AN ACTUATOR USING MAGNETIC FORCES TO REDUCE FRICTIONAL FORCES

DISPOSITIF DE COMMANDE FAISANT INTERVENIR DES FORCES MAGNETIQUES POUR REDUIRE LE FROTTEMENT

English Abstract

An actuator for opening and closing a valve with less resistance. The actuator
includes a rotor, a stator, a valve and a shaft. The shaft having a first and second end,
and an axis extending longitudinally therethrough. The stator, having an electromagnet
mounted thereon, and circumferentially mounted around the shaft that extends
therethrough. The rotor, fixedly mounted circumferentially around the first end, and having
a permanent magnet mounted adjacent to the electromagnet and spaced a first distance
therefrom. The valve including a rotary valve and valve seat. The rotary valve, mounted
circumferentially around and near the second end, having a valve opening therein. The
valve seat, mounted adjacent the rotary valve, having a seat valve opening therein, and
fixedly attached to the stator. There actuator is designed for axially moving the rotor from
the first distance to a second greater distance from the stator and thereby moving the
rotary valve further away from the valve seat, and then axially rotate the shaft to a second
position that aligned the seat valve opening and the valve opening, and then moving the
rotor from the second distance back to the first lesser distance.

French Abstract

Cette invention concerne un dispositif de commande de robinet à résistance réduite, comportant un rotor, un stator, un obturateur, un siège et une tige. Le stator, qui porte un électroaimant, est monté sur la tige. Le rotor, fixé par son centre à l'une des extrémités de la tige, comporte un aimant permanent faisant face à l'électroaimant, dont il est séparé par un espace. Le robinet est constitué d'un obturateur tournant présentant une ouverture et d'un siège présentant une ouverture correspondant à celle de l'obturateur. L'obturateur est fixé à la tige, près de l'extrémité opposée au stator. Le siège de l'obturateur, monté à proximité de ce dernier, est fixé au stator. Ce dispositif de commande est conçu pour déplacer le rotor axialement de manière à l'éloigner du stator, ce qui éloigne l'obturateur de son siège, à tourner la tige jusqu'à ce que l'ouverture de l'obturateur coïncide avec l'ouverture du siège, puis à déplacer de nouveau le rotor axialement de manière à le ramener à la même distance du stator qu'au départ.

Claims

What is claimed and desired to be secured by United States Patent is:
1. An actuator for opening and closing a valve, comprising;
a) a shaft having a first and second end, and an axis extending longitudinally
therethrough;
b) a stator, having an electromagnet mounted thereon, and circumferentially mounted
around the shaft that extends therethrough;
c) a rotor, fixedly mounted circumferentially around the first end, and having a permanent
magnet mounted adjacent to the electromagnet and spaced a first distance therefrom;
d) a rotary valve, mounted circumferentially around and near the second end, having a
valve opening therein;
e) a valve seat, mounted adjacent the rotary valve, having a seat valve opening therein,
and fixedly attached to the stator; and
f) means for axially moving the rotor from the first distance to a second greater distance
from the stator and thereby moving the rotary valve further away from the valve seat, and
then axially rotate the shaft to a second position that aligned the seat valve opening and
the valve opening, and then moving the rotor from the second distance back to the first
lesser distance.
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2. A valve device that opens and closes a valve opening, comprising:
a) a fixed valve seat;
b) a movable valve that is positioned and designed to move from a first position to a
second position that will open and close the valve opening;
c) an actuator, coupled to the movable valve, for moving the movable valve between the
open and closed positions by first forcing the movable valve away from the fixed valve,
moving the movable valve to either the open or closed position, and then forcing the
movable valve toward the fixed valve.
3. The valve device of claim 2, wherein the actuator is a rotary actuator and the movable
valve is a rotary movable valve.
4. The valve device of claim 3, wherein the actuator further comprising:
a) a shaft having a first and second end, and an axis extending longitudinally
therethrough;
b) a stator, having an electromagnet mounted thereon, and circumferentially mounted
around the shaft that extends therethrough;
c) a rotor, fixedly mounted circumferentially around the first end, and having a permanent
magnet mounted adjacent to the electromagnet and spaced a first distance therefrom;
d) a rotary valve, mounted circumferentially around and near the second end, having a
valve opening therein;
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e) a valve seat, mounted adjacent the rotary valve, having a seat valve opening therein,
and fixedly attached to the stator.
5. The valve device of claim 4, further comprising:
moving means for axially moving the rotor from the first distance to a second greater
distance from the stator and thereby moving the rotary valve further away from the valve
seat, and then axially rotate the shaft to a second position that aligned the seat valve
opening and the valve opening, and then moving the moving the rotor from the second
distance back to the first lesser distance.
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Description

