# US 5,349,256 A · Linear transducer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,349,256 A - Document ID: US5349256A - Status: Granted - Kind: A - Application number: 08/052,472 - Filed: 1993-04-23 - Granted: 1994-09-20 - Earliest claimed: 1993-04-23 - Inventors: Jeffrey C. Holliday - Web page: https://patentgrep.com/patent/US5349256A ## CPC - H02K 41/0352: {Unipolar motors} - F02G 1/0435: {the engine being of the free piston type} - F05C 2225/08: Thermoplastics - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F02G: HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS (steam engine plants, special vapour plants, plants operating on either hot gas or combustion-product gases together with other fluid F01K; gas-turbine plants F02C; jet-propulsion plants F02K); USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR - F05C: INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES ## Abstract A linear transducer includes a pair of electrical conductors and first and second transducer members. The electrical conductors are spaced apart along a reference axis. The first and second transducer members are positioned transversely adjacent to each other for relative axial movement. They form a magnetic path of high permeance about each of the electrical conductors. The first transducer member includes a magnetic flux source having a transversely oriented internal magnetic field vector. It extends axially between the electrical conductors to complete two variable magnetic flux circuits. One such flux circuit links each of the conductors. The second transducer member has a magnetic flux dividing separator to variably apportion magnetic flux from the flux source between the resulting magnetic flux circuits as the transducer members move axially relative to each other. ## Claims ### Claim 1 A transducer comprising: a pair of electrical conductors spaced longitudinally from each other; first and second magnetically permeable transducer members positioned transversely adjacent to each other for relative longitudinal movement, the transducer members forming two magnetic paths of high permeance, wherein each such magnetic path links a single one of the electrical conductors; the first transducer member comprising a longitudinally-extending magnetic flux source having a transversely-oriented internal magnetic field vector, the flux source being positioned to complete two variable magnetic flux circuits, one such flux circuit being completed through each of the magnetic paths; the second transducer member having a flux dividing separator of low magnetic permeability which is positioned transversely adjacent the flux source to variably apportion magnetic flux from the flux source between the two magnetic flux circuits depending on the relative longitudinal positions of the transducer members. ### Claim 2 (depends on 1) The transducer of claim 1, wherein the magnetic flux source comprises a permanent magnet. ### Claim 3 (depends on 1) The transducer of claim 1, wherein the magnetic flux source comprises an electro-magnet. ### Claim 4 (depends on 1) The transducer of claim 1, wherein the magnetic flux dividing separator has a narrow longitudinal width so that substantially all of the magnetic flux from the magnetic flux source remains in one or the other of the magnetic circuits. ### Claim 5 (depends on 1) The transducer of claim 1, wherein the magnetic flux source is a permanent magnet having a transverse width, the transducer members forming at least one low permeability circuit gap in each magnetic flux circuit, wherein each such low permeability circuit gap has a transverse width which is less than the transverse width of the permanent magnet. ### Claim 6 (depends on 1) The transducer of claim 1, wherein: the second transducer member comprises a pair of longitudinally-opposed yoke sections, each yoke section having a pair of transversley-opposed limb faces defining gaps therebetween; the magnetic flux source is positioned to move within the gaps of the yoke sections to complete the magnetic flux circuits. ### Claim 7 (depends on 6) The transducer of claim 6, wherein the magnetic flux source comprises a permanent magnet with a transverse width, the limb faces being spaced from each other by a transverse width which is complementary to the transverse width of the permanent magnet. ### Claim 8 (depends on 6) The transducer of claim 6, wherein the magnetic flux source has a length sufficient to axially span the magnetic flux dividing separator. ### Claim 9 (depends on 6) The transducer of claim 6, wherein the electrical conductors are fixed to the yoke sections. ### Claim 10 (depends on 6) The transducer of claim 6, wherein each opposed yoke section has a generally U-shaped cross-section comprising first and second yoke limbs, the limb faces being formed along said first and second yoke limbs, the electrical conductors being positioned between the yoke limbs. ### Claim 11 (depends on 6) The transducer of claim 6, wherein each opposed yoke section has a generally U-shaped cross-section comprising first and second yoke limbs, the limb faces being formed along said first and second yoke limbs, the electrical conductors being positioned between the yoke limbs, the first limbs of the opposed yoke sections being joined to one another, the flux dividing separator being formed by a low permeance region between the second limbs of the opposed yoke sections. ### Claim 12 (depends on 1) The transducer of claim 1, wherein: the first transducer member comprises a first transducer block which receives the pair of electrical conductors and which forms the two magnetic paths; and the magnetic flux source is fixed to the first transducer block. ### Claim 13 (depends on 12) The transducer of claim 12, wherein the electrical conductors are fixed within the first transducer block. ### Claim 14 (depends on 12) The transducer of claim 12, wherein the first and second transducer blocks have complementary and transversely-adjacent surfaces, the magnetic flux source comprising a permanent magnet with a transverse width, the adjacent transducer block