|Publication number||US3460081 A|
|Publication date||Aug 5, 1969|
|Filing date||May 31, 1967|
|Priority date||May 31, 1967|
|Publication number||US 3460081 A, US 3460081A, US-A-3460081, US3460081 A, US3460081A|
|Original Assignee||Marotta Valve Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (50), Classifications (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Aug. 5, 1969 A. TILLMAN 3,460,081
ELECTROMAGNETIC ACTUATOR WITH PERMANENT MAGNETS Filed May 51. 1967 ATTORNEYS.
United States Patent 9 Claims ABSTRACT OF THE DISCLOSURE A bi-stable electrically operated actuator suitable for use with valves, switches, or any other device that must be moved between positions at opposite ends of a stroke, and that must be held in position, selectively, at either end of the stroke. The actuator has two permanent magnets, one for holding it in each position, and it has electromagnetic windings that are temporarily energized to shift the movable element of the actuator from one position to the other. The movable element is a plunger which is made of material that is attracted by a magnet, but it is not itself a permanent magnet and it does not carry any of the windings. The preferred embodiment operates without requiring any reversal of the polarity of any of the magnetic poles of the actuator.
Brief description of the invention The invention is an improved bi-stable solenoid of the type which has a plunger that is held, selectively, at either end of its stroke by permanent magnets; and that requires energization only during the time that the plunger is moving between different ends of its stroke.
The plunger is not itself a magnet, but it is made of material which is attracted by magnets. There is a different electromagnetic coil for moving the plunger in each direction. Although the permanent magnets are located at opposite ends of the plunger stroke, the stroke is long enough so that the distance from the disengaged magnet is sufiicient to prevent that magnet from adversely affecting the holding power of the permanent mag net by which the plunger is held at any particular time The actuator is constructed so that the permanent magnets do not have direct contact with the plunger and are not subject to direct shocks resulting from snap action of the plunger.
Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.
Brief description of the drawing In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views:
FIGURE 1 is a sectional view through :an actuator made in accordance with this invention; and
FIGURES 2 and 3 are sectional views, on a reduced scale, taken on the lines 2-2 and 3-3, respectively, of FIGURE 1.
Detailed description of the invention FIGURE 1 shows an actuator including a housing which comprises a core 12 with a cylindrical opening 14 extending throughout the full length of the core and preferably coaxial with the core. There is a pole piece 16 in the left-hand end of the cylindrical opening 14; and a corresponding pole piece 18 in the right-hand end of the cylindrical opening. Each of these pole pieces 16 and 18 is preferably a press fit in the core 12; and each "ice of the pole pieces may have a cylindrical bearing surface 20, coaxial with the opening 14.
The movable element of the actuator is a plunger 22 which slides freely in the cylindrical opening 14 between confronting end faces 24 of the pole pieces 16 and 18. The plunger 22 contacts with the end face of the pole piece 16 at one end of the stroke of the plunger, and with the end face 24 of the pole piece 18 at the other end of the stroke. Thus the stroke of the actuator 10 is determined by the spacing of the pole pieces 16 and 18 from one another.
The end faces of the plunger 22 are of complementary contour to the end faces 24 of the pole pieces 16 and 18. In the construction illustrated, these faces are frustoconical, but it will be understood that they can be flat or stepped, depending upon the desired shape of the power curve of the actuator.
There is an actuator shaft 28 connected with one end of the plunger 22. The drawing shows the shaft 28 with threads 30 that screw into the plunger 22. This is merely representative of a connection between the shaft and plunger, and these parts can be of one piece construction, if desired. The actuator shaft 28 slides axially in the pole piece 16.
At the other end of the plunger 22, the drawing shows another actuator shaft 28', which is connected with the plunger 22 in the same way as the actuator shaft 28, and which slides axially in the pole piece 18. If the actuator is intended for a use requiring only one actuator shaft, the other actuator shaft 28 or 28' can be omitted. The plunger 22 is shown with a uniform diameter between its end faces, but this is not essential, and the mid portion of the plunger 22 can be of reduced diameter to decrease the friction surface, or the plunger can be made in two portions connected together by a threaded element.
