ELECTRIC MACHINE AND METHOD FOR COOLING AN ELECTRIC MACHINE

• US 20150280520A1
• Filed: 10/09/2013
• Published: 10/01/2015
• Est. Priority Date: 10/19/2012
• Status: Active Grant

• Current Assignee: Innomotics GmbH
• Original Assignee: Siemens AG
• Inventors: Ressel, Ekkehard, Hmer, THOMAS
• Granted Patent: US 9,680,353 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02K 5/24 specially adapted for suppression or reduction of noise or vibrations
• CPC Class Codes: H02K 9/06 with fans or impellers driven by the machine shaft
• 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

An electric machine includes an inner fan in an inner cooling circuit and an outer fan for producing an outer coolant flow that is separate from the inner cooling circuit. The inner and outer fans are connected to a common shaft of the electric machine and have opposite delivery directions along an axial direction of the electric machine. The outer fan is arranged in a fan housing which has an inlet opening for the inward flow of a coolant of the outer coolant flow, and includes an air directing device, which guides the coolant in a line section which extends in the radial direction of the electric machine from the inlet opening towards the outer fan.

Claims

1-10. -10. (canceled)

11. An electrical machine, comprising:

a shaft defining an axis;

an inner fan connected to the shaft and disposed in an inner coolant circuit, said inner fan being configured to operate in a first axial direction of conveyance;

an outer fan connected to the shaft and configured to produce an outer coolant flow which is separate from the inner coolant circuit in a second axial direction of conveyance opposite to the first axial direction of conveyance and to divert the outer coolant flow in an axial direction;

a fan housing accommodating the outer fan and having an inlet opening for inward flow of a coolant of the outer coolant flow;

a first air guidance device formed by an inner wall of the fan housing and an air guidance element to guide the coolant in a line section which extends in a direction radially to the axis from the inlet opening to the outer fan;

a second air guidance device disposed on an outer surface of the fan housing such that an axial channel is defined between the outer surface of the fan housing and an inner wall of the second air guidance device, said second air guidance device having an inlet opening configured to permit flow of coolant into the channel essentially along the axial direction, with the coolant flowing through the axial channel in a direction opposite to the second axial direction of conveyance; and

a cooler housing through which the outer coolant flow from the outer fan flows, said cooler housing having an outlet opening disposed at a distance from the inlet opening of the first air guidance device in an area of a drive side of the electrical machine, with the inlet opening of the first air guidance device disposed on a non-drive side of the electrical machine.

12. The electrical machine of claim 11, wherein the second air guidance device and the fan housing are made in one piece.

13. The electrical machine of claim 11, further comprising a sound-deadening element disposed on the inner wall of the second air guidance device and/or the inner wall of the fan housing.

14. The electrical machine of claim 11, further comprising a grating element disposed on the inlet opening of the fan housing and/or on the inlet opening of the second air guidance device.

15. A method for cooling an electrical machine having an inner fan, an outer fan, a shaft for support of the inner and outer fans, and a fan housing which houses the outer fan and includes a first air guidance device and an inlet opening for inward flow of a coolant of the outer coolant flow, with the inner and outer fans having opposing directions of conveyance along an axial direction of the electrical machine, said method comprising:

forming the first air guidance device by an inner wall of the fan housing and an air guidance element;

creating an inner coolant circuit with the inner fan;

creating an outer coolant flow separated from the inner coolant circuit with the outer fan;

guiding the coolant with the first air guidance device of the fan housing in a line section which extends in a radial direction of the electrical machine from the inlet opening to the outer fan;

arranging a second air guidance device on an outer surface of the fan housing to thereby form an axial channel between the outer surface and an inner wall of the second air guidance device;

creating an inflow of the coolant essentially along the axial direction into the channel from an inlet opening of the second air guidance device;

allowing the coolant to flow axially in a direction opposite to a direction of conveyance of the outer fan through the axial channel;

routing the outer coolant flow from the outer fan through a cooler housing by diverting the coolant from the outer fan in the axial direction, wherein an outlet opening of the cooler housing is disposed at a distance from the inlet opening of the first air guidance, wherein the outlet opening is disposed in an area of a drive side of the electrical machine and the inlet opening is disposed on a non-drive side of the electrical machine.