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BACKGROUND OF THE INVENTIO~I
1. FIELD OF THE INVENTION
This inven~ion relates to actuators Particularly, there is an actuator tha~ uses
preset axial magnelic forces bolh to reduce ~he force needed lo open the valve by
5 eliminating some frictional forces, and to increase the force used in maintaining the
valve shut.
;!. DESCRIPTION OF THE RELATED ART
Various devices and methods of dealing with the complexities of rotary
10 actuators are legion. Examples of patents related to the present invention are as
follows, and each patent is herein incorporated by reference for the supporting teachings
U.S. pa~em no. 5,611,368 is a valve having magnetic force transmission
apparatus .
U.S. patent no. 5,484,133 is a manual override sys~em for linear magne~ically
operated valves.
U.S. pa~ent no. 5,372,351 is a manual override sys~em for rotary magnetically
operated ~Jalves
U.S. patem no. 5,356,112 is an electronically controlled valve having a totally
20 leakproof valve plug.
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U.S. patent no. S,234,292 is a ro~ational control device.
U . S . patent no . 5, 259,41 5 is a magnetic valve .
U.S. patent no. 5,226,627 is a m~gnetic valve.
U.S. patent no. 4,906,880 is an electromagnetic valve h~ving reduced
5 hysteresis.
U.S. pa~ent no, 4,647,010 is a çombined torque motor and rotary flow control
valve unit.
U.S. patent no. 4,496,134 is a rotary solenoid actuator.
U.S. patent no. 4,42~,5~8 is a proportional solenoid~
~0 U.S. pa~en~ no. 4,304,256 is a torque tr~nsmiKing assembly for rotary valve
members .
U.S. patent no.4,299,252 is a permanent magnet boosted elec~romagnetic
actuator .
U.S. patent no. 2,~i75,831 is a seatless valve.
The foregoing ~dt~;:l It::l reflect the state of the art of which the applicant is aware and
are tendered w~th the view toward discharging applicants' acknowledged duty of candcr
in disclosing inforrnation that may be pertinent in the examination of this application. It is
respecffully stir~ tetl, however, that none of these patents teach or render obvious, singly
or when considered in combination, applicant's claimed invention.
3. PROBLEM WI~H THE RELATED ~RT
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A common problem occurring during the ac~uation of actuators is that at~ached
valves are tightly fitted together, which oreates large frictional forces. Therefore, a need
exists to eliminate the frictional ~orces, created from having a tightly ~itted valve, that
opposes the movement of the valve.
SUMMARY OF THE INVENT10~
It is a feature of the invention to provide an actuator that uses prese~ axial
magne~ic forces both to reduce the force needed to open Ihe valve by eliminating10 some frictional forces, and to increase ~he force used in maintaining the valve shut.
A further feature of the illustrated embodimenl is to provide an ac~uator for
opening and closing a valYe with less resistance. The actua~or includes a rotor, a
staT~r, a valve and a shaft. The shaft having a first and ~econd end, and an axis
extending longitudinally Iherethrough. The stator, having an eleclromagnet mounted
5 thereon, and circumferentially mounted around the shaft that extends therethrough. The
rotor, fixedly mounted circumferentially around the first end, and having a perrnanent
magnet rnounted adjacent to the electromagnet and spaced a first distance therefrom. The
valve including a rotary valve and valve seat. The rotary valve, mounted circumferentially
around and near the second end, having a valve opening therein. The valve seat,
20 mounted adjacent the rotary vaive, having a seat valve opening therein, and fixedly
attached to the stator The actuator is designed for axially moving the rotor from the first
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distance to a sec~nd greater distance from the stator and thereby moving the rotary vzlve
fl~rther away from the valve seat, and then axially rotating the shaft to a secon~ position
that aligns the seat valve opening and the valve opening, and then movlng the rotor from
the second distance back to the first lesser distance.
