Variable pitch helical cooling jacket

A method for cooling an electric motor or a portion thereof, comprising:

• providing a coolant into a helical channel of a cooling jacket via a coolant inlet;
• passing the coolant through the helical channel;
• and
• withdrawing the coolant from the helical channel via a coolant outlet,
• wherein the cooling jacket comprises a first flow-through loop, positioned proximate to and in fluid communication with the coolant inlet and a first turn of the helical channel, whereby coolant entering the helical channel via the coolant inlet may flow through the first flow-through loop before flowing into subsequent turns of the helical channel,
• wherein the cooling jacket further comprises a second flow-through loop, positioned proximate to and in fluid communication with the coolant outlet and a final turn of the helical channel, whereby coolant received from preceding turns of the helical channel may flow through the second flow-through loop before exiting the helical channel via the coolant outlet, and
• wherein a pitch of the helical channel substantially monotonically decreases along an axis of the helical channel such that the pitch is greatest at the first turn of the helical channel and smallest at the final turn of the helical channel.

An electric motor, comprising:

• a stator;
• and
• a cooling jacket extending over at least part of the stator, comprising:
• a coolant inlet;
• a coolant outlet;
• a helical channel, interconnecting and providing a coolant flow path between the coolant inlet and the coolant outlet;
• a first flow-through loop, positioned proximate to and in fluid communication with the coolant inlet and a first turn of the helical channel, whereby coolant entering the helical channel via the coolant inlet may flow through the first flow-through loop before flowing into subsequent turns of the helical channel;
• and
• a second flow-through loop, positioned proximate to and in fluid communication with the coolant outlet and a final turn of the helical channel, whereby coolant received from preceding turns of the helical channel may flow through the second flow-through loop before exiting the helical channel via the coolant outlet,
• wherein a pitch of the helical channel substantially monotonically decreases along an axis of the helical channel such that the pitch is greatest at the first turn of the helical channel and smallest at the final turn of the helical channel.