# US 11,306,723 B2 · Coolant pump having an optimized bearing assembly and improved heat balance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,723 B2 - Document ID: US11306723B2 - Status: Granted - Kind: B2 - Application number: 16/961,676 - Filed: 2018-11-21 - Published: 2021-03-18 - Granted: 2022-04-19 - Earliest claimed: 2018-02-22 - Assignees: Nidec Gpm GmbH - Applicants: Nidec Gpm GmbH - Inventors: Franz Pawellek - Web page: https://patentgrep.com/patent/US11306723B2 ## CPC - F04D 13/0633: {Details of the bearings} - F04D 13/0673: {the motor being of the inside-out type} - F01P 5/12: Pump-driving arrangements - F04D 13/12: Combinations of two or more pumps (combinations with priming pumps or booster pumps to counteract vapour-lock F04D9/04) - F04D 29/026: {especially adapted for liquid pumps} - F04D 29/043: Shafts - F04D 29/046: Bearings - F04D 29/0473: {for radial pumps} - F04D 29/061: {especially adapted for liquid pumps} - F04D 29/106: {especially adapted for liquid pumps} - F01P 2005/105: {Using two or more pumps} - F01P 2005/125: {Driving auxiliary pumps electrically} - F05D 2230/22: by sintering - F05D 2300/514: Porosity - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F01P: COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES (arrangements in connection with cooling of propulsion units in vehicles B60K11/00; heat-transfer, heat-exchange or heat-storage materials C09K5/00; {cooling of gas-turbine engines F02C7/12}; heat exchange in general, radiators F28) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract An electrical coolant pump, preferably for use as an additional water pump in a vehicle, is characterised in that a radial bearing of the shaft, which is arranged between the pump impeller and the rotor, is provided by means of a radial sintered sliding bearing having a defined porosity lubricated by coolant, and a shaft seal is arranged between the radial sliding bearing and the motor chamber, wherein at least one coolant flow channel with a predetermined depth is provided in the sintered sliding bearing in an axial direction extending from the end of the sintered sliding bearing on the side of the pump chamber. ## Claims ### Claim 1 An electrical coolant pump for conveying coolant in a vehicle comprising: a pump housing with a pump chamber in which a pump impeller is rotably accommodated, an inlet and an outlet which are connected to the pump chamber; a shaft which is rotably supported at a separating element between the pump chamber and a motor chamber separated from the pump chamber, and on which the pump impeller is fixed; a dry-running electric motor with a radially inner stator and a radially outer rotor which is accommodated in the motor chamber; wherein a radial bearing of the shaft, which is arranged in an axial direction between the pump impeller and the rotor, is provided by means of a radial sintered sliding bearing having a defined porosity lubricated by coolant; and a shaft seal is arranged between the radial sliding bearing and the motor chamber; wherein at least one coolant flow channel with a predetermined depth is provided in the sintered sliding bearing in an axial direction extending from the end of the sintered sliding bearing on the side of the pump chamber. ### Claim 2 (depends on 1) The electrical coolant pump according to claim 1, wherein the coolant flow channel extends in the axial direction from the end of the sintered sliding bearing on the side of the pump chamber across 90% of the component depth of the sintered sliding bearing. ### Claim 3 (depends on 1) The electrical coolant pump according to claim 1, wherein the bearing play in the sintered sliding bearing of the shaft is set to be smaller than 10 μm. ### Claim 4 (depends on 1) The electric coolant pump according to claim 1, wherein the porosity of the sintered sliding bearing is set to more than 40%. ### Claim 5 (depends on 1) The electric coolant pump according to claim 1, wherein the rotor is formed in a pot-shaped manner, the inner face thereof faces the shaft seal and is fixed on the shaft axially intersecting the same. ### Claim 6 (depends on 1) The electric coolant pump according to claim 1, wherein an axial mounting of the shaft is provided by an axial sliding bearing which is formed by a free end of the shaft and a thrust surface at the pump housing, preferably a pump cover. ### Claim 7 (depends on 1) The electric coolant pump according to claim 1, wherein the shaft seal comprises at least two sealing lips for sealing dynamically on the shaft circumference which are arranged to seal effectively towards at least one axial side. ### Claim 8 (depends on 1) The electric coolant pump according to claim 1, wherein the stator of the electric motor is arranged in an axially intersecting manner with the at least one coolant flow channel. ### Claim 9 (depends on 1) The electric coolant pump according to claim 1, further comprising a control unit which is arranged in the motor chamber in an axial direction between the separating element and the stator. ### Claim 10 (depends on 1) The electric coolant pump according to claim 1, wherein the motor chamber comprises an opening to the atmosphere which is closed by a pressure equalizing membrane impermeable to liquid and permeable to vapor. ### Claim 11 (depends on 1) A use of an electric coolant pump according to claim 1 as a supplementary water pump in a system carrying coolant in a vehicle with a combustion machine and a main water pump.