The core 12 has circumferentially extending cut-out portions in which electromagnetic windings 32 and 34 are located. Beyond these coils or windings 32 and 34 there are annular permanent magnets 36 and 38, respectively. In the construction shown, the magnets 36 and 38 are beyond the outer circumference of the coils 32 and 34 with the poles of each magnet axially spaced from one another, but these magnets can be beyond the ends of the coils with their poles in radial relation to one another. The core 12, pole pieces 16 and 18, and the plunger 22 are made of ferrous material, or other material which is a good conductor of magnetic flux.
The annular permanent magnets 36 and 38 are preferably of one-piece construction. There is preferably a ring 46, also of one-piece annular construction, for holding the magnets 36 and 38 in spaced relation to one another. An end ring 48 is preferably pressed over the end of the core 12 to hold the magnets 36 and 38, and the ring 46 against axial displacement.
The rings 46 and 48 are preferably of ferrous material so as to constitute a part of the magnetic circuit of the core 12. The electromagnetic windings 32 and the permanent magnet 36 are located so that their poles are effectively at opposite sides of the gap between the plunger 22 and the end face 24 of the pole piece 16 when the plunger is at the right-hand end of its stroke. Similarly, the electromagnetic windings 34 of the permanent magnet 38 effectively span the gap between the other end of the plunger 22 and the end face 24 of the pole piece 18 when the plunger 22 is at the left-hand end of its stroke.
In order to spread the magnetic flux and to concentrate it in the confronting faces of the plunger and pole pieces 16 and 18, there are sections of non-magnetic material 52 inserted in the core 12 adjacent to the gaps between these confronting faces. The sections 52 preferably span the gaps.
With the parts in the position shown in FIGURE 1,
the plunger 22 is held in contact with the end face 24 of the pole piece 18. When winding 34 is not energized, the magnetic circuit is from the permanent magnet 38, through ring 48 (if used), through core 12, pole pieces 18, plunger 22, through ring 46 (if used) and the other end of magnet 38. Although there is a similar magnetic circuit at the other end of the plunger, the gap between the plunger and the pole piece 16 is sufficient to weaken this other magnetic circuit so that it does not detract substantially from the holding power of the magnetic flux at the right-hand end of the plunger 22.
The plunger 22 will remain in this position without expenditure of any electrical energy, until the winding 32 is energized to move the plunger toward the left. When this winding 32 is energized, it adds so much additional flux to the magnetic circuit of the magnet 36 that the combined pull of the magnet 36 and the electromagnet formed by the windings 32 is sufficient to overcome the holding power of the permanent magnet 38, and the plunger 22 is moved to the left-hand end of its stroke. The supply of energy to the windings 32 is then shut off, but the plunger 22 remains in position at the right end of its stroke as a result of the attraction of the permanent magnet 36.
Return movement of the plunger 22 to the right end of its stroke can be effected at any time by energizing the winding 34 which adds to the pull of the magnet 38 sufliciently to overcome the holding power of the permanent magnet 36.
In the construction illustrated, the plunger 22 has direct contact with the end faces of the pole pieces 16 and 18; but non-magnetic gaskets or facing can be used to produce a small magnetic gap between the ends of the plunger and the end faces of the pole pieces 16 and 18, if desired, while still leaving the end faces as the ultimate mechanical stops for limiting the stroke of the plunger 22.
From the description of the operation, it will be apparent that the plunger 22 moves with snap action. This is highly desirable for operating either valves or switches. The shock of the plunger in striking the stops, provided by the faces 22, at each end of the stroke, is not a direct shock on the permanent magnets 36 and 38. This protects the magnets and is an advantage over constructions which require that the plunger be a permanent magnet, or that the plunger strike against permanent magnets. The invention provides a bi-stable solenoid-operated actuator which is firmly held in position at either end of its stroke and without requiring the energizing of the actuator coils at any time except when the plunger is being moved.
