Electrical motor having radially offset cooling stream and cooling method

• US 8,686,607 B2
• Filed: 11/24/2009
• Issued: 04/01/2014
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Flender GmbH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Memminger, Oliver, Schnbauer, Norbert, Senninger, Karl, Elender, Gunther
• Primary Examiner(s): Nguyen, Tran
• Assistant Examiner(s): GONZALEZ QUINONES, JOSE A
• Application Number:
  US13/141,484
• Publication Number:
  US 20110254391A1
• Time in Patent Office: 1,589 Days
• Field of Search: 310/51, 310/52, 310/58, 310/59, 310/60.A
• US Class Current: 310/59
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 9/18 wherein the external part of the closed circuit comprises a heat exchanger structurally associated with the machine casing

Abstract

The rotor of an electrical motor should be designed simply and able to be efficiently cooled. To this end, the invention relates to an electrical motor having a rotor that has at least one radial cooling slot (16) and axially running cooling channels. The first cooling channels (18) run having their central axis at a different radial height opposite the axis of the rotor (11) than the second cooling channels (19). A spacer (29) is arranged in the at least one radial cooling slot (16) by means of which a first cooling stream (28) can be conducted from one of the first cooling channels (18) into one of the second cooling channels (19). A second partial package (T2) in the flow direction can also be supplied with cool air in this way if it flows through the first partial package (T1) in a cool region, such as near the shaft.

Claims

1. An electrical machine, comprising:

a rotor defining a rotor axis and having a single radial cooling slot to divide the rotor in midsection, said rotor including axial cooling ducts which issue into the radial cooling slot, said cooling ducts having first, second and third cooling ducts, each defined by a central axis, wherein the central axis of the first cooling duct extends in closer proximity to the rotor axis than the central axis of the second cooling duct; and

a spacer arranged in the radial cooling slot and constructed to route a first cooling stream from the first cooling duct to the second cooling duct, said spacer including a plurality of discs,

wherein a second cooling stream is introducible into the third cooling duct and directed radially to the outside by the spacer, with the third cooling duct defined by a central axis which extends coaxially to the second cooling duct,

wherein the rotor is divided into two in its axial direction by the radial cooling slot which is formed by the spacer with the discs,

wherein the discs each have a passage opening with centers rising in a direction of a cooling stream from one of the discs to a next one of the discs in a radial direction.

2. The electrical machine of claim 1, wherein the passage openings of the discs are arranged to deflect the first cooling stream in the radial direction.

3. The electrical machine of claim 1, further comprising permanent magnets which are provided to excite the rotor and which are cooled.

4. The electrical machine of claim 1, further comprising short-circuiting bars which are received in the rotor and which are cooled.

5. The electrical machine of claim 1, wherein the rotor has a laminated core comprised of a first core element which includes the first cooling duct and a second core element which includes the second cooling duct, said first core element being arranged offset in a circumferential direction relative to the second core element.

6. A method of cooling a rotor of an electrical machine, comprising the steps of:

introducing a first cooling stream axially into the rotor in a direction of a central line which extends at a first radial level in relation to an axis of the rotor;

deflecting the first cooling stream in midsection of the rotor in a single radial cooling slot in a radial direction to flow in relation to the axis of the rotor at a second radial level which is offset relative to the first radial level, which radial slot divides the rotor into two in its axial direction and is formed by a spacer with discs having passage openings with centers rising in a direction of a cooling stream from one disc to a next disc in the radial direction;

introducing a second cooling stream axially into the rotor at the second radial level; and

routing the second cooling stream radially to the outside in midsection of the rotor.

7. The method of claim 6, further comprising cooling permanent magnets provided to excite the rotor or short-circuiting bars received in the rotor.