface of the wheel, and a recess having a depth of 1 to 3 mm is formed on the outer peripheral surface of the wheel pilot portion ,
The recesses are arranged asymmetrically about the axial direction,
A lightening hole is provided in the wheel mounting flange to adjust the center of gravity of the hub wheel.
A wheel bearing device characterized in that: A wheel bearing device as recited in claim 1, wherein the wheel mounting flange is provided with an insertion hole for inserting a hub bolt, and the insertion hole and the recess are circumferentially out of phase with each other when viewed axially. 3. The wheel bearing device according to claim 1 , wherein a ratio of the total circumferential length of said recessed portion to the circumferential length of said wheel pilot is 35 to 75%. 4. The wheel bearing device according to claim 1 , wherein a radius of curvature of the raised portion between the wheel mounting flange and the wheel pilot portion is 2 mm or more and 5 mm or less. The wheel bearing device according to any one of claims 1 to 4 , wherein a chamfer is provided on an outer peripheral edge of the recess. The wheel bearing device according to any one of claims 1 to 5 , wherein a plated surface is formed on the outer peripheral surface of the wheel pilot by painting. A wheel bearing device as described in claim 1, wherein the wheel mounting flange is provided with bolt holes for threading wheel bolts.