The invenlion resides not in any one of Ihese fea~ures per se, but rather in thepar~icular combination of all of them herein disclosed and claimed. Those skilled in
the art will appreciate that the conception, I-pon ~hich this disclosure is based, rnay
readily be utilized as a basis for the designing of other structures, methods and
systems for carrying out the several purposes of the present invention. Further, ~he
abstract is neither intended to define the invention of the application, which is
rneasured by the claims, neither is it intended to be limi~ing as to the scope of the
invention in any way.
BRIEF DESCRIPTION OF T~E DRAWINGS
FIG. 1 is perspective exploded view of the preferred embodiment.
FIG. 2 is a cross seclion of one side of the preferred embodiment illustrating
the closed valve position.
FIG. 3 is a cross section of one side of the preferred embodiment illustrating
Ihe valve moving position.
FIG. 4 is a cross section of one side of ~he preferred embodiment illustrating
the open valve position.
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It is noted that the drawings o~ the inven~ion are not to scale The drawings aremerely schematic representations, not intended to portray specific parameter~ of the
invention. The drawings are intended to depict only typical embodiments of the invention,
and therefore should not be considered as limiting ~he scope of the invention. In the
drawings, like numbering represents like elements between the dra~ings.
DE~AILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention provides an actua~or that uses preset axial magnetic
forces bo~h to reduce ~he force needed to open the valve by eliminating some
friclional forces, and to increase the force used in rn~intaining the valve shut.
Regarding Fig. 1, there is a preferred embodiment actuator 10 (also referred to as a valve
device). In particular, actuator 10 includes a rotor 12, stator 14, shaft 16, and valve 18.
The rotor 12 includes a base pla~e 20, and permanent magnets 22. A thrust bearing 24,
separates the rotor 12 from the stator 14. The stator includes an armature core 26, a coil
28, ~nd base plate 30. Between the stator and the valve is a spacer 32, and a collar 34
~oth for spacing therebetween. The valve includes a rotary valve 36 with a rotary valve
opening 38, a valve seat 40 with a fLxed valve opening 4~. The armature core 26 and coil
28 form an electromagnet 31.
Referring to Fig. 24, there is illustrated the three key positions of operation for the
reduced friction actuator 10. Specifically, in Fig. 2, there is illustrated a closed valve
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position 50. Where the rotary valve opening 38 is not aligned with the fixed valve openlng
42
In Fig 3, there is illustrated a separated valve position 60. Where the rotary valve
36 is spaced from the valve seat 40 by air gap 62.
In Fig. 4, there is illustrated an open valve posltion 70. Where the rotor 12 has the
two valve openings 38 and 42 aligned and the rotary v~lve 36 is again closely positioned
next to the v~lve se~t.
In operation of the preferred embodiment, the valve is first in a closed position 50.
Where the rotary valve opening 38 is not aligned with the fixed valve opening 42 and the
rotary valve 36 is tightly fit adjacent to the valve seat 40 as a result of the permanent
magnet 22 attracting the non-energized armature core 26. In Fig. 3, the rotary valve 36
has been separated from the valve seat 40 as ~ result of sending a current through coil 28,
which causes the armature core 26 to become a magnet having the same polarity as the
adjacent permanent magnet 22, in th~ instant illustration both have ~ south "S" polarity.
In Fig 4, the open valve position 70 i~ created when the rotor 12 has rotated as a result
of the repulsive and attractive magnetic forces between the permanent magnets 22 and
oppositely polarized armature cores 26. Uniquely, as the rotor approaches the optimum
magnetica11y attractive ~ositiun the axial displacement ~vill decrease to a point that allows
the rotary valve 36 to tightly flt ~ cPnt the valve seat 40
