PUMP UNIT FOR ELECTRONICALLY CONTROLLED BRAKE SYSTEM

1 . A pump unit for an electronically controlled brake system, the electronically controlled brake system comprising: the pump unit connected to first and second hydraulic circuits that connect a master cylinder assembly and a plurality of brake cylinders to each other to define closed circuits, the pump unit serving to pressurize and recirculate oil; and a motor unit to drive the pump unit,

wherein the motor unit includes a motor body having a rotating shaft, and a shaft separably coupled to the rotating shaft, and

wherein the shaft includes a first eccentric portion arranged to be eccentric in a given direction from the shaft, and a second eccentric portion spaced apart from the first eccentric portion to have a predetermined phase difference with the first eccentric portion.

2 . The pump unit according to claim 1 , wherein concentric bearings are coupled respectively to the first and second eccentric portions.

3 . The pump unit according to claim 1 , wherein the rotating shaft has a coupling recess indented in an end thereof, and the shaft has a coupling protrusion formed at an end thereof so as to be press-fitted into the coupling recess.

4 . The pump unit according to claim 2 , wherein the concentric bearings are press-fitted.

5 . The pump unit according to claim 3 , wherein the coupling recess has a polygonal cross section.

6 . The pump unit according to claim 1 , wherein the pump unit includes first to third pumps arranged on a first plane, which intersects at a right angle with the shaft at a position corresponding to the first eccentric portion, and fourth to sixth pumps arranged on a second plane, which intersects at a right angle with the shaft at a position corresponding to the second eccentric portion.

7 . The pump unit according to claim 6 , wherein three pumps of the first to sixth pumps are connected to the first hydraulic circuit, and the remaining three pumps are connected to the second hydraulic circuit.