surfaces being spaced from one another by a width which is less than the transverse width of the permanent magnet. ### Claim 15 (depends on 12) The transducer of claim 12, wherein the magnetic flux source comprises a permanent magnet. ### Claim 16 (depends on 12) The transducer of claim 12, wherein the magnetic flux source comprises an electro-magnet. ### Claim 17 A linear transducer comprising: a pair of electrical conductors separated from one another; a yoke forming two magnetic paths of high permeance, wherein each such magnetic path links one of the electrical conductors; a magnetic flux source having a transversely-oriented internal magnetic field vector, the magnetic flux source being positioned to complete two variable magnetic flux circuits, one such flux circuit being completed through each of the magnetic paths; flux dividing means for variably apportioning magnetic flux from the magnetic flux source between the two magnetic flux circuits in response to the relative positions of the magnetic flux source and the flux dividing means. ### Claim 18 (depends on 17) The transducer of claim 17, wherein the magnetic flux source comprises a permanent magnet. ### Claim 19 (depends on 17) The transducer of claim 17, wherein the magnetic flux source comprises an electro-magnet. ### Claim 20 (depends on 17) The transducer of claim 17, wherein the flux dividing means comprises a region of low magnetic permeability between the magnetic flux circuits. ### Claim 21 (depends on 17) The transducer of claim 17, wherein: the yoke comprises a pair of opposed yoke sections, each yoke section having a pair of limb faces defining gaps therebetween, each yoke section forming one of the two magnetic paths between its limb faces; and the magnetic flux source is positioned to move within the axially extending gaps of the yoke sections to complete the magnetic flux circuits. ### Claim 22 (depends on 21) The transducer of claim 21, wherein each opposed yoke section has a generally U-shaped cross-section comprising first and second yoke limbs, the limb faces being formed along said first and second yoke limbs, the electrical conductors being positioned between the yoke limbs. ### Claim 23 (depends on 21) The transducer of claim 21, wherein each opposed yoke section has a generally U-shaped cross-section comprising first and second yoke limbs, the limb faces being formed along said first and second yoke limbs, the electrical conductors being positioned between the yoke limbs, the flux dividing means comprising a region of low permeability between the first and second limbs of the opposed yoke sections. ### Claim 24 (depends on 21) The transducer of claim 21, wherein each opposed yoke section has a generally U-shaped cross-section comprising first and second yoke limbs, the limb faces being formed along said first and second yoke limbs, the electrical conductors being positioned between the yoke limbs, the first limbs of the opposed yoke sections being joined to one another, the flux dividing means comprising a region of low permeability between the second limbs of the opposed yoke sections. ### Claim 25 (depends on 21) The transducer of claim 21, wherein the flux dividing means comprises a region of low magnetic permeability transversely adjacent the magnetic flux source between the yoke sections. ### Claim 26 (depends on 17) The linear transducer of claim 17, wherein: the yoke comprises a first transducer block which receives the pair of electrical conductors to form the two magnetic paths; the transducer further comprises a second transducer block positioned transversely-adjacent the first transducer block, the first and second transducer blocks being movable relative to each other; and the flux dividing means comprises a low permeability region within the second transducer block and transversely adjacent the magnetic flux source, the low permeability region moving along with the second transducer block. ### Claim 27 (depends on 26) The transducer of claim 26, wherein the magnetic flux source is fixed to the first transducer block. ### Claim 28 (depends on 26) The transducer of claim 26, wherein the magnetic flux source comprises a permanent magnet. ### Claim 29 (depends on 26) The transducer of claim 26, wherein the magnetic flux source comprises an electro-magnet. ### Claim 30 (depends on 26) The transducer of claim 26, wherein the first and second transducer blocks have complementary and transversely-adjacent surfaces, the magnetic flux source having a transverse width and being fixed to one of the transducer blocks, the adjacent transducer block surfaces being spaced from one another by a width which is less than the transverse width of the permanent magnet. ### Claim 31 A linear transducer comprising: a pair of annular electrical conductors spaced from one another along a reference axis; a pair of axially opposed toroidal yoke sections spaced along the reference axis, each yoke section forming a magnetic path of high permeance which links one of the electrical conductors; an annular magnetic flux source coaxially centered about the reference axis, the magnetic flux source having a transversely-oriented internal magnetic field vector and being positioned to complete two variable magnetic flux circuits, one of the flux circuits being completed through each of the magnetic paths, the magnetic flux source being axially movable; and a magnetic flux dividing separator having a low permeability, the flux dividing separator being positioned to apportion the magnetic flux from the magnetic flux source between each of the magnetic circuits depending on the relative axial positions of the magnetic flux source and the flux dividing separator. ### Claim 32 (depends on 31) The linear transducer of claim 31, wherein each electrical conductor is fixed within one of the yoke sections. ### Claim 33 (depends on 31) The linear transducer of claim 31, the magnetic flux dividing separator having a narrow axial width so that substantially all of the magnetic flux from the magnetic flux source remains in one or the other of the magnetic circuits. ### Claim 