Pumps – Motor driven – Pump within rotary working member
Reexamination Certificate
1999-09-28
2001-04-24
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Pump within rotary working member
C417S423700, C415S055100, C416S003000
Reexamination Certificate
active
06220826
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a delivery unit for motor fuel.
In a known delivery unit of this type for pumping motor fuel from a fuel tank to an internal combustion engine of a motor vehicle (International Patent Disclosure WO 95/25885), the feed pump and the electric motor for driving it are disposed side by side in the same housing. The pump wheel or impeller, which is occupied with vanes or impeller blades on its circumference, is seated in a manner fixed against relative rotation on a shaft of the rotor or impeller; this rotor or impeller carries a rotor or armature winding resting in slots, and it revolves in a stator occupied by permanent magnet segments. The delivery of electrical current to the armature winding is made via a commutator, seated on the rotor shaft, and via two current brushes resting radially on the commutator with spring pressure.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a delivery unit for motor fuel which avoids the disadvantages of the prior art.
In keeping with these objects, one feature of present invention resides, briefly stated, in a delivery unit for motor fuel, in which a rotor and an impeller of a side channel pump are a single component, and a permanent magnet is inserted with positive engagement on a circumference of this component.
The delivery unit for motor fuel according to the invention and has the advantage that by combining the rotating parts of the delivery unit, that is, the impeller of the feed pump and the rotor of the electric motor, into a single part, a very simple and compact construction is attained that can be produced with little engineering effort. In particular, the delivery unit can be made quite flat, or in other words with an extremely slight axial dimension. The resultant increased outer diameter of the delivery unit, in conjunction with the conventional embodiment of the delivery unit, is not only not a disadvantage but in fact affords the possibility of making additional provisions to improve the efficiency of the delivery unit. By dispensing with a commutator and current brushes, brush wear is no longer a factor, so that the service life of the delivery unit is increased. If the electric motor is embodied as a direct current motor, the requisite commutation of the current is performed electronically in the stator winding.
In a preferred embodiment of the invention, the cylindrical pump chamber is defined by two radially extending, axially spaced-apart side walls and one peripheral wall that joins the two side walls together along their circular periphery. The impeller faces each of the side walls with gap spacing, and the inner surface of the stator, formed by a slotted lamination packet, forms the peripheral wall of the pump chamber. The impeller has many circumferentially spaced-apart radial impeller blades that between them define axially open blade chambers and that are joined to one another by an outer ring. The permanent magnets are secured to the outer ring and, if the delivery unit is made of plastic, are preferably produced of plastoferrites.
As an alternative to this, plastic-bonded rare-earth magnets can be employed, which are preferably embedded into the plastic matrix of the impeller.
In an advantageous embodiment of the invention, a groove-like side channel open toward the pump chamber is embodied in each side wall of the pump chamber, concentrically with the impeller axis, and having an interrupter rib that remains between the end of the side channel and the beginning of the side channel, in terms of the flow direction. The beginning of at least one side channel communicates with an intake opening, and the end of the side channel communicates with a pressure outlet, and the axis of the inflow and outflow channels are oriented either axially or preferably radially from the intake opening and to the pressure outlet. Because of the especially advantageous radial inflow and outflow of fuel into and out of the pump chamber, a substantial reduction in flow losses is attained, and the pump efficiency is thus improved. In contrast to the conventional side channel pumps, the radial inflow and outflow is possible without problems, because of the outer diameter of the delivery unit that has been increased because of the design according to the invention, since as a result there is sufficient insulation space available in the radial direction to accommodate appropriate inflow and outflow channels.
REFERENCES:
patent: 5659217 (1997-08-01), Petersen
patent: 40 20 521 A1 (1992-01-01), None
patent: WO 95/25885 (1995-09-01), None
Dobler Klaus
Huebel Michael
Freay Charles G.
Robert & Bosch GmbH
Striker Michael J.
Tyler Cheryl J.
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