Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/14—Pivoting armatures
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/13—Electromagnets; Actuators including electromagnets with armatures characterised by pulling-force characteristics
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/16—Rectilinearly-movable armatures
  • H01F7/1607—Armatures entering the winding
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H50/00—Details of electromagnetic relays
  • H01H50/16—Magnetic circuit arrangements
  • H01H50/36—Stationary parts of magnetic circuit, e.g. yoke
  • H01H50/42—Auxiliary magnetic circuits, e.g. for maintaining armature in, or returning armature to, position of rest, for damping or accelerating movement
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/081—Magnetic constructions
  • H01F2007/085—Yoke or polar piece between coil bobbin and armature having a gap, e.g. filled with nonmagnetic material

Definitions

• the present invention relates to a magnetic actuator intended for applications requiring long strokes and a large call force.
• the subject of the present invention is a magnetic actuator which overcomes the drawbacks of the prior art by providing a more efficient device, that is to say making it possible to obtain either a calling force during the significantly higher power on for an equivalent stroke or a higher stroke for the same call force.
• a magnetic actuator ensuring, under the effect of the excitation of a magnetic circuit, the bonding of a moving part against a pole piece from which it is separated by an air gap, characterized in that it comprises in addition at least one intermediate part arranged in this air gap and able to move between the moving part and the pole piece, while defining in the absence of excitation (at rest) free spaces el, e2, e3 between the or the intermediate parts and respectively the moving part and the pole piece, which spaces constitute air gaps for the magnetic flux.
• the actuator according to the invention comprises two intermediate parts, these define at rest a first air gap el between the pole piece and the first intermediate part, a second air gap e2 between this intermediate part and the second intermediate part and a third air gap e3 between the second room intermediate and moving part.
• a part made of a non-magnetic material is intended to maintain the intermediate part or parts in the rest position in which this or these intermediate parts as well as the pole piece and the moving part are fixed and separated by said air gaps.
• a magnetic actuator intended for controlling a shaft for transmitting a movement and provided with a magnetic circuit, the excitation of which tends to cause a movable core to stick against a pole piece from which it is separated. by an air gap, may further comprise at least one intermediate piece disposed in this air gap and able to move between the core and the pole piece while defining at least two air gaps with these two elements, in the absence of excitation of the magnetic circuit .
• such an actuator comprises a tubular magnetic circuit inside of which are arranged coaxially both a movable core and a fixed pole piece while defining between these two coaxial elements a first space in the axial direction, the core and the pole piece being drilled along their longitudinal axis to receive a motion transmission shaft, characterized in that the external diameter of the shaft has a larger dimension on an end part extending over a part of the inner wall of the pole piece so that a complementary annular space is created between the outer surface of the non-oversized shaft and the part of the wall of the pole piece which is not in contact with this shaft, this complementary space that can receive an annular T-shaped intermediate piece whose base of larger diameter extends in said first space and which is free to slide on the one hand internally along the shaft and on the other hand externally along the pole piece.
• the intermediate piece comprises on the peripheral surface of its base a shoulder intended to come into abutment against a corresponding shoulder of a ring made of a non-magnetic material and arranged in the first space against the internal wall of the magnetic circuit.
• the T-shaped intermediate piece is replaced by a Y-shaped intermediate piece with a base with conical surfaces, it is the end of this base which is intended to abut against a shoulder of this ring.
• the shaft has a shoulder cooperating with a complementary shoulder of the core so that transmission of the movement between these two elements can be achieved.
• the shaft comprises over a part of its length in contact with the core with an outer diameter of smaller dimension corresponding with an equally reduced diameter of this core.
• a metal carcass covers the external surfaces of the magnetic circuit and of the pole piece as well as a part of the internal wall of this magnetic circuit arranged opposite the core.
• the shaft In the absence of excitation of the magnetic circuit, the shaft is subjected to a restoring force obtained by the action of a spring, one end of which is integral with this shaft and the other end of which bears on an external wall. of the actuator.
• the present actuator is particularly suitable for the production of solenoid valves such as for example magnetic cylinders.
• FIG. 1 shows an example of a solenoid valve provided with a magnetic actuator according to the invention
• FIGS. 2, 3 and 4 show the magnetic circuit of the actuator of FIG. 1 in three distinct operating positions: at rest, in an intermediate position and when glued,
• FIG. 5 is a first alternative embodiment of the magnetic actuator according to the invention having conical contact surfaces
• FIG. 6 is a second alternative embodiment of the magnetic actuator according to the invention having two intermediate parts
• Figure 1 shows an exemplary embodiment of a two-way solenoid valve provided with a magnetic actuator according to the invention.
