The invention discloses a motor and speed
reducer integrated case and a
casting and
welding method thereof. The case comprises an outer case body and an inner case body, wherein the outer case body comprises a motor case body and a speed
reducer case body which are integrally formed through high-
pressure casting; the inner case body is nested in the motor case body, a spiral
water channel rib is arranged on the outer surface of the inner case body, and spaces of the spiral
water channel rib form a spiral
water channel by being matched with an outer wall of the inner case body and the inner wall of the motor case body. According to the motor and speed
reducer integrated case, the integration degree is increased, end covers are reduced, the cost is reduced, the axial space is compressed, andthe NVH characteristic of a
system is improved. According to the
casting and
welding method, the complexity of a manufacturing process is reduced through high-
pressure casting, the batch efficiency is high, the wall thickness of the case is reduced, structures of process holes are omitted, and the radial space is compressed.