Abstract: The present invention describes an imbalance compensation element featuring spring arms for fixing onto a shaft, and that grooves in which an anaerobic adhesive can distribute itself for fixing the imbalance compensation element on a motor shaft. One embodiment includes a pump with such an imbalance compensation element. In a method for balancing such electric pumps, the axial and radial oscillation accelerations as well as the oscillation angular position of a running pump are measured. In accordance with these measurements and the balance class and balance angle values ascertained therefrom, an imbalance compensation element is fixed on the shaft. Through this invention the time and cost required for balancing pumps driven by electric motors can be reduced and the acoustic emissions can be distinctly reduced when such a pump is installed on a housing.

Abstract: An improvement in an electrical air pump having a housing with a pump mechanism at one end and an electric motor at the other end. The pump mechanism has at least one lightweight pump impeller made of plastic whose hub is press-fit on a shaft of the electric motor. The hub is provided with a plurality of grooves distributed around a bore in the hub which receives the motor shaft. The grooves form spaces between an inner surface of the hub and an outer surface of the shaft and the spaces are filled with an adhesive to bond the hub to the shaft. The grooves extend longitudinally or spirally along the entire length of the hub. The grooves are relatively shallow and have a depth of approximately 0.05 mm.

Abstract: An electrical air pump adapted for being periodically turned on and off and reversed in pumping direction. The air pump includes an electric motor adapted for electronic control and an air pump section joined by a housing as a common system. The housing has a cylindrical wall defining a first chamber in which the stator system is received and a scaling cover is engaged with the housing to seal the first chamber. The air pump section includes a pump cover sealingly engaged with the housing and defining therewith a second chamber, the rotor being of bell shape and rotatably supported in the second chamber on a pin secured in the housing and in the pump cover. The rotor is disposed with slight clearance adjacent to an end wall of the housing and the rotor projects radially beyond the cylindrical wall. The rotor has a collar and a plurality of pumping blades extending radially from the collar into an annular pumping channel of the second chamber.

Abstract: A method and apparatus for periodically air-washing a charcoal canister and for testing leak-tightness of a closed fuel supply system of an internal combustion engine in which a reversible electric air pump is installed in a line connecting the fuel system and the canister to the intake manifold of the engine upstream of the choke valve. In one direction of operation of the pump, ambient air is sucked through the canister and fed to the intake manifold to wash the canister and in the other direction of operation of the pump, air is pumped from above the choke valve in the intake manifold to the fuel system to pressurize the system to check leak-tightness thereof. When the engine is turned off, the pump is shut off and the fuel supply system is connected to the canister.

Abstract: An electrically driven air pump having a housing containing a pump unit driven from a shaft of an electric motor, the pump unit including two impellers made of plastic having hubs which are press-fit on the shaft of the electric motor. A collar is also press-fit on the shaft and abutting against the hub of one impeller on a side thereof facing the electric motor, and a lock ring made of metal is press-fit on the shaft and abuts against the hub of the other impeller on a side thereof facing away from the electric motor thereby to clamp the impellers between the collar and the lock ring. The lock ring and the hub of the adjoining impeller are formed at their mutually abutting surfaces with a tooth and groove arrangement to prevent relative rotary movement therebetween. A similar tooth and groove arrangement can be provided between the abutting surfaces of the impellers and between the abutting surfaces of the collar and the adjoining impeller.

Abstract: An electrically driven air pump having a housing, a pump mechanism in the housing and an electric motor in the housing connected in driving relation to the pump mechanism. Two spaced elastic supports support the electric motor from the housing at opposite ends of the motor. An air passage in the housing provides a flow of air past the electric motor to the pump mechanism. The air passage includes a suction nozzle supported by one of the elastic supports for supplying air to an inlet collar of a pump impeller of the pump mechanism. The suction nozzle projects into the collar for supply of the air from the electric motor to the pump mechanism.

Abstract: A carburetor for an internal combustion engine has an auxiliary starting device for delivering fuel and air to the induction passage during starting and cold running. The starting device comprises a duct opening into the induction passage downstream of the throttle means receiving fuel and air, and provided with a closure valve opened until the temperature of the engine has reached a first predetermined value. The flow of fuel entering the duct is reduced upon the engine becoming self operative. A flap located in the induction passage upstream of the opening of the main fuel delivery system is biased toward opening by the air flow around it and is resiliently biased toward closure with a force which decreases as the temperature of the engine increases.