EP0653097B1 - Kontrollmechanismus mit Verriegelungsmagnet - Google Patents

Kontrollmechanismus mit Verriegelungsmagnet Download PDF

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Publication number
EP0653097B1
EP0653097B1 EP94915843A EP94915843A EP0653097B1 EP 0653097 B1 EP0653097 B1 EP 0653097B1 EP 94915843 A EP94915843 A EP 94915843A EP 94915843 A EP94915843 A EP 94915843A EP 0653097 B1 EP0653097 B1 EP 0653097B1
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EP
European Patent Office
Prior art keywords
core
lever
coil
saturation region
electromagnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94915843A
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English (en)
French (fr)
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EP0653097A1 (de
Inventor
C. Nickolas Goloff
Rodney L. Rolffs
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
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Caterpillar Inc
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Publication date
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    • 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
    • H01F7/121—Guiding or setting position of armatures, e.g. retaining armatures in their end position
    • 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
    • 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
    • H01F7/14—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
    • H01F7/16—Rectilinearly-movable armatures
    • H01F7/1638—Armatures not entering the winding

Definitions

  • This invention relates to a control mechanism with an electromagnet comprising a core that operates with a portion of the core in magnetic saturation.
  • Latching electromagnets are used in a variety of applications.
  • a control circuit may require that an electromagnet "latch” a moveable member to a detent position. Further, the control circuit may also require that the moveable member be “de-latched” from the detent position by a mechanical device that provides a predetermined force. However if the "latching" force of the electromagnet varies, then the mechanical device may not have sufficient force to overcome the electromagnetic force. Consequently the moveable member remains latched to the detent position, possibly causing the control system to malfunction.
  • an electromagnet may be provided to latch a control lever of an electrohydraulic control at a detent position.
  • the control lever is latched at the detent position until; either the electromagnet de-energizes, or an operator manually de-latches the control lever from the energized electromagnet. If the later occurs, the operator must apply a force to the control lever that overcomes the electromagnetic force.
  • a prior electromagnet 100 is shown in Fig. 1.
  • the electromagnet 100 includes a core 105, a coil 110 and an armature 115.
  • the coil 110 Upon being energized, the coil 110 produces an electromagnetic force which "latches" the armature 115 to the core 105.
  • a spring 120 biases the armature to a neutral position.
  • Fig. 2 Shown in Fig. 2, is a Force vs. Current curve which illustrates the relationship between the electromagnetic force and the coil current (when the armature is latched to the core).
  • the coil current fluctuates between a minimum and maximum value.
  • the current fluctuation is caused by changes in coil temperature and voltage. Due to the "steepness" of the curve, the resulting electromagnetic force may vary between a force that is too small - allowing for inadvertent de-latching of the control lever; to a force that is too large - yielding a force too great for the operator to overcome.
  • the armature 115 is designed to latch "flush" with the electromagnetic core.
  • the air gap length may vary, which in turn varies the electromagnetic force.
  • manufacturing tolerances, misalignment of the core/armature, and foreign materials that accumulate on the electromagnet parts (such as dust and rust particles), all may significantly vary the length of air gap.
  • Significant variations in the air gap combined with coil current fluctuations make for difficult electromagnetic force controllability.
  • FIG. 3 illustrates a cross section of a cylindrical latching electromagnet 300.
  • the electromagnet 300 includes a core 305 having a pole face, and inner and outer portions 310,315 that are separated by a channel 320.
  • a coil 325 of windings is disposed in the channel 320. Upon energization of the coil 325, the coil 325 produces an electromagnetic force that causes an armature 330 to latch to the pole face.
  • the electromagnet 300 is designed with a geometrical configuration formed at the core to locally increase the flux density to saturation levels.
  • Shown in Fig. 4 is a typical B-H curve associated with the electromagnets of this type.
  • the y-axis represents the magnetic flux density, B, while the x-axis represents the magnetic flux intensity or field strength, H.
  • the portion of the curve that is above (Bsat) represents the saturated magnetic flux density region.
  • the magnetic saturation region corresponds to a B-H relationship that naturally occurs in air.
  • FIG. 3 One type of a geometrical configuration is shown in the embodiment of Fig. 3, where the core 305 defines a saturation region 335 on the inner portion 310 to provide for a saturated magnetic flux density. More particularly, the core 305 defines a bore 333 at the inner portion 310.
  • the predetermined area of the saturation region 335 provides for little variation in magnetic flux density and electromagnetic force - even with changes in coil current and temperature.
  • the resulting Force vs. Current curve is described in Fig. 5.
  • the desired electromagnetic force operates about a predetermined operating point.
