US Patent 7775720 Bearing device

A bearing assembly comprises a bearing (200) having a central hole (250) and a shaft (280) received in the central hole. The bearing has at least one sloping inner surface (2522) facing to the shaft and around the central hole. A gap is formed between the sloping inner surface and shaft. A width of the gap is gradually reduced along an axial direction of the central hole. The central hole has two side holes (254, 255) each of which has a diameter smaller than that of a middle hole (252) of the central hole (250), wherein the sloping inner surface is located corresponding to the middle hole.