Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H36/00—Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding
  • H01H36/0006—Permanent magnet actuating reed switches
  • H01H36/0013—Permanent magnet actuating reed switches characterised by the co-operation between reed switch and permanent magnet; Magnetic circuits
  • H01H36/002—Actuation by moving ferromagnetic material, switch and magnet being fixed
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H36/00—Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding
  • H01H2036/0093—Micromechanical switches actuated by a change of the magnetic field

Definitions

• the present invention relates to an electrical switching device comprising a magnetic microswitch with a movable element capable of aligning along the field lines of a magnetic field.
• the switching device according to the invention may in particular be used in a push button, a sliding button or a rotary knob, in a position switch, a shock or acceleration sensor.
• a position sensor comprising a magnetic microswitch with a movable element controlled by a magnetic effect by a movable permanent magnet.
• the permanent magnet can take at least two positions to subject the movable element to both orientations of its field lines. By aligning with the field lines of the permanent magnet, the movable element switches between an open state or a closed state respectively corresponding to the opening or closing of an electric circuit.
• These magnetic microswitches sensitive to the orientation of the field lines react very accurately to the position of the permanent magnet. They are therefore difficult to adjust when assembling the detector.
• WO2004 / 066330 and US 5,923,523 disclose position sensors employing "reed" switches that are not very accurate, switched by the movement of a ferromagnetic part near a fixed magnet.
• the ferromagnetic part is set in motion by a fluid. Its displacement is not calibrated.
• the object of the invention is to provide an electrical switching device with a magnetic microswitch, whose adjustment during assembly is easy, whose performance is not affected over time, said device being precise and perfectly calibrated to trigger systematically when a force of specific intensity is applied.
• an electrical switching device comprising: a permanent magnet creating a magnetic field, an electric microswitch equipped with a movable element controlled by magnetic effect between at least two states by aligning following two different orientations of the field lines of the magnetic field of the permanent magnet, characterized in that: the microswitch and the permanent magnet are fixed with respect to each other, - the device comprises a mobile ferromagnetic part set in motion between two positions to act on the orientation of the field lines generated vis-à-vis the movable element by the permanent magnet in order to impose on the movable element one or other of its two states, in initial position, the ferromagnetic part is held by magnetic effect against the permanent magnet.
• using a permanent magnet and a microswitch fixed relative to one another limits the adjustment constraints of the operating points of the microswitch with respect to the permanent magnet and therefore of to overcome problems of assembly of the permanent magnet / microswitch couple.
• the permanent magnet thus serves both to retain the ferromagnetic part in the initial position but also to switch the microswitch during a movement of the ferromagnetic part.
• the movable ferromagnetic piece follows a translation movement.
• the translational movement is for example perpendicular to a direction of magnetization of the permanent magnet.
• the microswitch is for example centered with respect to the permanent magnet.
• the movable element is in a rest state situated between its open state and its closed state.
• the ferromagnetic part can be symmetrical and act, in each of its positions, symmetrically on the field lines of the permanent magnet.
• the ferromagnetic part in each of its positions, is maintained by a magnetic attraction effect exerted by the permanent magnet.
• the ferromagnetic part has a U-shaped shape comprising a central portion and two parallel wings between which the permanent magnet is positioned. In each position of the ferromagnetic part, one of its wings is attracted by the permanent magnet.
• the architecture of the invention is therefore particularly compact, in particular thanks to the double function of the magnet that allows both to switch the microswitch and maintain the ferromagnetic part in its initial position, and possibly, depending on the configuration, in its final position.
• the microswitch is for example off-center with respect to the permanent magnet. Without the influence of the ferromagnetic part, the microswitch is thus maintained by magnetic effect in one of its open or closed states.
• the ferromagnetic part can thus take a first extreme position in which it deflects the field lines to impose on the mobile element the other of its two states and a second far extreme position in which it does not act on the field lines. .
• the first extreme position is stable, the ferromagnetic part being maintained by magnetic attraction effect exerted by the permanent magnet and the second extreme position of the ferromagnetic part is ephemeral, marked by a stop. In the second extreme position, the ferromagnetic part remains under the magnetic influence of the permanent magnet so as to be recalled by magnetic effect to the first position.
• the permanent magnet is disk-shaped and the movable ferromagnetic piece has the shape of a rotating ring encircling the permanent magnet and performing a rotational movement around the permanent magnet.
