Hollow shaft for the drive train of a ship

(42) Date of commencement of the patent: 15. 2.1998 (45) Date of issue: 25. 9.1998 (73) Patentee:

DR. ING. GEISLINGER & CO. SCHWTNGUNGSTECWIK SOCIETY MBH

A-5300 HALLWANG, SALZBURG (AT).

(54) HOLLOW SHAFT SHAFT SHAFT (57) A shaft shaft of a marine propulsion system has a shaft tube made of load-bearing laminate, in particular fiber-reinforced epoxy resin. In order to achieve a high fire resistance in a rational manner, the shaft tube is provided with a directly applied to the laminate protective cover made of fire-resistant material and the shaft strand at least in the length of this wave tube a cooling device, preferably a Wasserberieselungsanlage assigned

CQ

AT 404 246

Π® 6878618

AT 404 246 Β

The invention relates to a hollow shaft for the shaft train of a marine propulsion system with a shaft tube made of load-bearing laminate, in particular fiber-reinforced epoxy resin.

For safety reasons, there is the requirement for passenger ships that the ship even at the outbreak of a fire in any room under their own power must reach an emergency port, which is considered fulfilled, if the drive system, in particular the shaft train of this Artriebsanlage, at least 60 minutes long Fire resistance and ensures the required torque transmission in this time. If the shaft train also leads from the engine compartment through other engine rooms, then at least the shaft sections belonging to these rooms must be fire-protected so that the requirement can be met. With the use of steel shafts, this is relatively easy, but arise when using hollow shafts made of fiber reinforced plastic as they are increasingly used for weight reasons, considerable difficulties, since these waves are made because of the required strength properties of fiber-reinforced epoxy resin or other supporting laminates, which Plastics in their unmodified chemical structure do not have sufficient fire or Have heat resistance. The plastics used so far are well flammable or develop under good heat flammable gases, so that they lose their structural strength after a short time in case of fire and do not bring the required fire resistance with it. It must therefore hitherto for an encapsulation or Tunnel guide the vulnerable shaft strand sections are taken care of, but this is expensive, space consuming and not least weight-bearing and therefore can not satisfy.

The invention is therefore an object of the invention to eliminate these deficiencies and to provide a hollow shaft of the type described, which ensures a rational way of compliance with the safety conditions for the case of fire.

The invention solves this problem in that the shaft tube has a directly applied to the laminate protective cover made of fire-resistant material and the shaft strand, at least in the length range of this shaft tube, a cooling device, preferably a water sprinkler associated. This protective cover can be applied with little extra effort in the course of wave tube production and shields the fire-endangered load-bearing laminate of the shaft tube against a fire and heat from until the proposed cooling device is activated and inherently takes over the further heat and fire protection of the hollow shaft. The protective cover therefore does not have to provide a fire resistance of at least 60 minutes, but to a certain extent serves as a bridging aid for the cooling device providing the required fire protection, which is preferably designed as a water sprinkler or other fire fighting system. Since the epoxy resin of the load-bearing laminate loses the ability to transmit torque during prolonged exposure to heat, even without flame development due to structure softening, and the protective cover does indeed lose the effect of fire, but can not stop the heat for a long time, is a corresponding cooling device necessary, but would be insufficient alone because of the existing response and activation time and therefore only in combination with the protective shell provides the necessary fire resistance. As a result, the required safety conditions can be met in a rational and low-cost manner, which provides the prerequisite for making plastic shafts with all their advantages also suitable for ship propulsion systems.

Since the protective cover has no supporting task to take, but only the aufreichenden insulating and fire-resistant properties must show different materials for the protective cover manufacturing can be used. Conveniently, however, the protective cover is made of a phenolic resin prepreg with glass fiber fabric, an epoxy resin prepreg consisting of glass or ceramic fibers impregnated with a fire-resistant modified epoxy resin, or an impregnated spacer fabric having a closed outer surface. These prepregs or spacer fabrics can be applied directly to the manufacturing process on the shaft tube, so that at the same time a good adhesion of the protective cover on the laminate of the shaft tube is ensured with simple coating of the shaft tube and the shaft can then be further processed in the usual way. Phenolic resin is a per se known non-flammable plastic of high brittleness, which is ideally suited as a fire protection cover also for hollow shafts. Epoxy resins must be modified accordingly to achieve the required fire resistance, with chemical or physical modification possible. In the chemical modification, halogens are usually incorporated into the epoxy resin or blends with other resins carried out and the physical modification results in an admixture of incombustible additives, but bring in addition to improving the fire resistance and deterioration of the mechanical properties with it. Spacer fabrics, in turn, are three-dimensional gifts or Knitted fabrics of sandwich construction and consist of two cover layers sewn with transverse threads. After curing of the impregnating resin, a light sandwich structure, the core layer of which essentially forms an air cushion, is formed

AT 404 246 B these spacer fabrics also provide good thermal insulation.

The inventive measure to provide the shaft tube of a plastic shaft with a fire-resistant protective cover and assign the endangered shaft section additionally a cooling device can be relatively simple and low effort even with the use of waves of combustible material achieve a high fire resistance, especially the use of these plastic shafts also possible in passenger shipbuilding.