The apparatus can also be operated by Supplying current to the magnet coil at the end of the apparatus at which the plunger 22 is in contact with the pole piece 16 or 18 and with the current in a direction to set up an opposing flux that nullifies the fiux of the permanent magnet so that less force is required to move the plunger. In some designs the permanent magnet at either end can be made strong enough to shift the plunger when the flux of the permanent magnet at the other end is nullified by its associated coil 32 or 34.
The preferred embodiment of the invention has been illustrated and described, and the invention is defined in the claims.
What is claimed is:
1. In a bi-stable electromagnetic actuator including a core having an axial opening therein, a plunger that slides back and forth in the opening as a bearing, stops in said opening at opposite ends of the plunger for limiting the reciprocating movement of the plunger to a predetermined stroke, the core, plunger and stops being made of magnetizable material, and an electromagnetic winding surrounding the opening near each end of the plunger, the improvement which comprises a shell around the outside of the core, plunger and stops, at least a portion of the shell comprising permanent magnets axially spaced from one another and carrying the flux in the shell including that produced by the excitation of the winding, a different one of the permanent magnets also surrounding the core at each end of the plunger.
2. The electromagnetic actuator described in claim 1 characterized by the electromagnetic winding being divided between two separate elcctromagnets, one at each end of the plunger, the permanent magnets also including one at each end of the plunger, and magnetic insulating material between the magnets at one end of the Plunger and those at the other end thereof.
3. The electromagnetic actuator described in claim 1 characterized by the core having confronting shoulders axially spaced from one another, the shell being held between the shoulders, one of the permanent magnets being located with one of its pole faces in contact with one of the shoulders, the other of the permanent magnets being located with its opposite pole face in contact with the other of said shoulders.
4. The electromagnetic actuator described in claim 2 characterized by each of the permanent magnets being of annular cross section and surrounding the outside of a different one of the electromagnets along most of the axial length of said permanent magnet and effectively spanning the locations at which there is a gap between the plunger and each end stop when the plunger is in contact with the other stop.
5; The electromagnetic actuator described in claim 1 characterized by the opening in the core having magnetic insulation in the side walls thereof at the locations where there are gaps between the plunger and each of the stops when the plunger is in contact with the stop at the other end of the stroke of the plunger.
6. The electromagnetic actuator described in claim 1 characterized by the stops being elements inserted into the opening in the core at opposite ends of said opening, and one of the elements having an opening therethrough of substantially smaller diameter than the plunger, and a shaft connected to the plunger and movable as a unit with the plunger, the shaft extending through the opening in the element that has the opening therein and being slidable in said element as a bearing.
7. The electromagnetic actuator described in claim 6 characterized by both of the stops having similar openings therein coaxial With the axis of the opening in the core, and shafts extending from both ends of the plunger through the openings in the stop for connection with apparatus that is to be operated by said actuator.
8. The electromagnetic actuator described in claim 1 characterized by the confronting faces of the plunger and stops being complementary and at least a pair of one of the faces having a projecting portion that fits into a recess in the confronting face to influence the force curve of the actuator.
9. The electromagnetic actuator described in claim 2 characterized by the permanent magnets and parts of the core being rings that fit around the other parts of the core and around the electromagnets and that stack on the core to form the shell of the actuator assembly.
References Cited UNITED STATES PATENTS 3,022,450 2/1962 Chase 335--229 XR 3,040,217 6/1962 Conrad 335234 3,139,565 6/1964 Levine 335-230 3,202,886 8/1965 Kramer 335234 3,381,181 4/1968 Weathers 335-230 XR GEORGE HARRIS, Primary Examiner US. Cl. X.R. 335-268 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Ltent No. 3,460,081 August 5, 1965 Alfred Tillman It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:
Column 4, line 51, "pair" shouid read part Signed and sealed this 21st day of April 1970.
1rd M. Fletcher, Jr.