• the ring has for example a protuberance adapted to take two diametrically opposite positions to act on the field lines on either side of a plane of symmetry.
• the switching device of the invention is for example used in a push button, a sliding button, a position switch, a shock sensor or an acceleration sensor.
• FIGS. 1 and 2 show the switching device of the invention, used in a sliding button, respectively in the closed state and in the open state
• FIGS. 3 and 4 show the influence of the ferromagnetic part on the magnetic field lines generated by the permanent magnet
• FIG. 5 represents the switching device employed in a rotating knob shown schematically, FIG. viewed from the side
• FIGS. 7 and 8 show the switching device of the invention used in a shock detector, respectively at rest and in the tripped state
• FIGS. 10 show the switching device of the invention employed in a shock detector, respectively in the idle state and in the triggered state
• FIG. 1 and 2 show the switching device of the invention, used in a sliding button, respectively in the closed state and in the open state
• FIGS. 3 and 4 show the influence of the ferromagnetic part on the magnetic field lines generated by the permanent magnet
• FIG. 5 represents the switching device employed in a rotating knob shown schematically, FIG. viewed from the side
• FIG. 11 represents in perspective a magnetic microswitch as used in the switching device. of the invention, Figures 12 and 13 show the microswitch of Figure 11 respectively in the open state and in the closed state according to the orientation of the general field lines es by a permanent magnet.
• the invention relates to a switching device comprising at least one fixed magnetic microswitch 2, a fixed permanent magnet 4, 40 and a movable ferromagnetic part 5, 50, 500.
• This switching device can be implemented in a push button, a sliding button or a rotary knob and in a position switch, a shock or acceleration sensor.
• the microswitch 2 used is of magnetic type, sensitive to the orientation of the field lines L of a magnetic field generated by a permanent magnet 4.
• This type of microswitch 2 can be switched by a permanent magnet between two states, an open state ( Figure 12) and a closed state ( Figure 13). It is for example manufactured in MEMS technology (for "Micro-Electro-Mechanical System”).
• FIGS. 11 to 13 An exemplary configuration of a microswitch 2 sensitive to the orientation of the field lines L is shown in FIGS. 11 to 13.
• a microswitch 2 sensitive to the orientation of the field lines L comprises a deformable ferromagnetic mobile membrane 20 which can be actuated in rotation about an axis of rotation (R) under the influence of the permanent magnet 4.
• the membrane 20 is for example made of Fer-Nickel.
• the membrane 20 has a longitudinal axis (A) and is connected, at one of its ends, via connecting arms 22a, 22b, to one or more anchoring studs 23 integral with a substrate 3.
• the membrane 20 is pivotable relative to the substrate along its axis (R) of rotation perpendicular to its longitudinal axis (A).
• the linking arms 22a, 22b form an elastic connection between the membrane 20 and the anchor pad 23 and are biased during the pivoting of the membrane 20.
• the membrane 20 At its distal end relative to its axis of rotation, the membrane 20 carries a movable contact 21.
• the membrane 20 can take at least two determined states, an open state (FIG. 12) in which two electrical tracks 31, 32 fixed on the substrate are disconnected or a closed state ( Figure 13) in which the two tracks 31, 32 are interconnected by the movable contact 21 carried by the membrane 20.
• Figure 1 the membrane is at the resting state, in a position parallel to the surface of the substrate 3.
• FIGS. 12 and 13 The operating principle of such a microswitch 2 is illustrated in FIGS. 12 and 13.
• One of the operating modes of the membrane 20 of such a microswitch 2 consists in applying a magnetic field created by a permanent magnet. 400.
• the ferromagnetic membrane 20 moves between its two states in alignment with the field lines L of the magnetic field generated by the permanent magnet 400.
• the field magnetic field of the permanent magnet 400 has L field lines whose orientation generates a magnetic component BP 0 , BP 1 in a ferromagnetic layer of the membrane 20 along its longitudinal axis (A).
• This magnetic component BP 0 , BP 1 generated in the membrane 20 generates a magnetic torque imposing on the membrane 20 to take one of its open states ( Figure 12) or closed ( Figure 13).
• the open or closed state of the membrane depends on the position and the orientation of the microswitch 2 relative to the permanent magnet 400.
• this principle of actuation of the microswitch 2 is used except that the permanent magnet 4, 40 employed and the microswitch 2 are both fixed.
