Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
  • H02K41/02—Linear motors; Sectional motors
  • H02K41/035—DC motors; Unipolar motors
  • H02K41/0352—Unipolar motors
  • H02K41/0354—Lorentz force motors, e.g. voice coil motors
  • H02K41/0356—Lorentz force motors, e.g. voice coil motors moving along a straight path
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/12—Stationary parts of the magnetic circuit
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
  • H02K41/02—Linear motors; Sectional motors
  • H02K41/03—Synchronous motors; Motors moving step by step; Reluctance motors
  • H02K41/031—Synchronous motors; Motors moving step by step; Reluctance motors of the permanent magnet type
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
  • H04R9/02—Details
  • H04R9/025—Magnetic circuit
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R2209/00—Details of transducers of the moving-coil, moving-strip, or moving-wire type covered by H04R9/00 but not provided for in any of its subgroups
  • H04R2209/022—Aspects regarding the stray flux internal or external to the magnetic circuit, e.g. shielding, shape of magnetic circuit, flux compensation coils
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R2209/00—Details of transducers of the moving-coil, moving-strip, or moving-wire type covered by H04R9/00 but not provided for in any of its subgroups
  • H04R2209/041—Voice coil arrangements comprising more than one voice coil unit on the same bobbin
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
  • H04R9/02—Details
  • H04R9/022—Cooling arrangements

