Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2000-01-10
2001-08-28
Footland, Lenard A. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S492000, C384S625000, C384S571000, C384S448000, C384S569000, C384S589000, C384S482000
Reexamination Certificate
active
06280093
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a supporting structure that supports wheels of a vehicle to be freely rotatable in relation to the vehicle body.
Wheels of an automobile are supported freely retractably in relation to the vehicle body by a supporting structure that uses bearings. A heavy vehicle such as a truck requires it to bear radial loads and moment loads in order to support the vehicle body tereof. On the other hand, in the case of an automobile designed with emphasis on the maneuverability on off-road ground or a rough road such as snow-covered road, such as four-wheel drive vehicle, for example, excessive bending moments may be exerted on the wheels as the vehicle runs over bumps or depressions, thus causing an impact load in the radial direction on the bearings. Thus such vehicles often employ tapered roller bearings that have high impact resistance, as the bearings for the wheel supporting structure. In the prior art, it has been common to use a plurality of (for example, two) tapered roller bearings, that are separate from a hub, for each wheel, the bearings being assembled on an axle while being separated from each other in the axial direction.
However, the conventional configuration requires it to assemble the two tapered roller bearings individually on an axle, separately from the hub. Also the conventional configuration includes a large number of parts and requires such operations as the adjustment of the bearing clearance for applying a preload to the bearing during assembly onto the axle. Consequently, there has been a limitation to the reduction of assembly cost and material cost of the parts. For four-wheel drive vehicles which are required to have high maneuverability on rough ground, especially those of compact sizes, there is a need for higher degree of freedom in design of the wheel-related components, in order to make the wheel-related section more compact and improve the ride comfort and suspension performance. Thus there is a demand for a wheel supporting structure capable of supporting radial loads and moment loads, that are equivalent to or greater than those borne by two tapered roller bearings installed separately, while being light in weight, small in size, low in cost and high in impact resistance. An object of the present invention is to provide a low cost wheel supporting structure that eliminates the needs for the adjustment of the bearing clearance during assembly onto the axle, thereby improving the workability of assembling the support structure, and is light in weight, small in size and high in impact resistance.
SUMMARY OF THE INVENTION
According to the present invention, in order to achieve the object described above, two tapered roller bearings are put together in a unit of a configuration described below, for the purpose of size reduction.
In a structure that supports wheels freely rotatably in relation to a vehicle body via a bearing section, the bearing section is formed from tapered roller bearings having an inner member, an outer member fitted onto the inner member from the outside thereof and double rows of tapered rollers interposed between the inner member and the outer member. The outer member has double raceway surfaces where the tapered rollers move rolling thereon. The inner member comprises a hub having a wheel mounting flange and an annular member fixed on the outer circumference of the hub, and has raceway surfaces, where the tapered rollers move rolling thereon, formed on the outer circumference of the hub and on the outer circumference of the annular member. The outer member has hardened layers on at least the raceway surface and in relieving recesses thereof.
With the configuration described above, since the hub and the bearing section are integrated in a unit, workability of assembling is improved, and the number of parts is reduced thereby making it possible to reduce the cost and weight when compared to a construction of the prior art. Preload can be adjusted independently on the unit in advance, thus making it unnecessary to adjust it after assembly on a vehicle. Further, because of the double-row bearing structure where two tapered roller bearings are disposed near to each other, size of the supporting structure, especially the dimension in the axial direction, can be reduced. Since the outer member has hardened layers on at least the raceway surface and in relieving recesses thereof, service life of the raceway surfaces can be elongated and the mechanical strength of the relieving recesses that have the smallest wall thickness is increased, thus increasing the impact resistance. This makes it possible to decrease the wall thickness of the outer member and make the component lighter in weight and smaller in size further.
Durability and impact resistance can be improved further by providing the inner member with hardened layers on at least the raceway surfaces and in the relieving recesses thereof.
The outer member, when provided with a flange, can be used as a mount onto the vehicle body.
The aforementioned bearing section may also be provided with wheel speed detecting means to be used in an antilock braking system. In this case, existing conventional components related to the wheels can be used without adding new parts or units around the wheels to accommodate the antilock braking system being employed.
In the structure that supports the wheels freely rotatably in relation to the vehicle body via a bearing section, a configuration as described below may also be employed.
That is, the bearing section comprises a tapered roller bearing having an inner member, an outer member fitted on the inner member from the outside, double rows of tapered rollers interposed between the inner member and the outer member, and a pair of seals that fully seal the bearing section on both ends thereof. The outer member has double raceway surfaces where the tapered rollers move rolling thereon. The inner member is formed from a hub having a wheel mounting flange and an annular member fixed on the outer circumference of the hub, and has raceway surfaces, where the tapered rollers move rolling thereon, formed on the outer circumference of the hub and on the outer circumference of the annular member. Of the pair of seals, the outer seal has three seal lips of which the seal lip located at the outermost position of the bearing section makes sliding contact with the end face of the hub flange. The inner seal has a seal lip that makes sliding contact with the mating annular metal body located between two annular metal bodies.
By employing the outer seal and the inner seal of the configuration described above, it is made possible to reduce the size and weight of the wheel supporting structure as a whole, maintain the sealing performance over an extended period of time and making it easier to assemble the seals.
According to the present invention, since the tapered roller bearing is used for the bearing section, resistance against impacts that are anticipated when running over rough ground is improved. Also the unit structure that incorporates the hub and the bearing section improves the workability of assembling and reduces the cost and weight of the structure through the reduction of the number of parts. Moreover, the double-row configuration where the bearing sections are installed nearer to each other makes it possible to reduce the size of the supporting structure, particularly the dimension in the axial direction, and increase the degree of freedom in the design of the wheel-related section, thus making the supporting structure that can be mounted with sufficient margin on a compact vehicle where the mounting space is severely limited.
REFERENCES:
patent: 4448461 (1984-05-01), Otto
patent: 4880281 (1989-11-01), Merkelbach
patent: 5494358 (1996-02-01), Dougherty
Norimatsu Takayuki
Ohtsuki Hisashi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Footland Lenard A.
NTN Corporation
LandOfFree
Wheel supporting structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wheel supporting structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wheel supporting structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2511665