Substrate unit, motor, and disc-driving device

The utility model provides a substrate unit, a motor, and a disc-driving device. The disc-driving device, which is used for the substrate unit, is provided with a bearing, a laminated substrate part, and a lining which takes a central axis as the center and extends from the substrate part along the axial direction. The lining is provided with a bearing maintaining part, a first projection part, and a second projection part. The interior of the bearing maintaining part maintains the cylindrical shape of the bearing. The first projection part extends to the outside of the axial direction from the bearing maintaining part. The second projection part is configured to be at a position closer to an axial lower side than the first projection part, and the lower end part of the bearing maintaining part extends to the outer side of the axial direction. The substrate part is provided with a first through hole, a peripheral part, and a thin-wall part. The first through hole is formed by an inner cylindrical side surface opposite axially to the bearing maintaining part, and passes through the substrate part along the axial direction. The peripheral part expands to the axial outer side of the first through hole. The thin-wall part is configured to be closer to the axial outer side than the peripheral part, and the axial thickness of the thin-wall part is less than the axial thickness of the peripheral part. The lining is configured to be in the first through hole. The peripheral part is configured to be between the first projection part and the second projection part.