Definitions

• the present invention relates to an electrodynamic transducer magnetic motor device comprising an annular connected magnet and a tubular element supporting a coil mounted to move in translation coaxially with respect to the annular bonded magnet.
• Such a device is particularly, but not exclusively, intended to enter the composition of the electrodynamic speakers.
• Known magnetic motor devices comprise on the one hand fixed elements, an annular permanent magnet, two metal rings containing iron coaxially sandwiching the permanent magnet forming field plates, and a core also containing coaxially mounted iron.
• a coiled cylindrical support coaxially held in the air gap between the magnet and the core is a membrane connected to the wound cylindrical support.
• the cylindrical wound support is for example made of cardboard and it comprises windings son, for example copper, and the power supply of these son causes the axial movement of the wound support in the air gap and therefore the movements of the membrane. It is these movements of the membrane that then cause the vibration of the air and generate the sound.
• EP 2 1 14 086 is a magnetic motor device, without field plates, but whose permanent magnet is an annular bonded magnet, of a particular shape having a cylindrical surface and to opposite a convex surface.
• This document notably discloses a magnetic device whose bonded magnet is installed inside the wound support, the bonded magnet having an outer cylindrical surface which extends opposite the windings of wires and a convex surface which extends towards inside the magnet.
• This convex surface is such that the trace of an axial plane of the bonded magnet and the convex surface is a hemi-ellipse.
• the outer cylindrical surface has two cylindrical portions opposite to each other with respect to the median plane of the magnet.
• the field lines extend, from one part to the other inside the magnet parallel to the curvature defined by the surface of the emi-elliptical cone and in cutting substantially perpendicularly the cylindrical surface. This effectively concentrates the magnetic field to the wire windings of the wound support.
• the field lines do not close easily beyond the coiled carrier opposite the magnet.
• the document EP 2 1 14 086 discloses the implementation of a magnet connected around the wound and symmetrical support of that which is housed inside so as to close the field lines to obtain a better linearity of the magnetic field. and limit magnetic leakage.
• the implementation of an additional magnet around the wound support increases the weight and the volume of the magnetic motor device.
• the bonded magnets, plasto-magnets or elasto-magnets are low conductors of thermal energy and therefore, the thermal energy generated in the coil, where the temperature can reach 170 ° C, is very difficult to dissipate.
• a problem that arises and that aims to solve the present invention is to provide a magnetic motor device that not only allows to limit the magnetic leakage field but also the accumulation of thermal energy.
• the present invention provides an electrodynamic transducer magnetic motor device comprising, on the one hand, an annular connected magnet generating a magnetic field, and on the other hand a tubular element mounted coaxially with said annular bonded magnet, said magnet annular bond having a magnetic cylindrical surface, while said tubular element comprises a coil extending facing said magnetic cylindrical surface, said tubular element being intended to be driven axially with respect to said annular bonded magnet when said winding is supplied with electric current .
• the device further comprises a metal tubular member having a cylindrical metal surface, and said metal tubular member is mounted coaxially with said tubular member so that said cylindrical metal surface extends opposite said surface cylindrical magnetic with respect to said winding so as to close said magnetic field.
• a feature of the invention lies in the implementation of the tubular metal member opposite the annular bonded magnet relative to the wound tubular member, so as to close the magnetic field.
• the leakage field is very limited in comparison with conventional structures and the magnetic field is concentrated through the coiled tubular element.
• the thermal energy generated in the coil easily dissipates through the tubular metal member, which by nature is a good thermal conductor.
• the tubular metal member for example made of an iron alloy, makes it possible to improve the dimensional tolerances of manufacture.
• said annular bonded magnet which is obviously a solid solid, advantageously has a surface opposite to said magnetic cylindrical surface, the intersection of which with an axial plane of said annular bonded magnet is a half-ellipse.
• a hemi-ellipse is a curve defined by an ellipse cut along one of these two axes, either along its minor axis that extends between its two centers, or along its major axis that precisely intersects the two centers.
• the magnetic field lines extend, in an axial plane, a cylindrical portion located on one side of the median plane of the annular bonded magnet towards the other, through the magnet while marrying the curvature defined by the opposite hemi-elliptical surface and substantially perpendicularly cutting the cylindrical surface of the magnet. They thus pass radially through the coiled tubular element, then radially join the metal tubular member and then flex and extend therethrough in an axial direction as will be explained in more detail in the following description.