  • the part of the curve corresponding to the predetermined operating point is relatively “flat” as compared to the operating point associated with prior art electromagnets.
  • coil current fluctuations produce only small changes in electromagnetic force, as compared to the prior art electromagnets.
  • the outer portion 315 is greater in length than the inner portion 310 to create a predetermined working air gap length, L g , between the inner portion 310 and the armature 330 (when the armature 330 is latched to the pole face).
  • the predetermined air gap length, L g is substantially greater than the relative increase of the air gap length due to poor alignment, wear, foreign material, etc.
  • the predetermined air gap length, L g provides for small changes in the electromagnetic force due to changes in the air gap length caused by armature/core misalignment.
  • the present invention may be used in a variety of applications, one such application in Fig. 7.
  • the present invention is used to "latch" a control lever of a control mechanism at a detent position.
  • the control mechanism 700 includes a housing 705 and a control lever 710 disposed in the housing 705.
  • the control lever 710 has bi-directional, pivotal movement between a neutral and a predetermined position (on either side of neutral).
  • the control lever 710 is bifurcated and defines two arms 715.
  • An electromagnet armature 330 is rigidly mounted to each lever arm 715.
  • a centering spring 720 is attached to the bifurcation to bias the control lever 710 to the neutral position. The operation of the present invention in relation to the control mechanism 700 will be discussed infra.
  • the present invention additionally provides for a self-aligning, mounting feature to compensate for the manufacturing tolerances or for poor alignment of the outer pole face with the armature.
  • the electromagnet 300 is shown mounted to a mounting plate 800.
  • a bolt 805 is used to fasten the electromagnet core 305 to the mounting plate 800.
  • Two O-rings 810a,b composed of flexible material are also provided.
  • One O-ring 810a is disposed between a washer 815 and the mounting plate 800, while the other O-ring 810b is disposed between the mounting plate 800 and the electromagnet core 305.
  • the illustrated configuration provides a certain degree of flexibility to the mounting of the electromagnet. For example as shown in Fig.
  • the alignment of the armature 330 is "skewed" in relation to the x-axis and would not "mate” properly with a rigidly mounted electromagnet core.
  • the mounting is flexible which allows for the armature 330 to properly mate with the electromagnet core 305 irrespective of the armature orientation.
  • FIG. 10 Another type of a self aligning feature is shown in Fig. 10.
  • the electromagnetic core 330 includes a flange 820
  • the mounting plate 800 includes a mechanical joint 825 for griping the flange 820 to secure the electromagnetic core 330 to the mounting plate 800.
  • this feature also provides for mounting flexibility. For example as shown in Fig. 11, the misaligned armature 330 is properly mated with the electromagnet core 305.
  • the core 305 defines a saturation region 335 on the outer portion 315 to provide for a saturated magnetic flux density. More particularly, the core 305 defines an annular groove 337 on the outer core surface.
  • This geometrical configuration provides for several advantages. Because the pole faces are not modified to create the saturation region, the surface areas of the pole faces may be relatively large to yield a relatively high latching force. Moreover, this configuration produces negligible variations in magnetic flux density and electromagnetic force.
  • the operation of the present invention may be used in an implement control system of a work vehicle. Although an implement control system is described, it will be apparent to those skilled in the art that the present invention may be used in a variety of applications where "latching" is desired.
  • the present invention may provide for "automatic" control of a work implement of the vehicle.
  • the electromagnet 330 "latches” the control lever 710 at a predetermined lever position, which represents a predetermined position of the work implement, e.g. a predetermined bucket "lift” or "angle".
  • the vehicle operator pivots the control lever 710 to a predetermined position.
  • a driving circuit 725 delivers an energization signal to the electromagnet 300 which responsively energizes and "latches" the control lever 705 at the predetermined lever position.
  • an electrohydraulic system positions the work implement to a predetermined position. Once the work implement reaches the predetermined position, the implement control system may then de-energize the electromagnet 300 to cause the control lever 710 to de-latch from the electromagnet 300.
  • the spring 720 then biases the control lever 710 to the neutral position.
  • the present invention provides for a predetermined electromagnetic force that is large enough to overcome the spring force of the spring 720 but small enough to be overcome by the force applied by the vehicle operator. Further, the present invention provides that the predetermined electromagnetic force to remain substantially constant (even when driven with a fluctuating coil current).
  • the electromagnetic force remains within a predetermined force range to provide a substantially constant force level that prevents inadvertent de-latching caused by the electromagnetic force falling below the spring force, and also prevents the electromagnetic force from becoming too large to be manually exceeded by an operator.
  • This feature enables the electromagnet to be used in a variety of control systems wherein a constant electromagnetic force is desired.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnets (AREA)

Claims (4)

