COOLING DEVICE AND SPEED CHANGE DRIVE UNIT

A cooling structure intended to cool a rotating electrical machine (ME). The cooling structure includes a solid metal body (CM) having an overall tubular form delimited radially by a first contact surface, intended to completely radially surround the electrical machine and to be in physical contact with the electrical machine, and by a second contact surface completely radially surrounding the first contact surface and intended to be in physical contact with a first power module of the set of at least one power module so as to be able to cool the electrical machine and the power module, the cooling structure comprising a set of at least one cooling channel (CR1, CR2, CR3, CR4) formed in the solid metal body (CM), at a distance from the first contact surface and from the second contact surface, wherein a coolant is intended to circulate.