Improved Oil Sealing
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rtA NEW type of oil seal, called the Unitized seal, is now being manufactured and marketed by U.S. Industries Inc. Engineering Ltd., Burtonwood, Lancs. The design which was developed by National Oil Seals of America cuts out wear on the shaft it seals and is also ideal where the user wishes to avoid the cost of producing an expensive shaft finish and where assembly may damage a conventional seal.
The seal consists of a conventional bonded synthetic-rubber oil seal with a wear ring combined as an inseparable unit ready for installation. The wear sleeve on which the sprung seal lip runs is an integral part of the assembly and it is provided with a bonded internal rubber sleeve, which is an interference fit on the shaft. This provides a leak proof joint between the wear ring and shaft and forces the wear ring to turn with the shaft. In this way, the wear ring becomes an extension of the shaft and all the wear which would normally take place on the shaft surface occurs within the seal—replacing a seal renews both the sealing element and the wear ring.
Initial shaft finish is not critical, as the wear ring is sealed to the shaft by means of the rubber sleeve and the seal can be changed simply and quickly with no difficulties in obtaining correct location. The seal portion of the assembly can be to a variety of designs according to the application and a range of standard components are currently available.