Patent Grant
5158030
The invention described herein may be manufactured and used by or for the Government of The United States of America for governmental purposes without the payment of any royalties thereon or therefore. (1) Field of the Invention The instant invention relates to vibrational and acoustical damping in underwater vehicles and more particularly relates to a damped flexible seal assembly for the drive shaft of a torpedo. (2) Description of the Prior Art The use of flexible materials for vibration damping purposes in watercraft has heretofore been known in the art. In this regard, the U.S. Pat. Nos. 3,139,056 to Boswell et al; 4,755,154 to Eubank; and 4,756,264 also to Eubank represent the closest prior art to the instant invention of which the applicant is aware. The Boswell patent discloses a torpedo having an acoustically isolated nose section wherein a rubber-like material is disposed between the nose section and the body of the torpedo. Similarly, the U.S. Pat. Nos. 4,756,264, and 4,755,154 to Eubank disclose noise damping systems for torpedoes wherein a layer of elastomeric material is utilized to provide acoustic attenuation between parts in a torpedo. The use of flexible materials for sealing rotating drive shafts in watercraft is also known in the art. The U.S. Pat. No. 4,732,396 to Brinham is representative of apparatus incorporating flexible sealing materials. Many state of the art watercraft, including torpedoes, are currently being designed with drive shaft assemblies which have an inner rotating drive shaft and an outer non-rotating surface. In these types of designs a primary water seal is included between the outer non-rotating surface of the drive shaft assembly and the inner mating surface of the torpedo tailcone. It has been found that this seal, while providing a watertight barrier, also provides a direct coupling path for transferring vibrational energy from the propulsion motor and/or drive shaft assembly to the tailcone, which has been shown to be an efficient acoustic radiator. Hence, it has been determined that there is a need for a seal which provides a mechanical sealing function as well as a damping function for isolating the tailcone from vibratory energy present in the drive shaft. The instant invention provides a damped flexible seal assembly for a drive shaft assembly of a torpedo. The seal assembly effectively forms a watertight seal between a stationary outside surface of the drive shaft assembly and an inside mating surface of a tailcone of the torpedo, and isolates the tailcone from vibrational energy present in the drive shaft. The flexible seal assembly includes a pair of annular outside flanges, an annular inside flange, and two annular, cast-in-place, elastomeric seals which are positioned between the outside flanges and the inside flange. The outside flanges each include an inwardly facing groove and an O-ring constrained therein for providing a watertight seal against the outer surface of the sealing tube of the drive shaft assembly. The inside flange includes an outwardly-facing groove and an O-ring constrained therein for providing a watertight seal against the inner surface of the tailcone. The elastomeric seals provide a watertight, yet flexible barrier between the flanges, while also providing a damping barrier between the outside flanges and the inside flange for damping vibrational energy present in the drive shaft assembly before it can reach the tailcone through the seal assembly. Accordingly, it is an object of the instant invention to provide a mechanical seal for the drive shaft of a torpedo. It is another object to provide a flexible seal which effectively forms a watertight seal between the outside surface of the drive shaft assembly and the inside surface of the tailcone of the torpedo. It is yet another object to provide a damped seal which isolates the tailcone from vibrational energy present in the drive shaft.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2166259 | Meyer | Jul 1939 | |
| 2977919 | Blake | Apr 1961 | |
| 3139056 | Boswell et al. | Jun 1964 | |
| 4668110 | Egeto et al. | May 1987 | |
| 4755154 | Ewbank | Jul 1988 | |
| 5040764 | DuBois | Aug 1991 |
