Patent ID: 8421284

Claim:
A cooling structure for a stator of a rotating electrical machine that supplies a cooling medium to a coil end portion of the stator including a stator core and the coil end portion protruding from an end in an axial direction of the stator core, so as to cool the coil end portion, the cooling structure comprising: a cooling medium distributing member provided above a region of the coil end portion to which the cooling medium is to be supplied, the cooling medium distributing member being formed with a plurality of cooling medium discharge openings for supplying the cooling medium to the coil end portion, and a cooling medium distributing path for distributing the introduced cooling medium to the plurality of cooling medium discharge openings, wherein the cooling medium distributing path has a plurality of chambers separated by a partition wall, and an inter-chamber communication passage that is formed in the partition wall and communicates between the adjacent chambers, as the plurality of chambers, the cooling medium distributing member includes at least one cooling medium distributing chamber that divides the cooling medium distributing path by distributing the cooling medium introduced into the chamber to a plurality of the inter-chamber communication passages, and also includes a plurality of cooling medium discharge chambers having the cooling medium discharge openings formed therein, and the cooling medium distributing path is formed so as not to merge after being divided by the cooling medium distributing chamber, and regarding the plurality of inter-chamber communication passages that are formed in the partition wall surrounding the cooling medium distributing chamber and communicate with the different chambers located on a downstream side, bottom surface portions of the inter-chamber communication passages are located at the same level, and a ratio of an opening width between the different inter-chamber communication passages is set according to a ratio of a sum of opening cross-sectional areas of all of the cooling medium discharge openings which are located downstream of each of the inter-chamber communication passages.