WILLIAM E. SCHUYLER, JR sting Officer Commissioner of Patents
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3022450 *||Sep 15, 1958||Feb 20, 1962||Bendix Corp||Dual position latching solenoid|
|US3040217 *||Aug 10, 1959||Jun 19, 1962||Clary Corp||Electromagnetic actuator|
|US3139565 *||Oct 4, 1960||Jun 30, 1964||Edwards Company Inc||Electromagnetic bell striker actuating assembly|
|US3202886 *||Jan 11, 1962||Aug 24, 1965||Bulova Watch Co Inc||Bistable solenoid|
|US3381181 *||Jun 27, 1966||Apr 30, 1968||Sperry Rand Corp||Electromagnetic device|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3634735 *||Mar 30, 1970||Jan 11, 1972||Komatsu Mikio||Self-holding electromagnetically driven device|
|US3723926 *||Mar 22, 1972||Mar 27, 1973||Lucas Industries Ltd||Fluid pressure transducers|
|US3728654 *||Sep 20, 1971||Apr 17, 1973||Hosiden Electronics Co||Solenoid operated plunger device|
|US3814376 *||Aug 9, 1972||Jun 4, 1974||Parker Hannifin Corp||Solenoid operated valve with magnetic latch|
|US3878412 *||Sep 19, 1973||Apr 15, 1975||Kurpanek W H||Magneto-motive reciprocating device|
|US3882957 *||Jun 20, 1974||May 13, 1975||Sgl Ind Inc||Vehicle roll-over protection device|
|US3889219 *||Nov 1, 1973||Jun 10, 1975||Fluid Devices Ltd||Solenoid actuator with magnetic latching|
|US3894442 *||Apr 15, 1974||Jul 15, 1975||Ray Hembree||Semi-automatic electric gear shifting apparatus for a motorcycle|
|US3900822 *||Mar 12, 1974||Aug 19, 1975||Ledex Inc||Proportional solenoid|
|US4144514 *||Nov 3, 1976||Mar 13, 1979||General Electric Company||Linear motion, electromagnetic force motor|
|US4235153 *||Nov 2, 1978||Nov 25, 1980||General Electric Company||Linear motion, electromagnetic force motor|
|US4253493 *||Jun 16, 1978||Mar 3, 1981||English Francis G S||Actuators|
|US4533890 *||Dec 24, 1984||Aug 6, 1985||General Motors Corporation||Permanent magnet bistable solenoid actuator|
|US4539542 *||Dec 23, 1983||Sep 3, 1985||G. W. Lisk Company, Inc.||Solenoid construction and method for making the same|
|US4553732 *||Feb 13, 1984||Nov 19, 1985||Brundage Robert W||Solenoid controlled flow valve|
|US4560967 *||Apr 4, 1984||Dec 24, 1985||Parker-Hannifin Corporation||Force motor|
|US4751487 *||Mar 16, 1987||Jun 14, 1988||Deltrol Corp.||Double acting permanent magnet latching solenoid|
|US4873817 *||Aug 1, 1988||Oct 17, 1989||United Technologies Automotive, Inc.||Electrically controlled pressure relief valve system and method|
|US5149996 *||Feb 5, 1990||Sep 22, 1992||United Technologies Corporation||Magnetic gain adjustment for axially magnetized linear force motor with outwardly surfaced armature|
|US5300908 *||Oct 10, 1990||Apr 5, 1994||Brady Usa, Inc.||High speed solenoid|
|US6265956||Dec 22, 1999||Jul 24, 2001||Magnet-Schultz Of America, Inc.||Permanent magnet latching solenoid|
|US6424511 *||Jan 12, 2000||Jul 23, 2002||Purisys, Inc.||Automotive battery disconnect device|
|US6498416 *||Jun 19, 2000||Dec 24, 2002||Denso Corporation||Electromagnetic actuator permanent magnet|
|US7515024 *||Oct 26, 2006||Apr 7, 2009||General Protecht Group, Inc.||Movement mechanism for a ground fault circuit interrupter with automatic pressure balance compensation|
|US7581302 *||Jan 13, 2005||Sep 1, 2009||G. W. Lisk Company, Inc.||Solenoid valve combining a core and cartridge in a single piece|
