Rotary kinetic fluid motors or pumps – With lubricating – sealing – packing or bearing means having... – For shaft sealing – packing – lubricating or bearing means
Reexamination Certificate
2000-04-28
2001-08-07
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With lubricating, sealing, packing or bearing means having...
For shaft sealing, packing, lubricating or bearing means
C415S168200, C415S230000
Reexamination Certificate
active
06270312
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a cooling water pump for an internal combustion engine with a housing provided with a bearing designed to support a pump shaft and with a sealing element devised to seal the bearing against a working area containing the cooling agent as well as with a leakage chamber receiving the cooling agent that oozes through the sealing element, wherein the leakage chamber is arranged in a recess of the housing and is provided with an opening to the outside, said opening being partially closed by a locking device.
Cooling water pumps in motor vehicles are exposed to relatively critical working conditions. Long rest periods and great variations in temperature are to be overcome and maintenance-free operation over a long period of time is taken for granted. In practice it proved to be almost impossible to achieve a perfectly tight sealing of the pump, i.e., the oozing of small amounts of cooling agent must always be taken into account. It is however absolutely unwanted to let this quantity of leakage run out of the pump without further ado, since this would produce the impression of a defect.
DESCRIPTION OF THE PRIOR ART
In a previous suggestion of the applicant, a leakage chamber capable of receiving a certain quantity of cooling agent is provided in order to avoid the above-mentioned disadvantages. Little by little, the cooling agent can evaporate out of this leakage chamber without leaving any visible trace of its escape.
To produce such a leakage chamber however is intricate and makes manufacture of the cooling water pump more expensive.
EP 0 428 210 A1 discloses a cooling water pump with a leakage chamber that is designed, underneath the bearing section, as a hollow. The hollow is closed by a cap and a connecting duct is provided that connects the hollow constituting the leakage chamber with its surroundings. This solution requires that the leakage chamber itself and the connecting duct be manufactured in two separate machining operations and the closure of the hollow by the cap is intricate and prone to failure.
DE 28 46 950 C discloses a similar solution with a leakage chamber designed as a blind hole that is closed by a stopper. The stopper is equipped with an overflow in order to avoid complete flooding of the leakage chamber and to prevent the cooling agent from being pressed into the pump bearing in case of a failure. In this solution, functioning is absolutely satisfactory but production is intricate.
SUMMARY OF THE INVENTION
It is an object of the present invention to permit in the simplest possible manner provision of a leakage chamber in a cooling water pump of the type mentioned above. Particularly the housing, which is in most cases configured as a cast part, shall not become more complicated and shall be easy to manufacture.
This is achieved, according to the invention by having the opening closed by a foil, preferably by a metal foil, that is deposited on a flange facing. A particularly simple way of manufacturing the leakage chamber can thus be achieved. The foil can be an aluminum foil for example, which is commercially available in various dimensions and qualities and which can easily be given any desired shape by punching. A plastic-laminated metal foil can very easily be attached to the housing by using a hot-melt adhesive or by melting it on. A foil made only of plastic can also be used.
In a preferred embodiment, the foil is glued, soldered or welded onto a flange facing encompassing the opening. A sufficiently durable connection that copes without problems with the relatively low mechanical loads can thus be maintained.
The arrangement is very space-saving when the opening is located underneath the bearing.
It is particularly advantageous when the leakage chamber communicates via a connection channel with a space between the sealing element and the bearing.
The foil can be protected from damage by having it substantially covered by a drive gear of the cooling water pump.
The figures show a preferred embodiment of the present invention.
REFERENCES:
patent: 3981610 (1976-09-01), Ernst et al.
patent: 5660521 (1997-08-01), Serio
patent: 5785491 (1998-07-01), Ozawa et al.
patent: 5827041 (1998-10-01), Charhut
patent: 5950577 (1999-09-01), Sasaki et al.
patent: 2846950 (1980-01-01), None
patent: 428210 (1991-05-01), None
Dykema Gossett PLLC
Look Edward K.
McAleenan James M
TCG Unitech Aktiengesellschaft
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