  1. Steuermechanismus, der folgendes aufweist: ein Gehäuse (705); einen am Gehäuse (705) befestigten Verriegelungs-Elektromagneten (300), der folgendes aufweist: einen eine Polfläche definierenden Kern (305), eine im Kern (305) angeordnete Spule aus Windungen (325), und einen Anker, wobei der Kern eine Sättigungszone (335) definiert zum Vorsehen einer gesättigten magnetischen Flußdichte, gekennzeichnet durch einen im Gehäuse (705) angeordneten Hebel (710) mit einer Schwenkbewegung zwischen einer neutralen und einer vorbestimmten Position, wobei der Hebel (710) einen Arm (715) vorsieht, und ferner gekennzeichnet dadurch, daß der Anker (330) starr am Arm (715) angebracht ist, und ferner gekennzeichnet dadurch, daß die Sättigungszone eine Querschnittsfläche A mit der folgenden Beziehung besitzt: A = π 4 x ( D o 2 - D i 2 )
    Figure imgb0007
     wobei D0 den Außendurchmesser der Sättigungszone representiert und Di den Innendurchmesser der Sättigungszone darstellt; und ferner gekennzeichnet durch Mittel (725) zur Lieferung elektrischer Energie an die Spule (325), ansprechend auf den in einer vorbestimmten Position positionierten Hebel (710), wobei die Spule (325) in darauf ansprechender Weise erregt wird und eine elektromagnetische Kraft erzeugt, die den Hebel (710) dazu veranlaßt, in der vorbestimmten Position zu verriegeln.
  2. Steuermechanismus nach Anspruch 1, wobei der Kern (305) eine Kreisform besitzt und radial innere und äußere Teile (310, 315), getrennt durch einen Ringkanal (320), definiert, wobei der Kern (305) ferner eine Ringnut (337) definiert, die an der Außenoberfläche des Kerns angeordnet ist, um eine gesättigte Magnetflußdichte vorzusehen, wobei die Sättigungszone (335) zwischen der Ringnut (337) und dem Ringkanal (320) angeordnet ist.
  3. Steuermechanismus nach Anspruch 1 oder 2, wobei die erregte Spule (325) eine im wesentlichen konstante elektromagnetische Kraft erzeugt.
  4. Steuermechanismus nach einem der vorhergehenden Ansprüche einschließlich einer Zentrierfeder (720), verbunden mit dem Hebelarm (715), wobei die Zentrierfeder (720) den Hebel (710) in die Neutralposition vorspannt, und zwar ansprechend auf die Enderregung der Spule (325).
EP94915843A 1993-06-01 1994-04-20 Kontrollmechanismus mit Verriegelungsmagnet Expired - Lifetime EP0653097B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US6979793A 1993-06-01 1993-06-01
US69797 1993-06-01
PCT/US1994/004372 WO1994028559A1 (en) 1993-06-01 1994-04-20 Latching electromagnet

Publications (2)

Publication Number Publication Date
EP0653097A1 EP0653097A1 (de) 1995-05-17
EP0653097B1 true EP0653097B1 (de) 1997-12-17

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EP94915843A Expired - Lifetime EP0653097B1 (de) 1993-06-01 1994-04-20 Kontrollmechanismus mit Verriegelungsmagnet

Country Status (4)

Country Link
EP (1) EP0653097B1 (de)
JP (1) JPH07509815A (de)
DE (1) DE69407387T2 (de)
WO (1) WO1994028559A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5114506B2 (ja) * 2007-03-23 2013-01-09 オーチス エレベータ カンパニー エレベータシステムの磁気式連結装置
DK2280803T3 (da) * 2008-04-22 2012-10-15 Tecnomagnete Spa Monolitisk magnetindretning og fremgangsmåde til fremstilling af den monolitiske magnetindretning

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3517360A (en) * 1966-07-14 1970-06-23 Bell Aerospace Corp Electromagnetic force motor having linear output characteristics
US3571769A (en) * 1969-05-08 1971-03-23 Bell Aerospace Corp Electromagnetic force motor having adjustable magnetic saturation
US3644932A (en) * 1969-10-08 1972-02-22 Synergistics Inc High-speed indenting recorder
US3861643A (en) * 1973-10-05 1975-01-21 United Aircraft Corp Saturating magnetic control valve
GB1509907A (en) * 1974-08-14 1978-05-04 Lucas Industries Ltd Electro-magnetic actuating devices
US3921111A (en) * 1974-09-25 1975-11-18 Marotta Scientific Controls Solenoid actuator for high pressure valve
JPS606526B2 (ja) * 1980-04-15 1985-02-19 ブラザー工業株式会社 ロ−タリソレノイド
US4419642A (en) * 1982-01-28 1983-12-06 Deere & Company Solenoid with saturable element
US4812884A (en) * 1987-06-26 1989-03-14 Ledex Inc. Three-dimensional double air gap high speed solenoid

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Publication number Publication date
DE69407387T2 (de) 1998-07-16
EP0653097A1 (de) 1995-05-17
WO1994028559A1 (en) 1994-12-08
DE69407387D1 (de) 1998-01-29
JPH07509815A (ja) 1995-10-26

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