Patent Application
20080196917
This application claims Priority from German Application No. DE 10 2007 007 761.2, filed on Feb. 16, 2007.
The present invention relates to a fluid supply hose for a windscreen or headlamp washer system of a vehicle according to the preamble of claim 1.
On such type windscreen or headlamp washer systems, the fluid contained in the system freezes at frost temperature even if the fluid contains additives. In order to prevent the fluid from freezing, one loose single heating wire is provided in the fluid supply hose, electric power being applied to said heating wire for heating itself and the fluid when the outside temperature falls below 5° C.
This heating wire is laid in the form of a loop over the entire length of the fluid supply hose so that the two connecting ends of the heating cable are available at one point for connecting the power source. In the cross section of the fluid supply hose, the heating wire laid in the form of a loop is provided with two strands that occupy a lot of space on the one side and increase the flow resistance on the other side so that the fluid supply hose must be designed so as to have a size appropriate to ensure perfect fluid throughflow.
An electrically heated hose for a windscreen washer system of a vehicle is known from the document EP 0 456 024 A1, a heating element formed from a coaxial cable being laid in the lumen thereof. This coaxial cable has an interior heating conductor made from copper and a conducting wire mesh disposed thereabout, also made from copper, an insulation being provided between the heating conductor and the wire mesh. At a free end of the heating element, the heating conductor and the wire mesh are electrically connected together. Even if the heating element known from the document EP 0 456 024 A1 already needs less space and causes less friction loss than other prior art heating elements, the need for space could be even further reduced.
In view thereof, it is the object of the present invention to provide a fluid supply hose of the type mentioned herein above in which the heating element is of a small and flow-enhancing design so that the cross section of the fluid supply hose may be smaller.
As a technical solution to this object, a fluid supply hose for a windscreen or headlamp washer system having the features of claim 1 is proposed. Advantageous developed implementations are recited in the dependent claims.
A fluid supply hose configured according to this technical teaching has the advantage that the main heating power is obtained at the inner current conductor as a result of the higher resistance. The result thereof is that the inner current conductor can be a relatively thin implementation, this reducing the space needed therefor. In practice, one tries to limit the diameter of the entire coaxial cable to 2 mm.
Depending on the type of vehicle, the fluid supply hose of the windscreen or headlamp washer system varies in length, this also calling for different heating power in order to keep the entire windscreen or headlamp washer system from freezing. Simultaneously, the diameter of the fluid supply hose should be the same for all the vehicle types in order to avoid unnecessary manufacturing and storage costs. In order to provide a heating element having an almost constant outer diameter and still having different heating power depending on the demand, the invention relies on the observation that the resistance must be adapted while the cross section remains unchanged. In a preferred embodiment, this is achieved in that the inner current conductor is made from a copper-nickel alloy, the nickel content varying as a function of use. In one application, the inner current conductor is made for example from a CuNi2, in another it is made from a CuNi6 and in still another application from a CuNi10 alloy.
Another advantage is that a thin heating element is easy to handle and also to mount as a result thereof.
In an advantageous developed implementation, the outer current conductor is made from a tin-plated or nickel-plated copper braid.
In still another preferred embodiment, the outer current conductor is not configured to be a mesh, but is rather wrapped about the insulator and, as a result thereof, about the inner current conductor as well. It has proved advantageous if the outer current conductor covers the insulator over 80% to 98%, preferably over 95%.
Further advantages of the fluid supply hose of the invention will become apparent in the appended drawings and in the following description of embodiments thereof. Likewise, the invention lies in each and every novel feature or combination of features mentioned above or described herein after. The embodiments discussed herein are merely exemplary in nature and are not intended to limit the scope of the invention in any manner.
In said drawings:
In the
In another embodiment that has not been illustrated herein, the resistance of the inner current conductor is greater than the resistance of the outer current conductor. As a result, the coaxial cable can be implemented to be thinner, thus occupying less space in the fluid supply hose.
The coaxial cable comprises a distal and a proximal end, a plug contact that has not been illustrated in closer detail herein being provided at the proximal end of the coaxial cable 2, both on the inner current conductor 3 and on the outer current conductor 5, to connect the coaxial cable 2 to a current source. At the distal end of the coaxial cable 2, the inner current conductor and the outer current conductor 5 are electrically connected together so as to allow for current throughflow. At this point, the distal end is provided with a protecting sheath 8 intended as an insulation to protect the current conductors 3, 5 against humidity.
It is understood that the coaxial cable 2 is laid in the entire fluid supply hose in order to protect the overall windscreen or headlamp washer system and to prevent the fluid from freezing.
In
In another embodiment, the resistance of the inner current conductor may also be greater by factor of 30 or, in still another embodiment, even greater by factor of 70 than the resistance of the outer current conductor. About this outer current conductor 15 there is wrapped an insulating sheath 16 so that the coaxial cable 12 may be surrounded by water or by a water-like solution and still function properly.
The inner current conductor 13 is formed from a copper-nickel alloy, in particular a CuNi2 alloy. CuNi2 is preferably utilized with relatively long fluid supply hoses as they are found in large cars where a relatively high heating power is needed. Through the CuNi2, a relatively high resistance can be achieved in the inner current conductor without having to increase the diameter of the coaxial cable.
In smaller cars, the entire windscreen and headlamp washer system is of a smaller design so that the fluid supply hose is also smaller. As a result, less heating power is needed. In this case, it also makes sense to reduce the heating power of the heating element and as a result thereof the resistance of the inner current conductor of the coaxial cable. Since however the fluid supply hose itself has the same size for all the models, it is also desirable to utilize a coaxial cable of the same size for all the car models. For this reason, in accordance with the invention, the alloy of the inner current conductor is changed in such a manner that the resistance is lower in this case; for smaller vehicles for example, the copper nickel alloy CuNi10 is utilized.
It is understood that other copper nickel alloys having a different nickel content, such as CuNi6, may be utilized for other types of vehicles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102007007761.2 | Feb 2007 | DE | national |