• said opposite surface has a truncation forming a truncated cylindrical surface substantially parallel to said magnetic cylindrical surface.
• said magnetic cylindrical surface of said annular bonded magnet has two cylindrical first half-surfaces, while said annular bonded magnet generates a magnetic field B, and the ratio of the first cylindrical half-surface and the straight section of the tubular member.
• metallic factor of said magnetic field B is smaller than the value of the magnetic saturation threshold of the material of said metal tubular member.
• the cross section of the tubular member corresponds to the surface of this cross section and therefore unlike the outer radius and inner radius surfaces of the tubular member.
• the required thickness of the metal tubular member is easily determined, and in particular it is avoided to a tubular organ is too bulky and heavy.
• the ratio of the first cylindrical half-surface and the cross section of the metal tubular member factor of said magnetic field B is less than 1.5 when said metal tubular member is made of iron.
• said cylindrical metal surface has two cylindrical second half-surfaces located in the axial extension of one another and also divided by a median plane of the tubular member, while said winding is divided into two windings axially spaced from each other and able to extend respectively opposite said second cylindrical half-surfaces.
• the two windings spaced axially from each other consist of a single wire, but wound in the opposite direction.
• the two windings are then respectively adjusted to the right of the two opposite parts of the annular bonded magnet, so that the two bundles of field lines passing through the two windings are oriented in the opposite directions from one another.
• the forces exerted on the coiled tubular element are double, which increases the power of the motor device.
• said annular bonded magnet is mounted within said tubular member, while said metal tubular member extends around said tubular member.
• said thermal energy generated in the windings can dissipate through the metal tubular member and radially outwardly of the motor device, when space is free around it.
• said metal tubular member is mounted inside said tubular element, while said annular bonded magnet extends around said tubular element.
• FIG. 1 is a schematic axial sectional view of a magnetic motor device according to the invention according to an alternative embodiment
• Figure 2A is a partial schematic view in axial section of detail of Figure 1;
• Figure 2B is a corresponding graph of Figure 2A showing the intensity of the local magnetic field.
• Figure 3 is a schematic view similar to Figure 2A illustrating the dimensional references.
• FIG. 1 illustrates an alternative embodiment of an electrodynamic transducer magnetic motor device 10. It comprises a receiving part 12 connected to a base 14.
• the receiving part 12 comprises a frustoconical part 16 integral with a tubular part to circular base 18.
• the frustoconical portion 16 supports a membrane 20, while the tubular portion 1 8 includes coaxially along the axis of the device Z, a tubular member 22 forming a support and secured to the membrane 20, an annular bonded magnet 24 located at the inside of the tubular element 22 and a metal tubular member 26 surrounding the tubular element 22.
• the tubular element 22 is made of cardboard, aluminum, polyimide or glass fibers or in a composite material.
• the tubular element 22 has a first cylindrical rim 28 of tubular element near the attachment to the membrane 20 and a second cylindrical rim 30 of tubular element spaced from the attachment to the membrane 20.
• it comprises a first winding 32 of a conductive wire of copper, aluminum or any other alloy of these materials, or in some cases silver, located near the first cylindrical rim 28 of tubular element and a second winding 34 of said conductive wire in the opposite direction located near the second cylindrical rim 30 of tubular element.
• the two windings 32, 34 are connected by the same conductive wire.
• the annular connected magnet 24 In the tubular part 18 and inside the tubular element 22 extends the annular connected magnet 24. It has an outer cylindrical magnetic surface 36 which extends opposite and at a distance from the tubular element 22, and the opposite, inwardly, an opposite surface 38 having, in the plane of the figure corresponding to an axial plane of the annular bonded magnet 24, a contour in the form of a half-ellipse.
• the annular bonded magnet 24 has a first median plane P M i perpendicular to the Z axis of the device.
• the annular bonded magnet 24, in its outer cylindrical magnetic surface 36, has in its upper portion, above the median plane P M i, an outer cylindrical upper half-surface 40 extending facing the first winding 32 of conducting wire and in its lower part, below the median plane P M i, a cylindrical outer half-surface 42 extending opposite the second winding 34 of conductive wire.
• annular connected magnet 24 is held in a fixed position with respect to the tubular portion 18, for example via the base 14.
• the metal tubular member 26 for example made of iron, is also held in a fixed position inside the tubular part 18 and it extends coaxially around and at a distance from the tubular element 22. It presents a second median plane P M2 coincides, in Figure 1, with the first median plane P M i of the annular bonded magnet 24. As will be explained in more detail below, the tubular element 22 is free compared to the annular bonded magnet 24 and the metal tubular member 26, and is axially movable relative thereto.
