# US 12,009,723 B2 · Electric motor with water jacket and oil-cooled stator and method for operation of the electric motor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,723 B2 - Document ID: US12009723B2 - Status: Granted - Kind: B2 - Application number: 17/448,322 - Filed: 2021-09-21 - Published: 2023-03-23 - Granted: 2024-06-11 - Earliest claimed: 2021-09-21 - Assignees: Dana Automotive Systems Group, LLC - Applicants: Dana Automotive Systems Group, LLC - Inventors: Steven Vanhee; Joachim Druant; Thibault Devreese; Luke Miller - Web page: https://patentgrep.com/patent/US12009723B2 ## CPC - H02K 5/203: {specially adapted for liquids, e.g. cooling jackets} - H02K 1/20: with channels or ducts for flow of cooling medium - H02K 1/2766: {having a flux concentration effect} - H02K 9/19: for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract Systems and methods for cooling an electric motor in an electric drive unit are provided. In one example, the electric drive unit includes electric motor with a housing with a water jacket arranged therein, a stator that includes a plurality of stator laminations positioned within the housing, and an oil inlet mounted to and extending through the housing. The plurality of stator laminations includes a radial opening that is designed to receive oil from the oil inlet and direct oil to one or more oil ducts that axially extend through at least a portion of the plurality of stator laminations. ## Claims ### Claim 1 An electric drive unit, comprising: an electric motor including: a housing including a water jacket arranged therein; a stator including a plurality of stator laminations that are positioned within the housing; an oil inlet mounted to an outer wall of the housing via multiple fasteners; and a plurality of seals provided between the oil inlet and the housing; wherein the oil inlet extends radially outward from the outer wall; wherein the oil inlet extends through the outer wall, an inner wall of the housing, and the water jacket; wherein the plurality of stator laminations include a radial opening that is designed to: receive oil from the oil inlet; and direct oil to one or more oil ducts that axially extend through at least a portion of the plurality of stator laminations; wherein the inner wall is positioned radially inward from the water jacket and the outer wall is positioned radially outward from the water jacket; wherein a working fluid in the water jacket includes water and the working fluid in the oil inlet and the one or more oil ducts is oil; and wherein the water jacket is fluidly separated from the oil inlet and the one or more oil ducts. ### Claim 2 (depends on 1) The electric drive unit of claim 1, wherein: the water jacket includes one or more coolant channels with an inner periphery defined by an outer surface of the inner wall; an inner surface of the inner wall is in face sharing contact with a peripheral surface of the stator; and the one or more oil ducts have a plurality of baffles. ### Claim 3 (depends on 1) The electric drive unit of claim 1, further comprising a ring designed to receive the oil from the one or more oil ducts. ### Claim 4 (depends on 3) The electric drive unit of claim 3, wherein the ring is a spray ring that includes an opening that directs the oil to an end winding in the stator. ### Claim 5 (depends on 1) The electric drive unit of claim 1, wherein the electric motor does not include an external oil cooler. ### Claim 6 (depends on 1) The electric drive unit of claim 1, wherein the one or more oil ducts include two ducts that extend from the radial opening in opposing axial directions. ### Claim 7 (depends on 1) The electric drive unit of claim 1, further comprising a thermal interface material arranged between the plurality of stator laminations and the housing. ### Claim 8 (depends on 1) The electric drive unit of claim 1, wherein a press-fit interface is formed between the housing and the stator. ### Claim 9 (depends on 1) The electric drive unit of claim 1, wherein the electric motor is a traction motor in a vehicle. ### Claim 10 A method for an electric motor-cooling system comprising: flowing a coolant which includes water through a water jacket in a housing that is directly coupled to a stator; flowing oil through an oil inlet that extends through the water jacket and an inner wall and an outer wall of the housing; flowing the oil from the oil inlet to one or more axially extending oil ducts that traverse at least a portion of a plurality of stator laminations; and thermally conducting heat from the oil to the water jacket through the inner wall in the housing; wherein the oil inlet extends radially outward from the outer wall; wherein the oil inlet is coupled to the outer wall via multiple fasteners; wherein the inner wall is positioned radially inward from the water jacket and the outer wall is positioned radially outward from the water jacket; wherein a working fluid in the water jacket includes water and the working fluid in the oil inlet and the one or more axially extending oil ducts is oil; wherein the water jacket is fluidly separated from the oil inlet and the one or more axially extending oil ducts; wherein a plurality of seals are provided between the oil inlet and the housing; and wherein the oil inlet extends through the outer wall, the inner wall, and the water jacket. ### Claim 11 (depends on 10) The method of claim 10, further comprising: flowing the oil from the one or more axially extending oil ducts to a spray ring; and flowing the oil from the spray ring to an end winding through an opening in the spray ring. ### Claim 12 (depends on 11) The method of claim 11, further comprising: collecting the oil from the end winding in an oil sump; flowing the oil from the oil sump to an oil pump; and flowing the oil directly from the oil pump to the oil inlet without passing through a heat exchanger. ### Claim 13 (depends on 10) The method of claim 10, wherein flowing the oil from the oil inlet to the one or more axially extending oil ducts includes flowing the oil through a radial opening that extends through the housing and is positioned axially between two of the axially extending oil ducts. ### Claim 14 An electric motor, comprising: a housing including a water jacket; a stator including a plurality of stator laminations with a peripheral surface that forms an interface with the housing; an oil inlet mounted to an outer wall of the housing via multiple fasteners; wherein the oil inlet extends through the outer wall, an inner wall of the housing, and the water jacket; and a plurality of seals provided between the oil inlet and the housing; wherein the plurality of stator laminations include a radial opening designed to: receive oil from the oil inlet; and direct the oil to a plurality of oil ducts axially extending through at least a portion of the plurality of stator laminations; wherein the plurality of oil ducts have a plurality of baffles; an oil sump coupled to the housing and configured to receive the oil from the plurality of oil ducts; and an oil pump including an inlet in fluidic communication with the oil sump; wherein an oil line extends directly from an outlet of the oil pump to the oil inlet; wherein the inner wall is positioned radially inward from the water jacket and the outer wall is positioned radially outward from the water jacket; wherein a working fluid in the water jacket includes water and the working fluid in the oil inlet and the plurality of oil ducts is oil; and wherein the water jacket is fluidly separated from the oil inlet and the plurality of oil ducts. ### Claim 15 (depends on 14) The electric motor of claim 14, wherein the interface is a press-fit interface with a thermal interface material designed to reduce a thermal resistance of the interface. ### Claim 16 (depends on 14) The electric motor of claim 14, wherein the plurality of baffles extend in radial directions.