|US8193885 *||Dec 7, 2006||Jun 5, 2012||Bei Sensors And Systems Company, Inc.||Linear voice coil actuator as a bi-directional electromagnetic spring|
|US8746280 *||Mar 17, 2010||Jun 10, 2014||Airbus Operations Gmbh||Controllable valve for an aircraft|
|US8928439 *||Jun 27, 2008||Jan 6, 2015||Robert Bosch Gmbh||Pole tube and actuation magnet having such a pole tube|
|US9004243 *||Aug 5, 2011||Apr 14, 2015||Beijing West Industries Co., Ltd.||Magneto-rheological damping assembly|
|US9046188 *||Dec 12, 2012||Jun 2, 2015||Techspace Aero S.A.||Solenoid actuator with magnetic sleeving|
|US9478339||Jan 27, 2015||Oct 25, 2016||American Axle & Manufacturing, Inc.||Magnetically latching two position actuator and a clutched device having a magnetically latching two position actuator|
|US9607746 *||Aug 28, 2013||Mar 28, 2017||Eto Magnetic Gmbh||Electromagnetic actuator device|
|US20060151733 *||Jan 13, 2005||Jul 13, 2006||G.W. Lisk Company, Inc.||Solenoid valve combining a core and cartridge in a single piece|
|US20070149024 *||Dec 7, 2006||Jun 28, 2007||Mikhail Godkin||Linear voice coil actuator as a bi-directional electromagnetic spring|
|US20070217100 *||Oct 26, 2006||Sep 20, 2007||General Protecht Group, Inc.||Movement mechanism for a ground fault circuit interrupter with automatic pressure balance compensation|
|US20090002109 *||Jun 27, 2008||Jan 1, 2009||Robert Bosch Gmbh||Pole tube and actuation magnet having such a pole tube|
|US20100252114 *||Mar 17, 2010||Oct 7, 2010||Lars Hoffmann||Controllable valve for an aircraft|
|US20130161546 *||Dec 12, 2012||Jun 27, 2013||Techspace Aero S.A.||Solenoid Actuator With Magnetic Sleeving|
|US20140062628 *||Aug 28, 2013||Mar 6, 2014||Eto Magnetic Gmbh||Electromagnetic actuator device|
|US20140076676 *||Aug 5, 2011||Mar 20, 2014||Thomas Wolfgang Nehl||Magneto-rheological damping assembly|
|USRE32644 *||Oct 3, 1986||Apr 12, 1988||Robert W. Brundage||Solenoid controlled flow valve|
|USRE32783 *||Jan 4, 1988||Nov 15, 1988||G. W. Lisk Company, Inc.||Solenoid construction and method for making the same|
|DE102009002215A1 *||Apr 6, 2009||Oct 21, 2010||Airbus Deutschland Gmbh||Controllable valve for hydraulic control of flame-resistant fluid within aircraft, has magnetic coil which moves component, provided in magnetic coil, from position to another position by short-term electric excitation|
|DE102009002215B4 *||Apr 6, 2009||Feb 13, 2014||Airbus Operations Gmbh||Steuerbares Ventil für ein Luftfahrzeug|
|EP0327894A1 *||Jan 26, 1989||Aug 16, 1989||Siemens Aktiengesellschaft||Magnetic control drive|
|EP1054200A3 *||May 13, 2000||Oct 24, 2001||SCHROTT, Harald||Bi-stable electromagnetic valve|
|EP1612812A1 *||Jun 20, 2005||Jan 4, 2006||Renault SAS||Direct drive linear actuator|
|EP2212602A1 *||Nov 10, 2008||Aug 4, 2010||Engineering Matters, Inc.||Flexible electromagnetic valve actuator modeling and performance|
|EP2212602A4 *||Nov 10, 2008||Nov 6, 2013||Engineering Matters Inc||Flexible electromagnetic valve actuator modeling and performance|
|WO2009062155A1||Nov 10, 2008||May 14, 2009||Engineering Matters, Inc.||Flexible electromagnetic valve actuator modeling and performance|
|U.S. Classification||335/234, 335/268|
|International Classification||H01F7/08, H01F7/122, H01F7/16|
|Cooperative Classification||H01F7/1615, H01F7/122|