Liquid Cooled Rotor Assembly

• US 20090121563A1
• Filed: 12/20/2008
• Published: 05/14/2009
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Zhou, Peng, Cutler, Grant Dufresne, Kalayjian, Nicholas Robert, Augenbergs, Peteris Koch
• Granted Patent: US 7,579,725 B2
• Time in Patent Office: Days
• US Class Current: 310/54
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator

Abstract

A rotor assembly cooling system (100) and method of using same are provided. A portion of the rotor shaft (103) is hollow, the rotor shaft including an open end (107) and a closed end (105). A coolant feed tube (109) is rigidly attached to the rotor shaft (103) using one or more support members (111), thus causing the shaft and the feed tube to rotate at the same rate. Coolant is pumped through the feed tube until it exits the end of the feed tube and flows against the inside surface of the closed end of the rotor shaft causing the coolant to change direction and flow back through the coolant flow region, this region being defined as the space between the outer surface of the feed tube and the inner surface of the hollow rotor shaft.

Claims

1. A method of cooling an electric motor in an electric vehicle, said method comprising of the steps of:

rotating a rotor shaft of the electric motor at a shaft rotation rate, said rotor shaft comprised of an open end located at a first end of said rotor shaft and a closed end located at a second end of said rotor shaft;

rotating a coolant feed tube extending through said open end of said rotor shaft and positioned within a hollow portion of said rotor shaft at a tube rotation rate, wherein said tube rotation rate is equivalent to said shaft rotation rate; and

pumping a coolant through a coolant inlet located at a first end of said coolant feed tube, through said coolant feed tube, out of a coolant outlet located at a second end of said coolant feed tube, through a coolant flow region between an outer surface of said coolant feed tube and an inner surface of said hollow portion of said rotor shaft, and through said open end of said rotor shaft.

2. The method of claim 1, wherein said pumping step further comprises the steps of pumping said coolant through said coolant feed tube in a first direction and pumping said coolant through said coolant flow region in a second direction, wherein said first direction is opposite said second direction.

3. The method of claim 2, further comprising the step of redirecting said coolant from said first direction to said second direction, said redirecting step further comprising the step of pumping said coolant against an inner surface of said closed end of said rotor shaft.

4. The method of claim 1, further comprising the step of rigidly coupling said coolant feed tube to said rotor shaft.

5. The method of claim 4, wherein said step of rigidly coupling said coolant feed tube to said rotor shaft further comprises the step of rigidly coupling said coolant feed tube to said hollow portion of said rotor shaft with a plurality of support members.

6. The method of claim 4, wherein said step of rigidly coupling said coolant feed tube to said rotor shaft further comprises the step of rigidly coupling said coolant feed tube to said hollow portion of said rotor shaft with a plurality of spokes.

7. The method of claim 4, wherein said step of rigidly coupling said coolant feed tube to said rotor shaft further comprises the step of rigidly coupling said coolant feed tube to said hollow portion of said rotor shaft with a plurality of ringed members, wherein each ringed member is comprised of a first ring proximate to and attached to said outer surface of said coolant feed tube, a second ring proximate to and attached to said inner surface of said hollow portion of said rotor shaft, and a plurality of spokes rigidly coupling said first ring to said second ring.

8. The method of claim 4, wherein said step of rigidly coupling said coolant feed tube to said rotor shaft further comprises the step of rigidly coupling said coolant feed tube to said hollow portion of said rotor shaft with a plurality of ringed members, wherein an inner edge of each ringed member is proximate to and attached to said outer surface of said coolant feed tube and wherein an outer edge of each ringed member is proximate to and attached to said inner surface of said hollow portion of said rotor shaft, and wherein each ringed member is further comprised of a plurality of holes passing from a first side of said ringed member to a second side of said ringed member.

9. The method of claim 4, wherein said step of rigidly coupling said coolant feed tube to said rotor shaft further comprises the step of rigidly coupling said coolant feed tube to said hollow portion of said rotor shaft with a plurality of ringed members, wherein an inner edge of each ringed member is proximate to and attached to said outer surface of said coolant feed tube and wherein an outer edge of each ringed member is proximate to and attached to said inner surface of said hollow portion of said rotor shaft, and wherein each ringed member is further comprised of a plurality of slots passing from a first side of said ringed member to a second side of said ringed member.

10. The method of claim 4, wherein said step of rigidly coupling said coolant feed tube to said rotor shaft further comprises the step of rigidly coupling said coolant feed tube to said hollow portion of said rotor shaft with a continuous support strut helically wrapped around said coolant feed tube.