A bearing assembly, comprising: a retainer assembly; a bearing stationary ring; and a bearing rotary ring, the retainer assembly being disposed between the bearing stationary ring and the bearing rotary ring, a lubrication passage being provided in an end face of the bearing rotary ring; wherein the lubrication passage comprises: a first lubrication passage provided in the end face of the bearing rotary ring; wherein, the first lubrication passage extends along a circumferential direction of the bearing rotary ring; wherein the lubrication passage further comprises: a second lubrication passage provided in the end face of the bearing rotary ring; wherein, the second lubrication passage is communicated with the first lubrication passage; wherein the second lubrication passage is provided with an oil inlet and an oil outlet, the oil inlet intersects with a circumferential outer surface of the bearing rotary ring, and the oil outlet is communicated with the first lubrication passage; characterized in that the second lubrication passage is an expansion groove, and the second lubrication passage gradually expands from the oil outlet to the oil inlet. a retainer assembly; a bearing stationary ring; and a bearing rotary ring, the retainer assembly being disposed between the bearing stationary ring and the bearing rotary ring, a lubrication passage being provided in an end face of the bearing rotary ring; wherein the lubrication passage comprises: a first lubrication passage provided in the end face of the bearing rotary ring; wherein, the first lubrication passage extends along a circumferential direction of the bearing rotary ring; wherein the lubrication passage further comprises: a second lubrication passage provided in the end face of the bearing rotary ring; wherein, the second lubrication passage is communicated with the first lubrication passage; wherein the second lubrication passage is provided with an oil inlet and an oil outlet, the oil inlet intersects with a circumferential outer surface of the bearing rotary ring, and the oil outlet is communicated with the first lubrication passage; characterized in that the second lubrication passage is an expansion groove, and the second lubrication passage gradually expands from the oil outlet to the oil inlet. a first lubrication passage provided in the end face of the bearing rotary ring; wherein, the first lubrication passage extends along a circumferential direction of the bearing rotary ring; wherein the lubrication passage further comprises: a second lubrication passage provided in the end face of the bearing rotary ring; wherein, the second lubrication passage is communicated with the first lubrication passage; wherein the second lubrication passage is provided with an oil inlet and an oil outlet, the oil inlet intersects with a circumferential outer surface of the bearing rotary ring, and the oil outlet is communicated with the first lubrication passage; characterized in that the second lubrication passage is an expansion groove, and the second lubrication passage gradually expands from the oil outlet to the oil inlet. a second lubrication passage provided in the end face of the bearing rotary ring; wherein, the second lubrication passage is communicated with the first lubrication passage; wherein the second lubrication passage is provided with an oil inlet and an oil outlet, the oil inlet intersects with a circumferential outer surface of the bearing rotary ring, and the oil outlet is communicated with the first lubrication passage; characterized in that the second lubrication passage is an expansion groove, and the second lubrication passage gradually expands from the oil outlet to the oil inlet.