# US 5,703,418 A · DC cooled linear motor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,418 A - Document ID: US5703418A - Status: Granted - Kind: A - Application number: 08/621,811 - Filed: 1996-03-22 - Granted: 1997-12-30 - Earliest claimed: 1996-03-22 - Assignees: Northern Magnetics, Inc. - Inventors: Shlomo Assa - Web page: https://patentgrep.com/patent/US5703418A ## CPC - H02K 41/031: {of the permanent magnet type} - H02K 3/24: with channels or ducts for cooling medium between the conductors - H02K 9/00: Arrangements for cooling or ventilating (channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A DC linear motor is cooled by providing a cooling duct extending transversely through the base mounting a coil. The coil is moveable along a track which is parallel to an extended permanent magnet. The cooling air is directed transversely along the width of the base. The compressed air passes through the duct and exits ports which extend transversely relative to the duct and the track. The air is ejected into the air gap between the permanent magnet and the coil. ## Claims ### Claim 1 A DC linear motor, comprising: a primary extending in a linear direction, a current receiving coil mounted on a base for linear movement on a track extending in the linear direction, an air gap defined between the coil and the primary, a base including means for receiving a cooling fluid, and a duct for directing the cooling fluid through the base to effect cooling, the primary being a permanent magnet having two arms, and the coil extends between the arms, such that an air gap is defined between each arm and the coil, and wherein cooling is effected in each air gaps, and wherein the duct include multiple spaced ports exiting from the duct thereby to eject cooling fluid into the air gap. ### Claim 2 (depends on 1) A motor as claimed in claim 1 wherein the base defines a width, and the duct including several ports, the ports being spaced from each other and being directed to project cooling air at spaced intervals along a width of the base. ### Claim 3 (depends on 2) A motor as claimed in claim 2 wherein the ports are directed transversely relative to the duct and the track. ### Claim 4 (depends on 2) A motor as claimed in claim 2 wherein the base is formed as a molded component, and wherein the duct is molded into place in the base, and the coil is molded into the base. ### Claim 5 (depends on 2) A motor as claimed in claim 2 wherein the cooling fluid compressed air. ### Claim 6 (depends on 2) A motor as claimed in claim 2 wherein the duct forms a closed path wherein cooling fluid cycled through the path between an inlet to the duct and an outlet from the duct. ### Claim 7 (depends on 2) A motor as claimed in claim 2 wherein the cooling fluid is selectively a liquid or a gas. ### Claim 8 (depends on 2) A motor as claimed in claim 2 wherein the coil includes multi-phase winding and including means for directing a current through the coil, the base being connected with a table, and wherein the coil, base and table are moveable together along the track. ### Claim 9 (depends on 2) A motor as claimed in claim 2 wherein the duct extends transversely relative to the track, and the duct extending substantially across a width of the base such that a cooling fluid is directed substantially across the width of the coil. ### Claim 10 A DC linear motor, comprising: a primary extending in a linear direction, a current receiving coil mounted on a base for linear movement on a track extending in the linear direction, an air gap defined between the coil and the primary, a base including means for receiving a cooling fluid, and a duct for directing the cooling fluid through the base to effect cooling, the primary being a permanent magnet having two arms, and the coil extends between the arms such that an air gap is defined between each arm and the coil, and wherein cooling is effected in each air gaps, and there being several ducts in the base, the ducts being relatively spaced from each other, and the ducts being directed transversely relative to the track, the ducts having multiple spaced ports. ### Claim 11 (depends on 10) A motor as claimed in claim 10 including several ports, the ports being spaced from each other and being directed to project cooling air at spaced intervals along a width of the base. ### Claim 12 (depends on 11) A motor as claimed in claim 11 wherein the ports are directed transversely relative to the duct and the track. ### Claim 13 A DC linear brushless motor comprising: a U-shaped permanent magnet extending in a linear direction, a coil having a multi-phased current receiving windings mounted in a base for linear movement in a track extending in the linear direction, a first air gap between one arm of the U-shaped magnet and the coil, and a second air gap between the second arm of the U-shaped magnet and the coil, a duct extending across a width of a base mounting the coil, and ports directed from the duct into both of the first air gap and the second air gap, and an inlet to the duct for a cooling gas such that the gas entering the duct exits from the ports into the air gaps between the base and the magnet. ### Claim 14 (depends on 13) A motor as claimed in claim 13 wherein the duct is formed of a non-magnetic material molded into a base, the base being formed of a non-magnetic material. ### Claim 15 (depends on 13) A motor as claimed in claim 13 wherein the base defines a width, and the duct includes several ports, the ports being spaced from each other and being directed to project cooling air at spaced intervals along the width of the base. ### Claim 16 A DC linear brushless motor comprising: a U-shaped permanent magnet extending in a linear direction, multi-phased current receiving windings of a coil mounted in a base for linear movement in a track extending in the linear direction, the base defining a width, and the duct including several ports, the ports being spaced from each other and being directed to project cooling air at spaced intervals along the width of the base, a first air gap between one arm of the U-shaped magnet and the coil, and a second air gap between the second arm of the U-shaped magnet and the coil, the ducts extending across a width of a base mounting the coils, the ducts being formed of a non-magnetic material molded into the base, the base being formed of a non-magnetic material, and an inlet to the ducts for a cooling gas such that gas entering the duct and an exit for the gas from the ducts.