• a ferromagnetic part 5, 50, 500 is set in motion between at least two positions near the magnet permanent 4, 40. In moving, this ferromagnetic part 5, 50, 500 has the effect of moving the plane of symmetry of the field lines L of the magnetic field of the permanent magnet 4, 40 and thus to deflect the field lines L of the permanent magnet 4, 40.
• FIGS. 1 and 2 A sliding button equipped with a switching device according to the invention is shown in FIGS. 1 and 2.
• This sliding button comprises an actuating member 6 integral with the ferromagnetic part 5 and movable in translation in a housing (not shown) next a direction of translation.
• the ferromagnetic part 5 is symmetrical with respect to a vertical plane and has for example an inverted U shape composed of two symmetrical parallel side wings 5a, 5b interconnected by a perpendicular central portion 5c.
• the permanent magnet 4 of the device is for example of parallelepipedal shape and is placed inside the U formed by the ferromagnetic part 5, between the two wings 5a, 5b of the part 5.
• the magnetization direction (M) of the permanent magnet 4 and the plane of symmetry of the field lines L of the permanent magnet 4 are perpendicular to the direction of translation of the movable ferromagnetic part 5.
• the translation direction of the ferromagnetic part 5 is for example located in a horizontal plane.
• the microswitch 2 is placed under the magnetic influence of the permanent magnet 4, centered with respect to the permanent magnet 5, so that without ferromagnetic part 5, the membrane 20 is parallel to the substrate 3 and is at the rest state (as in Figure 1 1).
• the axis of rotation (R) of the microswitch 2 is horizontal and perpendicular to the direction of translation of the ferromagnetic part 5.
• the ferromagnetic part 5 is able to move in translation between two extreme positions relative to the fixed permanent magnet 4. In each of its extreme positions, it comes for example abut by each of its wings 5a, 5b against the permanent magnet 4 and is held glued by magnetic attraction against the permanent magnet 4. A minimum effort must be exercised on the actuating member 6 for detaching the ferromagnetic part 5 from the permanent magnet 4 and moving it from one position to the other, thus giving the user a particular tactile effect when the body member is moved. 6.
• the magnetic attraction effect attenuates between a first wing 5a of the ferromagnetic part 5 and the permanent magnet 4 and increases between the second wing 5b of the ferromagnetic part 5 and the permanent magnet 4.
• the ferromagnetic part 5 has the effect of displacing the plane of symmetry of the field lines L of the permanent magnet 4. In each end position of the ferromagnetic part 5, L-field lines generated by the permanent magnet 4 are thus deflected. by the ferromagnetic part 5 so as to subject the membrane 20 of the microswitch 2 to a specific orientation and impose one of its open or closed states (see Figures 3 and 4).
• This configuration of the switching device in a sliding button is perfectly reproducible in a push button or a position switch, only the orientation of the parts to possibly be changed.
• the switching device according to the invention can also be used in a rotary knob as shown in FIG. 5.
• the rotary knob comprises, for example, a permanent magnet 40 in the form of a disc placed for example above the microswitch 2.
• the micro-switch 2 and the permanent magnet 40 are fixed relative to one another so that the membrane 20, without the influence of the ferromagnetic part 50, is at rest (as in FIG. 1 1).
• the ferromagnetic part 50 consists for example of a ring encircling the permanent magnet 40 and able to rotate about its axis around the permanent magnet 40 when it is actuated by an external actuating member not visible in FIG.
• the axis of the ring is for example vertical, while the axis of rotation of the membrane of the microswitch 2 is horizontal.
• the ring comprises an internal protuberance 51 formed in the direction of the permanent magnet 40 and charged as a function of the position of the ring to deflect the field lines of the permanent magnet 40.
• the protrusion 51 of the ring is able to rotate between at least two diametrically opposed positions (1 and 0 in FIGS. 5 and 6) aligned on the longitudinal axis (A) of the membrane 20 of the microswitch so as to deviate from one side or the other the lines of L-field of the permanent magnet and subject the membrane 20, depending on its position, to one or other of the two orientations of the field lines L.
• the configuration presented above of the switching device can also be used in a position switch, a shock or acceleration sensor, the actuation is no longer manual but caused by an external phenomenon.
• the switching device of the invention can also be used in a shock sensor or even an acceleration sensor.
• the shock sensor has for example a switching device similar to that used in the sliding button described above.
