# US 2018/0323682 A1 · Vehicle propulsion system and electric motor for a vehicle propulsion system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0323682 A1 - Document ID: US20180323682A1 - Status: Published application - Kind: A1 - Application number: 15/588,794 - Filed: 2017-05-08 - Published: 2018-11-08 - Earliest claimed: 2017-05-08 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Karl A. Sime - Web page: https://patentgrep.com/patent/US20180323682A1 ## CPC - B60K 1/00: Arrangement or mounting of electrical propulsion units (B60K7/00 takes precedence; arrangement or mounting of plural diverse prime-movers for mutual or common propulsion B60K6/00) - B60K 11/02: with liquid cooling - H02K 7/006: {Structural association of a motor or generator with the drive train of a motor vehicle} - H02K 9/19: for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil - B60K 2001/006: {the electric motors} - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A vehicle propulsion system includes a rotor shaft defining a cavity within the rotor shaft and a radial hole extending from the cavity to an external surface of the rotor shaft, and a restrictor that reduces a flow of liquid through the radial hole in response to a rotational speed of the hollow rotor shaft exceeding a predetermined threshold rotational speed. ## Claims ### Claim 1 A vehicle propulsion system, the system comprising: a drive member; a transmission coupled to the drive member; a prime mover coupled to the transmission, wherein the prime mover includes a rotor shaft defining a cavity within the rotor shaft and a radial hole extending from the cavity to an external surface of the rotor shaft; and a restrictor that reduces a flow of liquid through the radial hole in response to a rotational speed of the hollow rotor shaft exceeding a predetermined threshold rotational speed. ### Claim 2 (depends on 1) The system of claim 1, wherein the restrictor reduces the flow in response to a centrifugal force exceeding a predetermined threshold. ### Claim 3 (depends on 1) The system of claim 1, wherein the restrictor comprises a cylindrical portion configured to position the restrictor within the cavity. ### Claim 4 (depends on 1) The system of claim 1, wherein the restrictor comprises a restrictor arm axially extending within the rotor shaft cavity. ### Claim 5 (depends on 4) The system of claim 4, wherein the restrictor arm defines a restrictor hole that is smaller in cross-section than the radial hole in the rotor shaft. ### Claim 6 (depends on 4) The system of claim 4, wherein a width of the restrictor arm adjacent to the radial hole is less than a distance across the radial hole in a direction aligned with the width of the restrictor arm. ### Claim 7 (depends on 4) The system of claim 4, wherein the restrictor arm comprises a spring steel arm with an extent that is biased radially inward away from the radial hole. ### Claim 8 (depends on 1) The system of claim 1, wherein the restrictor reduces the flow of liquid when the rotor shaft speed exceeds the threshold rotational speed by covering at least a portion of the cross-section of the radial hole in the rotor shaft. ### Claim 9 (depends on 1) The system of claim 1, wherein the restrictor reduces the flow of liquid in stages by reducing a flow of coolant through the radial hole to a first level at a first predetermined threshold rotational speed and to a second level at a second predetermined threshold rotational speed, wherein the first level of coolant flow is greater than the second level of coolant flow and the first predetermined threshold rotational speed is less than the second predetermined threshold rotational speed. ### Claim 10 (depends on 9) The system of claim 9, wherein the restrictor comprises: a first restrictor arm axially extending within the rotor shaft and having a first level of radially inward bias; and a second restrictor arm axially extending within the rotor shaft and having a second level of radially inward bias that is greater than the first level of radially inward bias. ### Claim 11 A vehicle propulsion system, the system comprising: a rotor shaft defining a cavity within the rotor shaft and a radial hole extending from the cavity to an external surface of the rotor shaft; and a restrictor that reduces a flow of liquid through the radial hole in response to a rotational speed of the hollow rotor shaft exceeding a predetermined threshold rotational speed. ### Claim 12 (depends on 11) The vehicle propulsion system of claim 11, wherein the restrictor reduces the flow in response to a centrifugal force exceeding a predetermined threshold. ### Claim 13 (depends on 11) The vehicle propulsion system of claim 11, wherein the restrictor comprises a cylindrical portion configured to position the restrictor within the cavity. ### Claim 14 (depends on 11) The vehicle propulsion system of claim 11, wherein the restrictor comprises a restrictor arm axially extending within the rotor shaft cavity. ### Claim 15 (depends on 14) The vehicle propulsion system of claim 14, wherein the restrictor arm defines a restrictor hole that is smaller in cross-section than the radial hole in the rotor shaft. ### Claim 16 (depends on 14) The vehicle propulsion system of claim 14, wherein a width of the restrictor arm adjacent to the radial hole is less than a distance across the radial hole in a direction aligned with the width of the restrictor arm. ### Claim 17 (depends on 14) The vehicle propulsion system of claim 14, wherein the restrictor arm comprises a spring steel arm with an extent that is biased radially inward away from the radial hole. ### Claim 18 (depends on 11) The vehicle propulsion system of claim 11, wherein the restrictor reduces the flow of liquid when the rotor shaft speed exceeds the threshold rotational speed by covering at least a portion of the cross-section of the radial hole in the rotor shaft. ### Claim 19 (depends on 11) The vehicle propulsion system of claim 11, wherein the restrictor reduces the flow of liquid in stages by reducing a flow of coolant through the radial hole to a first level at a first predetermined threshold rotational speed and to a second level at a second predetermined threshold rotational speed, wherein the first level of coolant flow is greater than the second level of coolant flow and the first predetermined threshold rotational speed is less than the second predetermined threshold rotational speed. ### Claim 20 (depends on 19) The vehicle propulsion system of claim 19, wherein the restrictor comprises: a first restrictor arm axially extending within the rotor shaft and having a first level of radially inward bias; and a second restrictor arm axially extending within the rotor shaft and having a second level of radially inward bias that is greater than the first level of radially inward bias.