• This solenoid valve comprises on the one hand a cylindrical body 10 intended to receive the actuator and on the other hand inlet 12 and outlet 14 channels connected to one end of this body and communicating with a central chamber 16 in which is formed a seat 18 of a valve 20.
• the actuator is held in the body 10 by means of a non-magnetic cylindrical jacket 22 forming a receptacle and a cover 24, the receptacle-cover assembly being secured, for example, by a nut 26.
• the actuator is traversed along its longitudinal axis by a motion transmission shaft 28 which is integral with a push rod 30 on which the valve 20 is mounted.
• a return spring 32 which bears on an external face of the jacket 22 allows the positioning of the shaft in rear mechanical stop in an extreme low position (rest position of the actuator) in which the valve rests on its seat.
• the actuator is in the form of a magnetic circuit, comprising a tubular electric circuit 34 implanted in a magnetic part 40, and inside which are coaxially arranged both a movable core 36 and a fixed pole piece 38 while leaving between these two coaxial elements a first free space in the axial direction.
• the core 36 and the pole piece 38 are drilled along their longitudinal axis to receive the shaft 28 for transmitting the movement which is non-magnetic.
• the outer diameter of the shaft 28 has a larger dimension on an upper end portion 28a extending over an upper portion of the inner wall of the pole piece 38 so that there is a complementary annular space 37 between the external surface of the shaft 28 of non-oversized medium section 28b and the part of the wall of the pole piece 38 which is not in contact with this portion of shaft 28b of medium section, which portion 28b has a corresponding external diameter to the internal diameter of the movable core 36.
• the part 40 covers the external surfaces of the electrical winding 34 and of the pole piece 38 as well as a part of the internal wall of this tubular circuit 34 disposed opposite the core 36.
• annular intermediate piece 42 in the shape of a T (overturned or not depending on the arrangement elements of the actuator) whose horizontal branch or the larger diameter base 42a extends in the first space existing axially between this pole piece 38 and the core 36.
• This piece 42 which must be able to ensure continuity magnetic and is therefore made for example of a ferromagnetic material, is free to slide on the one hand internally along the portion 28b of the shaft 28 and on the other hand externally along the pole piece 38.
• the surface peripheral of the base 42a of the intermediate piece 42 comprises a shoulder 42b intended to come into abutment against a corresponding shoulder 44b of a ring 44 made of a non-magnetic material and disposed against the internal wall of the electrical circuit 34 in the space separating axially the pole piece 38 of the core 36.
• the internal diameter of the lower part 44a of this ring 44 corresponds to the external diameter of the core 36 to constitute a oi guiding the latter during its movement under the action of the magnetic field created in the actuator.
• the intermediate piece 42 which is inserted into the magnetic circuit consisting of the pole piece 38, the magnetic piece 40 of the electric winding and the core 36 defines at rest along the longitudinal axis of the actuator of the air gaps el and e2 between the piece intermediate 42 and respectively the core 36 and the pole piece 38.
• the core 36 is in an extreme low position, its lower face pressed (with the exception of a slight clearance intended to ensure the support of the valve 20) against the bottom of the receptacle 22 by the shaft 28 which passes through it , is subjected directly to the return force of the spring 32 and has a shoulder 28c cooperating with a complementary shoulder 36c of the core 36 (these shoulders can be very simply made by reducing the diameter of the shaft 28 and of the core 36 on part of the length of the nucleus).
• the intermediate piece 42 pushed by the shaft 28 is in abutment on the internal shoulder 44b of the ring 44 so that there can remain the air gap el between the external radial face of its base 44a and the radial upper face of the core 36.
• the actuator in this operating phase, behaves like a conventional magnetic circuit having the sole air gap el and therefore it will generate an attractive force between the core 36 and the intermediate piece 42 which tends to reduce this air gap el.
• This reduction and then the complete disappearance of the air gap causes a considerable increase in the flow passing through the intermediate piece 42.
• Figures 5 to 12 Other embodiments of the actuator according to the invention are shown in Figures 5 to 12.
• Figure 5 which shows the actuator in a high bonding position
• the intermediate piece 42 has a Y shape with a conical base 42d, the end of which is initially in abutment against the shoulder 44b of the ring 44 made of non-magnetic material.
• the operation of this actuator is strictly identical to that described above with reference to FIGS. 2 to 4, the presence of the conical contact surfaces however making it possible to obtain a greater stroke with identical air gaps or the same stroke with weaker air gaps.
• FIG. 6 illustrates, in an initial rest position, another embodiment of the actuator according to the invention in which the free space in the axial direction existing between the pole piece 38 and the movable core 36 comprises not only a but two intermediate parts 42 and 43.
• the relay effect of the magnetic flux generated by these parts can be extended to more than two air gaps, thereby lengthening the stroke of the actuator, without any significant loss of appeal force.
• the first intermediate piece 42 has a T shape with a base 42a whose peripheral surface rests on a first shoulder 44b of the ring non-magnetic 44 and thus defines, as before, the air gap el between the external radial face of this base and the upper face of the core 36.