• the tubular metal member 26 has a cylindrical inner surface 45 divided into two cylindrical inner half-surfaces opposite one another with respect to the second median plane P M2 , an upper half-inner cylindrical surface 44 which extends facing the first winding 32 of conductive wire, and opposite to the second median plane P M2 a lower cylindrical inner surface 46 which extends opposite the second winding 34 of conductive wire.
• the coiled tubular element 22 is installed optimally in an annular chamber 47, or air gap, which extends between the metal bung member 26 and the annular bonded magnet 24. It is axially movable about a rest position so as to drive the diaphragm 20.
• FIG. 3 is a detailed view showing a hemisection of the annular bound magnet 24 and of the tubular metal member 26.
• the annular bonded magnet 24 has a radius R and a height H from the median plane P M i and corresponding to the height of the outer cylindrical upper half-surface 40, whereas the metallic tubular member 26 has a thickness E and an inner radius R2.
• This thickness E is determined with respect to the maximum field density before saturation of the material, and in this case iron.
• the ratio between the outer cylindrical half-surface of the annular connected magnet 24, in the air gap 47, and the cross-section of the metallic tubular member 26 along the second median plane P M 2, a factor of the magnetic field conferred by the annular bonded magnet 24, must be less than the value of the magnetic saturation threshold of the material used, for example 1, 5 for the iron.
• annular connected magnet 24 a radius R of 10 mm, a height H of 6 mm, corresponding to a total half-height of the annular bonded magnet 24, for a magnetic field of 0.4 T (Tesla) conferred by a neodymium charge of the annular bonded magnet and for the metal tubular member 26, an inner radius R2 of 1 1 mm defining an air gap 47 of 1 mm, and a thickness of the metallic tubular member 26 E of 2 mm, a field density is obtained in the tubular metal member 26 close to 1.0 T. This value is less than 1.5 T.
• FIG. 2A showing the magnetic field lines 48 which extend between the annular bonded magnet 24 and the metal tubular member 26 and to describe the advantages of the magnetic motor device according to the invention. Also in this Figure 2A partially, the tubular element 22 provided with its two windings, the first 32, and the second 34.
• the curved magnetic field lines 48 extend inside the annular connected magnet 24, in an axial section, substantially parallel to the opposite surface 38 of the magnetic cylindrical surface 36 external, to respectively open perpendicularly in the two half-surfaces 40, 42.
• These magnetic field lines 48 are here, in Figure 2A, oriented in the direction of clockwise.
• the magnetic field is oriented in the air gap 47, the upper outer half-surface 40 of the annular bonded magnet 24 towards the upper cylindrical inner half-surface 44 of the metal tubular member 26. It is then guided axially in the tubular metal member 26 towards the lower cylindrical inner half-surface 46 and traverses in the opposite direction the gap 47 to the outer cylindrical lower half-surface 42 to join the annular connected magnet 24.
• Figure 2B shows in Figure 2B in correspondence, the variations of the magnetic field in the gap 47 which is reversed in the lower part relative to the upper part, as just explained above.
• the linearity of the magnetic field that can be used in the air gap 47 is no longer linked to external elements but to the only metal tubular member 46. In this way, the sound quality of a loudspeaker produced with the magnetic motor device object of the invention is increased.
• the geometry of the metal tubular member 46 can be perfectly determined, and in particular its thickness, depending on the maximum field density of the material used, 1, 5 T in the iron.
• tubular element 22 having the two windings 32, 34 is fully adjusted in the magnetic field which allows to achieve high linearity and further improve the sound quality restored.
• the metal tubular member 26 is located around the tubular element 22, while the annular bonded magnet 24 is located inside it. In this way, and insofar as the space around the metal tubular member 26 is relatively free, the heat dissipation is great. In this way, the plastic elements used, in particular to guide the tubular element 22, are preserved from heat.
• the metal tubular member 26 and the annular bonded magnet 24 in another reverse configuration are permuted.
• the metal tubular member 26 discharges thermal energy axially.
• the opposite surface 38 of the annular connected magnet 24 has a truncation then forming a truncated cylindrical surface. 54 parallel and coaxial with the magnetic cylindrical surface 36. In this way, the annular magnet 24 is lightened.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Electromagnetism (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Reciprocating, Oscillating Or Vibrating Motors (AREA)
• Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=44209791

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Citations (4)

Family Cites Families (4)

• 2011
  • 2011-02-08 FR FR1150993A patent/FR2971385B1/fr not_active Expired - Fee Related
• 2012
  • 2012-02-07 CN CN2012800081046A patent/CN103348701A/zh active Pending
  • 2012-02-07 WO PCT/FR2012/050262 patent/WO2012107682A1/fr not_active Ceased
  • 2012-02-07 EP EP12707877.2A patent/EP2673961A1/de not_active Withdrawn
• 2014
  • 2014-03-18 US US14/217,766 patent/US20140339924A1/en not_active Abandoned
• 2016
  • 2016-12-29 US US15/394,166 patent/US20170179807A1/en not_active Abandoned

Patent Citations (4)

Non-Patent Citations (1)

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