Rotary expansible chamber devices – Non-metallic working member – cylinder or partition
Reexamination Certificate
2000-02-16
2001-07-24
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Non-metallic working member, cylinder or partition
C418S206900, C418S206500, C425S524000
Reexamination Certificate
active
06264449
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a plastic toothed wheel for a toothed wheel pump, the wheel body of which comprises external or internal teeth having at least one tooth cavity accessible from at least one tooth end face.
Toothed wheel pump toothed wheels of this kind are disclosed in DE GM 298 10 548.9.
The hollow tooth design of such toothed wheels, injection-molded from plastic, facilitates manufacture of teeth having uniform walls, wherein the wheel weight is considerably reduced. Prolonged lifetimes can be achieved by using special plastic materials for manufacture of the toothed wheel.
However, use of toothed wheel pumps having such toothed wheels for supplying and pressurizing engine oil in automotive vehicles leads to intolerable splashing losses when the teeth are hollow.
It is therefore the underlying purpose of the invention to further develop toothed wheels of this type in such a manner that splashing of supply media is avoided.
SUMMARY OF THE INVENTION
This object is achieved in accordance with the invention by closing the tooth cavities at the front or by filling them up with a temperature and media resistant, light-weight filling material of low specific weight.
The tooth cavities can thereby be formed with an opening penetrating completely through the teeth in the direction of the wheel axis or by shaping the teeth as basins (as viewed in longitudinal section).
In both cases, it can be advantageous to provide a lid for each front-end tooth opening e.g. via closing elements preferably formed on a covering plate which is mounted to the front end of the toothed wheel. Such covering plates can be mounted to the toothed wheel after injection-molding of the wheel body. The covering plates are preferentially disposed in the corresponding front end of the wheel body at such a depth as to end flush and coplanar with the front end of the teeth.
Such covering plates can be made from thin walled plastic or metal, in particular aluminum, and can be glued to or into the wheel body.
For toothed wheels having tooth cavities open at both tooth front ends, the covering plates to be mounted on both sides of the toothed wheel can be advantageously attached in a rigid, mutually connecting fashion using connecting elements protruding into the tooth cavities.
In a further embodiment of the invention having tooth cavities closed with covering plates mounted to one or both wheel front ends, the amount of plastic needed for producing the wheel body can be reduced and toothed wheels comprising external teeth with walls of identical geometrical shape can be effected when the wheel body comprises a hub and a toothed ring surrounding that hub at a radial distance therefrom, wherein the toothed ring and hub are connected to one another via radial bridges. The hub and toothed ring thereby define large volume cavities in the teeth which can be closed at the front end, depending on the design of the wheel body, with one or two covering plates.
Foamed plastic e.g. silicon foam can preferentially be used to fill the teeth cavities with a temperature and media resistant filling material. Either the same or different plastic materials can be used for the wheel body and the filling material. In the first case, one can use e.g. polyetheretherketone (PEEK) and in the second case polyetheretherketone (PEEK) for the wheel body and polyester (PES) for the filling material. In addition, plastic combined with ceramic powder can be used as the filling material.
Filling of the cavities with filling material can be advantageously effected directly after injection-molding the wheel body and within the injection tool (2K method).
The drawing shows embodiments of the invention.
REFERENCES:
patent: 571770 (1896-11-01), Kurz
patent: 1030083 (1912-06-01), Green
patent: 2944732 (1960-06-01), Lorenz
patent: 4086043 (1978-04-01), Howe
patent: 4717322 (1988-01-01), Masuda et al.
patent: 5244367 (1993-09-01), Aslin
patent: 5310320 (1994-05-01), Timuska
patent: 5895210 (1999-04-01), Nakaniwa et al.
patent: 687442 (1953-12-01), None
patent: 2141486 (1984-12-01), None
patent: 64-066488 (1989-03-01), None
patent: 2-102388 (1990-04-01), None
patent: 4-041984 (1992-02-01), None
Maute Alexander
Schneider Willi
Denion Thomas
Trieu Theresa
LandOfFree
Plastic toothed wheel for a toothed wheel pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Plastic toothed wheel for a toothed wheel pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plastic toothed wheel for a toothed wheel pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2508656