GB2279708A - Bearing with ceramic dust shields - Google Patents

Abstract

The bearing has inner 14 and outer races 16 with anti friction means 18 therebetween and a seal for retaining lubricant and preventing ingress of contaminants. The bearing is provided with a dust shield comprising a pair of ceramic members, 60, 66, one having a bull nose portion, 62, and one having a cooperating concave portion, 68, that receives the bull nose portion, that extend between the inner and outer races. The shield members permit rotation of the bearing, and their shape allows the bearing to accommodate misalignment of the shaft with respect to the housing. <IMAGE>

Description

This invention relates to bearing assemblies and more particularly to bearing assemblies constructed to prevent or materially reduce the entry of dust, dirt and other debris into the interior thereof. Such bearing assemblies find particular use in asphalt road pavers where they support the screw of the screw conveyor which distributes asphalt to the ground and wherein asphalt flows axially against and past the bearing.

Patent No.2,530,052, issued November 14, 1950, teaches a bearing including rubber rings connected to the outer race with a portion wiping the surface of the inner race.

Patent No.2,881,224, issued November 5, 1957, teaches seal means 32 bridging races 18 and 19, to prevent the entrance of foreign material into the interior of the seal 32.

Patent No.2,913,289, issued November 17, 1959, teaches a seal comprising carbon members 32 loose on shaft portion 15, magnet 38 press-fit on sleeve 32 and opposite a member 25 attached thereto, part 27 press-fit into outer race (Figs. 1 and 2) and sealed by an 0-ring to another part of the structure or sealed thereto by an 0-ring (Fig. 3), the member 27 extending radially downwardly over member 38.

Patent No.4,392,695, issued July 12, 1983, shows seals 38 and 40 to prevent dust from entering the bearing. The seals are positioned at opposite ends of the bearing and comprise sealant material 46 with felt pads 52 embedded in the sealant material 46 and held in place by washers 54.

A bearing assembly comprising: a bearing housing; a bearing shaft; an inner race connected to said bearing shaft; an outer race spaced radially from said inner race; anti-friction means between said inner and outer races; said races being receivable in said housing and being adaptabie to rotate relative to one another; said bearing being so constructed and arranged to accommodate misalignment of said shaft and said housing; seal means between said inner and outer races for retaining lubricant therebetween and substantially preventing the ingress of dirt and other foreign matter thereinto; a shield means comprising a pair of ceramic members, one member having a bull-nose portion and the other member having a concave cavity receiving said bull-nose portion, one member being connected to said inner race and another member extending radially outwardly therefrom to a location opposite said outer race and in close proximately thereto.

Figure 1 is a partial sectional view illustrating the type of bearing assembly with which the invention is concerned.

Figure 2 is an enlarged partial view of the bearing assembly of Figure 1 showing details of the shield means and its relationship to the bearing races, and Figure 3 is a sectional view of an embodiment of the invention.

In the accompanying drawings, like reference characters are used to refer to like parts.

Figure 1 illustrates a bearing assembly comprising a housing 12, an inner race 14 and an outer race 16, the races being spaced from each other and receiving a plurality of anti-friction means, such as balls 18 therebetween. The balls 18 are spaced apart by means of a ball spacer 20 of conventional construction. The inner race is adapted to encircle and be connected to a rotatable shaft 22 (shown in broken lines) by means of one or more set screws 24 receivable in threaded openings 26.

A grease fitting 28 (shown schematically) is provided whereby lubricating grease can be introduced into the bearing. To retain the grease in the assembly, one or more grease seals 30 are used. The grease seals 30 each comprise a flinger.32 press-fit into the outer race and a flinger 34 extending from the flinger 32 toward the inner race with wipers 36 therebetween. The wipers can be of an elastomer and the like, having some flexfbility to remain in contact with the inner race. At times, the wipers are made of felt, especially when the environment in which the bearing is to be used contains fluid which would adversely affect and damage elastomers.

To prevent the entrance of dirt, dust and other undesirable foreign materials into the bearing, especially when used in a dirty and dustry environment, as of farm equipment and the like, a shield means 38 is used. The shield means 38 is an annular member connected to the inner races by means of one or more set screws 40. The shield means 38 is sealed to the inner race by means of an 0-ring 42 which encircles the shaft and to the outer race by a seal ring 44. The seal ring 44 is constructed of an anti-friction material, such as TEFLON and the like. The seal ring 44, because of the material from which it is made, permits the shield means to rotate with the shaft and relative to the outer race, yet insures the continued function of the shield means to protect the bearing seals from the environment and also from being damaged by foreign objects hitting the assembly.

The protective shield means is of simple construction, uses a minimum of parts, yet is effective for the purposes of protecting the bearing assembly from damage due to foreign objects, dirt and dust.

Figure 3 illustrates an embodiment of the invention. In this embodiment, an assembly of two ceramic parts together. with a pair of elastomer members is used. A first ceramic member 60 with a projecting bull-nose portion 62 is connected by an elastomer member 64 to the shield while a second ceramic member 66 with a complementary concave portion 68 to receive the bull-nose portion 62 is connected to the bearing outer race 16.. During assembly, the assembly of ceramic parts is preloaded, thus insuring the seal of the bearing from dirt and other foreign material while permitting the relatively rotation between the shield and the outer race.

It will be appreciated that it is not intended to limit the invention to the above example only many variations being possible without departing from the scope thereof as defined by the appended claims.

Claims (2)

1. A bearing assembly comprising: a bearing housing; a bearing shaft; an inner race connected to said bearing shaft; an outer race spaced radially from said inner race; anti-friction means between said inner and outer races; said races being receivable in said housing and being adaptable to rotate relative to one another; said bearing being so constructed and arranged to accommodate misalignment of said shaft and said housing; seal means between said inner and outer races for retaining lubricant therebetween and substantially preventing the ingress of dirt and other foreign matter thereinto; - shield means comprising a pair of ceramic members, one member having a bull-nose portion and the other member having a concave cavity receiving said bull-nose portion, one member being connected to said inner race and another member extending radially outwardly therefrom to a location opposite said outer race and in close proximity thereto.

2. bearing assembly as recited in claim 1 wherein said ceramic members are resiliently connected, respectively, to said inner race and to said outer race, said ceramic membrs and said resilient connection permitting misalignment of said bearing relative to said housing and relative rotation between said races.