• the first intermediate part 42 is free to slide on the one hand internally along the shaft 28 and on the other hand externally along an internal cylindrical face 43a of the second intermediate part 43.
• this second part 43 can itself also slide internally along the shaft 28 (on a part 28d of slightly larger diameter at the average diameter of this shaft on which the part 42 can slide) and externally, by a part of its external cylindrical face 43b, along both the ring 44 and an internal lateral face of the pole piece 38.
• a second shoulder 44c is formed in this ring 44 to constitute a stop for the second intermediate part 43 and to define at rest the second air gap e2 between the internal radial face of the base 42a and the external radial face of the second part 43.
• a third air gap e3 is present between the internal radial face of the second intermediate part 43 and the external radial face of the pole piece 38, maintaining, in its rest position, this second part 43 being obtained by the action of the end part of the shaft of greater dimension 28a on a part of its internal radial face.
• the actuator behaves like a conventional magnetic circuit having the sole air gap el and it will therefore generate an attractive force between the core 36 and the first intermediate part 42 which tends to reduce this first air gap.
• This reduction then the complete disappearance of the air gap (by gluing the core against the first intermediate part) causes a considerable increase in the flux passing through the first part 42.
• a new attraction force is then created between the two intermediate parts, making it possible to reduce until its disappearance the space e2 separating them and also causing magnetic saturation of the second intermediate part with the consequence of a deflection of the flow by the third air gap e3 formed between the internal radial face of the second intermediate part 43 and the external radial face of the pole piece 38.
• a new force of attraction will then arise and cause the gradual disappearance of the latter air gap.
• FIGS. 7 to 9 illustrate the application of the invention to actuators with
• the calling force as the stroke can be advantageously increased by the addition of one or more intermediate parts serving as relays to the magnetic flux and arranged in the air gap existing between the moving part 66 and the pole piece 68.
• the movable piece (the pallet 66) is articulated with the pole piece 68 that surrounds the magnetic coil 60. Means for retaining this movable piece, not shown, allow, in the initial rest position of Figure 7, keep the magnetic circuit open by creating a restoring force F on the pallet.
• an intermediate piece 62 articulated on the movable piece 66 rests on a shoulder 64b of a piece made of a non-magnetic material 64 by defining a first air gap between the intermediate piece and the pole piece and a second air gap e2 between this intermediate piece and the moving piece.
• Alternative solutions can result from the elimination of the part 64 and the installation of a device for limiting the angular travel of the intermediate part 62 relative to the moving part 66.
• this actuator can be simply described as follows.
• the magnetic winding 60 When the magnetic winding 60 is energized, the magnetic flux passes through the intermediate part 62 by the joint articulation with the moving part 66 and tends to reduce the air gap existing between this part and the pole piece 68. The latter reduces , the part 62 is then quickly saturated by the magnetic flux, the action of which will accentuate the tilting of the moving part by filling the second air gap e2 and thus causing the complete closure of the actuator (FIG. 9).
• FIGS. 10 to 12 illustrate another application of the invention to more conventional actuators of the "relay" type in which the structure of the invention makes it possible to increase the stroke without reduction in performance.
• FIG. 10 shows a conventional structure with a pole piece 78, a movable core 76 and a magnetic coil 70.
• the movable piece 76 is separated by an air gap e from the pole piece 78 by the action of a restoring force F.
• the moving part is provided with an intermediate piece in the shape of a stirrup 72 placed in the air gap e and the branches 72a of which can slide along the piece 76 while the floor 72b of this stirrup defines air gaps el and e2 respectively with the pole piece 78 and the moving piece 76.
• a piece 74 of a non-magnetic material is placed at the end of the moving piece 76 in order to serve as a stop at rest for the intermediate piece 72.
• this actuator is similar to the previous one.
• the flux created between the moving part and the pole piece passes through the intermediate piece 72 (by the lateral contacts between the arms of the bracket 72 and the moving piece 76) and tends to reduce the 'air gap existing between the latter and the pole piece.
• the part 72 becomes magnetically saturated and the magnetic flux then tends to reduce the second air gap e2 to result in the configuration of FIG. 12 in which the moving part is found glued against the pole piece by the middle of room 72.
• the force of attraction is from 50 to more than 100% greater than that recorded by a conventional actuator.
• the actuator stroke can be lengthened by 30 to 100% depending on the case.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Electromagnets (AREA)
• Reciprocating, Oscillating Or Vibrating Motors (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9470274

Family Applications (1)

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Family Cites Families (2)

• 1994
  • 1994-12-27 FR FR9415694A patent/FR2728721B1/fr not_active Expired - Lifetime
• 1995
  • 1995-12-22 WO PCT/FR1995/001723 patent/WO1996020488A1/fr active IP Right Grant
  • 1995-12-22 DE DE69517308T patent/DE69517308T2/de not_active Expired - Lifetime
  • 1995-12-22 EP EP95943267A patent/EP0752152B1/de not_active Expired - Lifetime

Non-Patent Citations (1)

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