Track-type machines, such as excavators, bulldozers, track-loaders and skid-steer loaders, are used in a variety of applications. Generally speaking, these machines have an operator station, a power source, an undercarriage and a pair of track systems laterally flanking the machine. Each track system may include a roller frame positioned along a lengthwise-extending direction of the track-type machine, a drive sprocket mounted on the roller frame and rotatably driven by the power source, and one or more idler wheels also mounted for rotation on the roller frame. An endless track that circumscribes the drive sprocket and the one or more idler wheels. The endless track is engaged by the drive sprocket so the power source can drive the endless track over the drive sprocket and the idler wheels and propel the track type-machine over a work surface. To further separate the endless track from the roller frame and cause the endless track to have a desired shape for driving the track-type machine, known track systems typically include one or more upper and/or lower track roller assemblies. These track roller assemblies are located along the lengthwise-extending axis of the roller frame between the drive sprocket and the one or more idler wheels to force the endless track along the desired path.
The track roller assemblies may include a roller shaft mounted to the roller frame or to a support member to the track roller assembly, and a track roller having a through-bore may be rotatably mounted on the roller shaft. The roller shaft may be fixed in place and the track roller may rotate about the roller shaft when the track-type machine is in motion and the endless track passes over the track roller assembly. The track-type machine may operate in adverse environments wherein the track roller assemblies may be exposed to abrasive mixtures of water, dirt, sand, rock or other materials, and even chemical elements. These contaminants may enter a space between the roller shaft and the through-bore of the track roller and lead to wear of the surfaces of the roller shaft and the through-bore. Accordingly, track roller seals may be utilized to prevent the afore-mentioned contaminants from entering the space between the roller shaft and the through-bore, and to retain lubricant within the space between the roller shaft and the through-bore to minimize friction and wear in the track roller assembly.
Track roller seals of the type generally described above are known in the art. For example, U.S. Pat. No. 6,568,684 issued to Bedford et al. on May 27, 2003, and entitled “Method of Forming a Seal Assembly Around a Shaft,” discloses a method for forming a seal assembly around a shaft. More specifically, a track roller seal utilizing two seal members engaging at a seal face limits ingress of contaminants into the track roller and mitigates leakage of lubricant from the track roller.