34 (depends on 31) The linear transducer of claim 31, wherein the magnetic flux source is rotatable relative to the toroidal yoke sections. ### Claim 35 (depends on 31) The linear transducer of claim 31, wherein: each toroidal yoke section has a generally U-shaped cross-section comprising transversely-opposed inner and outer limbs; the opposed inner and outer limbs form axially extending gaps therebetween, one of the electrical conductors being received between the opposed limbs of each yoke section; the magnetic flux source being positioned for axial movement within the axially extending gaps. ### Claim 36 (depends on 35) The linear transducer of claim 35, the magnetic flux source comprising a permanent magnet with a transverse width, the axially extending gaps having transverse widths which are approximately complementary to the transverse width of the magnet. ### Claim 37 (depends on 35) The linear transducer of claim 35, wherein: the outer limbs of the opposed yoke sections are axially joined to one another; the inner limbs of the opposed yoke sections extend toward one another, the magnetic flux dividing separator being formed by a region of low permeability between the inner limbs of the opposed yoke sections. ### Claim 38 (depends on 35) The linear transducer of claim 35, wherein: the inner limbs of the opposed yoke sections are axially joined to one another, forming a cylindrical inner wall; and the outer limbs of the opposed yoke sections extend toward one another, the magnetic flux dividing separator being formed by a region of low permeability between the outer limbs of the opposed sections. ### Claim 39 (depends on 35) The linear transducer of claim 35, further comprising: a plurality of spokes which extend radially from the magnetic flux source through the yoke sections; the inner limbs of the opposed yoke sections being joined to one another to form a cylindrical inner wall; and the cylindrical inner wall having axially extending slots, the spokes extending through the slots. ### Claim 40 (depends on 35) The linear transducer of claim 35, further comprising: a plurality of radials which extend from the magnetic flux source through the yoke sections. ### Claim 41 (depends on 35) The linear transducer of claim 35, further comprising: a plurality of spokes which extend radially inward from the magnetic flux source; the inner limbs of the opposed yoke sections being joined to one another to form a cylindrical inner wall; the cylindrical inner wall having axially extending slots, the spokes extending through the slots; and the outer limbs of the opposed yoke sections extending toward one another, the magnetic flux dividing separator being formed by a low permeability region between the outer limbs of the opposed yoke sections. ### Claim 42 A linear transducer comprising: a pair of electrical conductors spaced from one another along a reference axis; first and second magnetically permeable transducer members positioned to form two magnetic paths of high permeance, wherein each such magnetic path links a single one of the electrical conductors, the second transducer member having an inner surface coaxially centered about the reference axis, the first transducer member having an outer surface which is sized and shaped to fit within the second transducer member inner surface for axial movement relative thereto; a magnetic flux source positioned between the second transducer member and the first transducer member, the magnetic flux source having a transversely-oriented internal magnetic field vector, the magnetic flux source being positioned to complete two variable magnetic flux circuits, one of the flux circuits being completed through each of the magnetic paths; and a magnetic flux dividing separator having a low permeability to separate the magnetic flux circuits, the magnetic flux source and the magnetic flux dividing separator being positioned for relative axial movement between one another, whereby magnetic flux from the magnetic flux source is apportioned by the magnetic flux dividing separator between the two magnetic circuits. ### Claim 43 (depends on 42) The transducer of claim 42, wherein the electrical conductors are received within the second transducer member, the magnetic flux source being fixed to the second transducer member. ### Claim 44 (depends on 42) The transducer of claim 42, wherein the electrical conductors are received around the first transducer member, the magnetic flux source being fixed to the first transducer member outer surface. ### Claim 45 (depends on 42) The transducer of claim 42, wherein the second transducer member inner surface and the first transducer member outer surface are generally cylindrical and have complementary diameters. ### Claim 46 (depends on 42) The transducer of claim 42, wherein the first transducer member is sized and shaped to slide within the second transducer member. ### Claim 47 (depends on 42) The transducer of claim 42, wherein the first transducer member is an elongated bar of magnetically permeable material, the magnetic flux dividing separator comprising a region of low permeability material which axially bisects the elongated bar. ### Claim 48 (depends on 42) The transducer of claim 42, wherein the second transducer member comprises an elongated cylinder of magnetically permeable material, the magnetic flux dividing separator comprising a region of low permeability material axially bisecting the elongated cylinder. ### Claim 49 (depends on 42) The transducer of claim 42, wherein the magnetic flux source is a permanent magnet. ### Claim 50 (depends on 42) The transducer of claim 42, wherein the magnetic flux source is an electro-magnet. ### Claim 51 (depends on 42) The transducer of claim 42, the magnetic flux dividing separator having a narrow axial width so that substantially all of the magnetic flux from the magnetic flux source remains in one or the other of the magnetic circuits. ### Claim 52 (depends on 42) The transducer of claim 42, wherein the first and second magnetically permeable transducer members are rotatable relative to each other.