Coupling structure

1. A coupling structure for connecting an impeller to a motor shaft of a liquid pump, comprising:

a carrier rod sleeved on the shaft,

a middle member fixed on the carrier rod, and

a rotating seal sleeved on the carrier rod and fixed to the middle member via an interlocking structure, the middle member being separately formed with the rotating seal and the carrier rod, the rotating seal being circumferentially interlocked with the carrier rod via the interlocking structure;

wherein the middle member is a macerator fixed to the carrier rod, disposed between the impeller and the rotating seal, and arranged to limit axial movement of the rotating seal along the carrier rod;

wherein the macerator is directly keyed to the carrier rod for rotation there with;

wherein the interlocking structure includes notches formed on one of the rotating seal and the macerator and corresponding ribs formed on the other one of the rotating seal and the macerator;

wherein the interlocking structure includes fingers formed on one of the rotating seal and the macerator and disposed within corresponding recesses formed on the other one of the rotating seal and the macerator;

wherein the macerator comprises an inner tube and an outer tube, each rib is directly connected between the inner tube and the outer tube, each recess is formed by the inner tube, the two adjacent ribs and the outer tube.

2. The coupling structure of claim 1 , wherein the carrier rod is fixed on the shaft via a screw thread structure and the arrangement of the screw thread structure and the running direction of the pump are such that operating the pump tends to reinforce the connection between the carrier rod and the shaft.

3. The coupling structure of claim 1 , wherein the coupling structure further comprises a stationary seal, a rotating ring and a stationary ring, wherein the rotating seal is sealingly fixed on an outer surface of the carrier rod, the rotating ring is sealingly fixed to the rotating seal, the stationary seal is sealingly fixed to a bracket forming a part of a housing of the pump, the stationary ring is sealingly fixed to the stationary seal, and a spring urging the rotating ring into contact with the stationary ring whereby the rotating ring forms a rotatable water proof seal with the stationary ring.

4. The coupling structure of claim 3 , wherein the rotating ring is made of graphite and the stationary ring is made of ceramic.

5. The coupling structure of claim 1 , wherein the ribs are connected by the outer tube.

6. The coupling structure of claim 1 , wherein the notches are formed between adjacent fingers and the recesses are formed between adjacent ribs.

7. The coupling structure of claim 1 , wherein a lower surface of each finger is parallel to a top surface of the rotating seal.

8. The coupling structure of claim 1 , wherein the recess is an annular segment, the finger is an annular segment, there is no space formed between the recess and the space after the finger is disposed within the corresponding recess.

9. A coupling structure for connecting an impeller to a motor shaft of a liquid pump, comprising:

a carrier rod sleeved on the shaft,

a middle member fixed on the carrier rod, and

a rotating seal sleeved on the carrier rod and fixed to the middle member via an interlocking structure, the middle member being separately formed with the rotating seal and the carrier rod, the rotating seal being circumferentially interlocked with the carrier rod via the interlocking structure;

wherein the middle member is a macerator fixed to the carrier rod, disposed between the impeller and the rotating seal, and arranged to limit axial movement of the rotating seal along the carrier rod;

wherein the macerator is keyed to the carrier rod for rotation there with;

wherein the interlocking structure includes notches formed on one of the rotating seal and the macerator and corresponding ribs formed on the other one of the rotating seal and the macerator;

wherein the interlocking structure includes fingers formed on one of the rotating seal and the macerator and disposed within corresponding recesses formed on the other one of the rotating seal and the macerator;

wherein the macerator comprises an inner tube and an outer tube, each rib is directly connected between the inner tube and the outer tube, each recess is formed by the inner tube, the two adjacent ribs and the outer tube.

10. The coupling structure of claim 9 , wherein the recess is an annular segment, the finger is an annular segment, there is no space formed between the recess and the space after the finger is disposed within the corresponding recess.