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Rem~rks About the Preferred Embodiment
One of ordinary skill in the ar~ of designing and using actuator controlled valves will
realize many advantages frorn stu~ying and using the preferred embodiment. For
5 exampie, since the rotary valve 36 separates from the valve seat 40 before rotating to an
open position there is an elimination of the prior art frictional forces that opposed the
rotation of the rotary valve 36. A skilled artisan will realize that the shaft is so mounted to
allow axial displacement to allow for the up and down motion of the rotor and ~ttache~
valve Also, an artisan knows that the axial motion of the valve 36 will be directed along
10 the main axis of the shaft 16
It is easily understood that spacers ~2 determine the spacing between permanent
magnets 22 and armature cores 26, and that the resultant magnetic forces therebe~Neen
can be adjusted by changing the length of spacers 32. As a res~lt, thë length of spacers
32 will have a direct impact on the amount of pressure rotary valve 36 exerts on valve seat
40 in both the open and closed positions Furthermore, cc~llar 34 and spacers 32 are used
to maintain a proper spacing between stator 14 and valve 18 during ~he axial motion of the
rotary valve 36.
Of particular note, the preferred embodiment has a three step process for opening
and closing the valve 18. The first separates the two valve parts, the second rotates the
20 rotary valve, the third forces the t~,vo valves parts together again. This sequence occurs
during b~th the opening and closing of the valve 18.
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Variations of the Preferred Ernbodirnent
Although the illustrated ernbodiments discuss the arrangement of the actuator 10
5 using only ~NO armature cores 26, it is contemplated to use any number of armature cores
wherein each adjacent core is oppositely polarized when the coils are energized
Additionally, it is eq~ally contemplated to use the concept of the preferred embodiment in
a linear actuator. Where the moving valve portion 36 will be disengaged from the fixed
position val~re portion 40 when the repulsive forces are created between the rotor 12 and
0 stator 14. The preferred embodiment illustrates the starting position of the valve to be
closed However, it is contemplated to have the valve star~ in the open position and move
to the closed position
The present embodiment shows the l~se of spacers 32 and collars 34 to maintain
both the proper spacing between the stator and valve and the rotor and stator during any
5 resulting axial motion. However, there are many ~ays to provide this needed displacement
during operation. ~or example7 one end of the shaft could be coupled in a retaining cavity
that allows for a~cial displ~cP~il,ent, or the base plate 30 could be molded with an extension
that allowed for needed axial motion but limited the axial displacernent of the rotary valve
36, like a tab extending downward therefrom. Therefore, any known device that limits the
20 axial but allows for rotational movement would work.
The current ei,lbo~li,nent shows a valve o~er,i".J on the rotary valYe, however there
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are many ways to create an open and closed position. For example, the rotary valve 36
could be a thick spoke, like on a bike tire, that is positioned over the seat v~lve opening
42 to close the valve 18, and moved thereof when opening the valve 18 Therefore, any
known valve device would work.
While the invention has been taught with specific reference to these embodiments,
someone skilled in the art will recognize tha~ changes can ~e made in form and detail
without departing from the spirit and the scope of the invention. The described
embodiments are to be considered in all respects only as illustrative and not restrictive.
The scope of the invention is, there~ore, indicated by the ~ppended claims rather than by
the description All ohanges that come within the meanlng and range of equivalency of the
claims are to be embraced within their scope.
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Representative Drawing