• the ferromagnetic part 5 is identical and thus has an inverted U shape with two parallel side wings 5a, 5b separated from a central portion 5c perpendicular.
• the permanent magnet 4 and the microswitch 2 are placed in the U formed by the ferromagnetic part 5.
• the first wing 5a of the ferromagnetic part in the initial position, the first wing 5a of the ferromagnetic part is held by magnetic effect against the permanent magnet 4 (FIG. 7).
• the ferromagnetic part 5 can be moved horizontally in one direction towards its second position, starting from a determined tripping threshold.
• the second wing 5b of the ferromagnetic part 5 is pressed against the permanent magnet 4 by magnetic effect (FIG. 8).
• the trigger threshold of the impact sensor is in particular a function of the mass of the movable ferromagnetic part 5, the nature of the materials constituting the permanent magnet 4 and the ferromagnetic part 5, the size of the surface of the permanent magnet 4 situated opposite the ferromagnetic part 5 as well as the initial gap distance separating the wing 5a, 5b distant from the ferromagnetic part 5 with respect to the permanent magnet 4.
• the ferromagnetic part 5 acts on the orientation of the field lines L of the magnetic field of the permanent magnet 4 so as to deflect them and to subject the membrane 20 of the microswitch 2 to a majority orientation
• the field lines L seen by the membrane 20 of the microswitch 2 impose its open state.
• the field lines L seen by the membrane 20 have an inverted orientation and impose its closed state.
• the ferromagnetic part 5 remains in a glued position to the permanent magnet 4 after the actuation of the shock sensor, which makes it possible to endow the sensor with a memory effect.
• the two wings 5a, 5b of the ferromagnetic part 5 can be dimensioned differently to increase the attraction force between the ferromagnetic part 5 and the permanent magnet 4 when the part 5 is in its second position.
• the distance between the permanent magnet 4 and the remote wing 5a of the ferromagnetic part 5 after the sensor has been triggered can be adjusted to prevent the return of the ferromagnetic part 5 to the initial position.
• the ferromagnetic part 500 has, for example, an L configuration with two perpendicular branches 501, 502.
• the ferromagnetic part 500 is displaceable in translation in one direction, for example horizontal, under the effect of a shock, between a stable initial position ( Figure 9) in which it is electromagnetically pressed against the permanent magnet 4 and a second remote position ( Figure 10).
• One of the branches 501 of the L-shaped ferromagnetic part 500 is perpendicular to its translation direction and the other branch is parallel to this direction.
• the second position is marked by a fixed abutment for example consisting of a wall 7 placed in the path of the ferromagnetic part 500.
• This wall 7 is positioned to maintain the ferromagnetic part 500 under the magnetic influence of the permanent magnet 4 regardless of the intensity of the shock, even when the ferromagnetic part 500 abuts against the wall 7. After an impact, the ferromagnetic part 500 is automatically reduced by magnetic effect against the permanent magnet 4.
• the microswitch 2 is off-center with respect to the permanent magnet 4 so as to put the membrane 20 in one of its two states, open or closed (closed in FIG. 10) when the ferromagnetic part 500 is in its second position (FIG. 10), that is to say when the ferromagnetic piece 500 is remote and has no effect on the field lines L of the permanent magnet 4.
• the ferromagnetic part 500 acts on the field lines L of the permanent magnet 4 and deflects them so as to subject the membrane 20 to a defined orientation and to impose the other of its two states, open or closed (open on the Figure 9).

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• Switches That Are Operated By Magnetic Or Electric Fields (AREA)
• Switches With Compound Operations (AREA)
• Executing Machine-Instructions (AREA)
• Hall/Mr Elements (AREA)
• Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

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• 2006
  • 2006-07-12 FR FR0652935A patent/FR2903807B1/fr not_active Expired - Fee Related
• 2007
  • 2007-07-02 CN CN2007800263382A patent/CN101490783B/zh not_active Expired - Fee Related
  • 2007-07-02 WO PCT/EP2007/056641 patent/WO2008006729A1/fr active Application Filing
  • 2007-07-02 US US12/373,372 patent/US8193884B2/en not_active Expired - Fee Related
  • 2007-07-02 EP EP07765758A patent/EP2041765B1/de not_active Not-in-force
  • 2007-07-02 AT AT07765758T patent/ATE556422T1/de active

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