Patent ID: 8202071

Claim:
A motor-driven scroll type compressor comprising: a motor, wherein the motor has a rotary shaft and rotates the rotary shaft; a bearing for rotatably supporting front end of the rotary shaft; a fixed scroll member; a movable scroll member driven by rear end of the rotary shaft; a housing having therein the motor, the bearing, the fixed scroll member and the movable scroll member; compression chambers defined by the movable scroll member and the fixed scroll member cooperatively, wherein the rotation of the rotary shaft makes an orbital motion of the movable scroll member around the axis of the rotary shaft and accordingly the compression chambers are moved radially and inwardly thereby to compress the refrigerant gas; a suction chamber defined by the housing, the fixed scroll member and the movable scroll member, the suction chamber communicating with the compression chambers; a discharge chamber provided in the housing; an oil separation chamber provided in the housing and separating lubricating oil from the refrigerant gas and communicating with the discharge chamber; and a back pressure chamber provided in front of the movable scroll member in the housing, and facing to the rear end of the rotary shaft, wherein the back pressure chamber communicates with the oil separation chamber, wherein the rotary shaft includes: a first opening at a position adjacent to the front end of the rotary shaft and facing an inner surface of the bearing; a second opening at a position adjacent to the rear end of the rotary shaft and communicating with the back pressure chamber; a communication passage interconnecting the first opening and the second opening, wherein the first opening, the second opening and the communication passage cooperate to form an oil supply passage; and a throttle formed by a clearance between the first opening and the inner surface of the bearing.