Synchronous pumps, which are used for water discharge preferably in the washing machines, must operate on possible low grid voltage and to activate with low energy consumption.

A fan bearing group of the centrifugal pump defined in the European Patent No.

0207430, makes noise, especially during the initial start up of the pump and may cause vibrations and locking of the pump.

In another prior art reference, in EP No. 287984, the connection detail of the pump fan to the motor is defined in the synchronous pumps. An O-ring, located on a mechanical and cylindrical part, which rotates around the central axis in the coupling housing a viscous liquid, is causing loss of power, due to the friction it creates. Therefore, such pumps are starting up by using high grid voltages. More energy is being consumed due to this reason and the pump may not operate in case the voltage is low.

The purpose of this invention is to develop a pump, which has a fan-bearing group that provides the start up of the operation under low voltage conditions and which provides the reduction of the power losses.

The pump realized to attain the object of this invention has been illustrated in the attached drawings, wherein:

Figure 1-is the schematic view of a pump.

Figure 2-is the side section view of a coupling.

Figure 3-is the section view of a seal that has two internal surfaces and one side surface.

The parts in these figures have been numbered as below: 1. Pump 2. Seal 3. Shaft 4. Fan 5. Coupling 6. Fan Washer 7. Fan Holder 8. Recess 9. Body 10. Protrusion 11. Extension 12. Motor 13. Pump Body 14. Fan Housing 15. Vane 16. Side Surface 17. Internal Surface

18. Groove Pumps which are preferably used in domestic appliances, in dish washing machines and in washmachines, for the purpose of discharging comprise of a motor (12), to provide the operation of the pump, a pump body (13), which covers the motor (12), a shaft (3) which transmits the drive power received from the motor (12) a fan (4), attached the motor (12), to provide desired liquids to be sucked and pumped by a shaft (3), a coupling (5) to provide the shaft (3) itself to be rotated together with the fan (4), and a fan housing (14) which covers the fan (4) and which directs the liquids to the directions of suction and discharge.

The fan (4) includes more than one vane (15), which provide the liquid to be sucked and pumped is filled in and discharged and has a recess (8) to connect the fan (4) to the shaft (3) in the center part of the vanes (15). The recess (8) has a ladder-like structure having several cylindrical steps of different diameters and having a protrusion (10) in the form of a slice of a circle in the lowest step.

The shaft (3) is being attached to a recess (8), which has a viscous liquid in itself by a coupling (5). The coupling (5) comprises a fan washer (6) having a central bore to accommodate the shaft (3) to protect the coupling (5), a seal (2) placed below the fan washer, having a central bore to accommodate the shaft (3) to prevent the escape of the viscous liquid outside the recess and vice versa, a fan holder (7) connected to the shaft (3) under the seal preferably in a tight fit fashion, with a central bore to accommodate the shaft (3) to transmit the drive from the shaft to the fan (4).

The fan holder (7) has a cylindrical body (9) to rotate it around its axis inside the recess it is born and includes an extension piece (11) having a form of a circle

slice, connected to this body (9) to complete the protrusion (10) in the form of a chord in the recess (8) so that a gap remains in between.

The extension (11) moves in the gap, without touching the protrusion (10) in order to determine the direction of rotation of the motors in the pumps during start up.

The viscous liquid inside the recess (8) prevents noise and vibration during this movement. Hence, locking are also prevented during this phase. The viscous liquid that creates non-friction movement of the fan holder (7) connected to the shaft, within the recess by providing a sliding surface between the recess (8) and fan holder (7) facilitates the movement.

The seal (2) comprises of one or more internal surfaces (17) forming the central hole to accommodate the shaft (3); one or more grooves (18) between said surfaces; one or more side surfaces (16) wider than the internal surface (s) and contacting the whole surface of the recess; one or more grooves between side surfaces (16).

As the shaft (3) starts to rotate, it tries to rotate the coupling (5) attached to it. The fan holder (7) which has no barrier that will resist this rotation except the viscous liquid in it, starts rotating before the fan washer (6) that contacts the side surfaces of the recess (8) and the seal (2) because higher friction forces than the force that drives the shaft (3) is formed on the seal (2) that contacts all surfaces of the fan washer (6), attached in a tight fit fashion and the recess (8) due to the surface they contact. Since the area of the internal surface (17), through which the shaft (3) passes is smaller than the side surface (16) a lower friction force does not prevent the rotation of the shaft (3) due to internal surface (17), is formed. This friction force on more than one internal surface (17), among which grooves (18) are present may be further lowered.

The extension (11) rests on the protrusion (10) after the first movement of the fan holder (7), which is driven by the shaft (3) and this causes the movement of the moves coupling (5), together with the fan (4) as a single piece.

In the preferred embodiment of the invention, a side surface (16) and two internal surfaces (17) having a gap there between are used. Thus, since a smaller friction area is formed by two internal surfaces (16), the shaft (3) moves easily inside them and the escape of the viscous liquid in the recess (8) is prevented. By using a side surface (16) in full contact with the recess, the friction surface is increased and movement of the seal gets more difficult.

Thanks to this invention, the friction in the first movement has been reduced and the operation of the motor (12) by consuming less energy has been provided. As less energy is sufficient, the amount of winding wire used on motor (12) is decreased and use of lower magnetic value magnets can be used. Thus, the present pump (1) provides optimum and economic usage.