Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1999-05-27
2001-04-17
Hannon, Thomas R. (Department: 3617)
Bearings
Rotary bearing
Antifriction bearing
C384S486000
Reexamination Certificate
active
06217225
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to wheel supporting devices for rotatably supporting wheels of passenger cars and trucks, and tapered roller bearings for supporting wheels.
A conventional wheel support device for supporting a non-driven vehicle wheel, e.g. a front wheel of a rear-wheel drive vehicle, comprises an axle (or knuckle spindle) carried by a steering knuckle, two rolling bearings mounted on the axle, and an axle hub rotatably supported by the rolling bearings and having a flange. A brake drum of a brake device and a wheel disk are mounted on the axle hub by stud bolts fixed to the flange and nuts threaded onto the stud bolts.
A back plate mounted on a flange of the steering knuckle supports a braking mechanism for applying braking force to the brake drum.
Tapered roller bearings are typically used in such wheel support devices to rotatably support the axle hub because this type of bearings are large in load capacity and high in rigidity. Tapered roller bearings are lubricated by grease sealed between the axle and the axle hub.
If grease leaks out, the tapered roller bearing may seize due to poor lubrication. If leaked grease enters the brake drum, the brake will fail, thus creating a serious safety problem. Thus, conventional wheel support devices have seal means for preventing leakage of grease, or a grease cap mounted on the outer end of the axle hub.
Such a conventional wheel support device is disclosed in Japanese utility model publication 58-85505. This device has a seal mechanism mounted between the axle and the axle hub at the inner side of a tapered roller bearing supporting the inner end of the axle hub. This needs an extra length for installation of the seal on the axle hub. This adds to the size of the entire wheel support device.
Also, since the seal mechanism uses the outer periphery of the axle as its sealing surface, it is necessary to finish the outer periphery of the axle to high accuracy. Machining of the axle is thus troublesome.
Handling of the tapered roller bearings is difficult because they are separable type roller bearings. Since a separate seal mechanism is needed besides the tapered roller bearings, assembling of the wheel support device is troublesome.
An object of this invention is to provide a wheel support device which is compact in size and easy to assemble and machine.
Another object of this invention is to provide a wheel-supporting tapered roller bearing that is easy to handle.
SUMMARY OF THE INVENTION
According to this invention, there is provided a wheel support device having an axle, a rotary member that rotates together with a wheel, roller bearings mounted on the outer surface of the axle for rotatably supporting the rotary member, the roller bearings comprising tapered roller bearings each comprising an outer ring, an inner ring, a cage mounted between the outer ring and the inner ring, tapered rollers held by the cage, and a seal means mounted between the outer and inner rings at the large-diameter end of the tapered rollers, the seal means comprising a slinger mounted to the inner ring, a metal core mounted to the outer ring, and a resilient seal fixed to the core and having sealing lips resiliently pressed against the inner surface of the slinger, the seal means holding the outer and inner rings unseparable from each other.
The rotary member may be an axle hub.
Since the tapered roller bearing has a built-in seal means, no separate seal mechanism is needed, so that the wheel supporting device can be assembled easily. Also, it is possible to reduce its size.
To reduce the manufacturing cost, the cage of the tapered roller bearing is preferably made from a synthetic resin, such as polyamide resin, because synthetic resin is easily moldable. For higher strength, the cage may be made from a polyamide resin reinforced with glass fiber.
The resilient seal of the seal means may be made up of a side lip resiliently pressed against the inner surface of the slinger, and inner and outer lips resiliently pressed against the outer periphery of the cylindrical portion of the slinger pressed onto the inner ring to effectively prevent leakage of grease and entry of muddy water. A garter spring may be put around the outer lip of the resilient seal to press the outer lip more tightly against the cylindrical portion, thereby more effectively preventing leakage of grease and entry of muddy water.
According to the second invention, there is also provided a tapered roller bearing comprising an outer ring, an inner ring, a cage mounted between the outer and inner rings, tapered rollers held by the cage, and a seal means mounted between the outer and inner rings at the large-diameter end of the tapered rollers, the seal means comprising a slinger mounted on the inner ring, a metal core mounted in the outer ring, and a resilient seal fixed to the metal core and having sealing lips resiliently pressed against the inner surface of the slinger, the outer and inner rings being held unseparable from each other by the seal means.
This tapered roller bearing is easy to handle because the inner and outer rings are unseparable.
REFERENCES:
patent: 4339374 (1982-07-01), Olschewski et al.
patent: 4799808 (1989-01-01), Otto
patent: 5553870 (1996-09-01), Czekansky et al.
Hattori Junichi
Ichikawa Hiroyuki
Shimizu Yasuhiko
Tsujimoto Takashi
Hannon Thomas R.
NTN Corporation
Wenderoth, Lind & Ponack. L.L.P.
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