Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
l:LS~Z29 360-78-1140
_ACKGROUND
_IELD OF_ THE INVENTION
This invention relates to electromagnetic solenoid valves
and actuators having rapid response time and extended
stroke. More particularly, the invention relates to such
devices having a single electromagnet and a telescoping
armature.
PRIO~ ART
Solenoid actuators are known in the art. These actu-
ators often comprise a moveable armature maintained in a
spaced relationship from an electromagnet. The distance
therebetween, called an air gap, thereby defines the stroke
of the armature. It is desirable to obtain a fast acting
actuator having a long stroke. However, increasing the
stroke implies a larger air gap which further implies de-
veloping a greater magnetic field to produce the requisite
force to attract the moveable armature. One method of de-
veloping these larger forces is to increase the size of themagnetic circuit requiring a larger stator, coil and arma-
ture as well as requiring larger excitation currents. How-
ever, these larger units often take a greater time to build
up or energize and deenergize the required magnetic field.
Similarly, the response time of the armature is slowed be-
cause of its increased mass or inertia. It should be noted
that it is not possible to fully compensate for these
longer response times merely by increasing the level of
exciting current and that the increased currents may only
produce excessive local heating and power usage.
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SUMMARY OY T 1~ E T NVENT I ON
The present inventiorl includes an electromagnetic
solenoid responsive to electric actuation commands. The
solenoid may be used as an actuating device to move an
associated member into or away from a housing or as a ported
valve to controllably open and close a passage therein
permitting fluid to flow therethrough.
The invention relates to an apparatus responsive to
electrical command signals comprising: a housing including
a first passage extending therethrough, magnetic means,
disposed within the housing for developing a magnetic field
in response to the electric commands input thereto; telescoping
armature means including a plurality of members disposed
within the housing between the magnetic means and the first
passage for moving each of the members toward the magnetic
means in a telescoping manner in response to the magnetic
field, piston means operatively connected to the telescoping
armature means extending through the first passage for
reciprocally rnoving within the first passage in response to
the motion of the telescoping armature means; biasing means
connected to the telescoping armature means for biasing the
telescoping armature, absent electric command signals, ln a
spaced relationship relative to the magnetic means7 and wherein
the housing further includes a second passage opposite the
first passage and where the magnetic means includes a third
passage in alignment with the second passage, second piston
means movably situated within the second and the third
passages and operatively connected to at least one member of
the plurality of members of the telescoping armature means
.
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for reciproc,llly movillg relative t:o the secolld and third
passages in response to the movement of the telescoping
armature means.
In another aspect, the lnvention relates to a valve
responsive to electrical command signals comprising: a
housing including a first passage extending therethrough and
a fluid port adapted to receive fluid in communication
therewith; magnetic means, disposed within the housing Eor
developing a magnetic field in response to the electric
commands input thereto; telescoping armature means including
a plurality of members disposed within the housing between
the magnetic means and the first passage for moving each of
the members toward the magnetic means in a telescoping manner
in response to the magnetic field, the telescoping armature
means comprising: a substantially rectangular first member
that is responsive to the magnetic field, receiving means
responsive to the magnetic field for receiving and for moving
the first member, the receiving means including a rectangular
member having a U-shaped cross-section, the rectangular member
having a rear wall having a hole therein and two opposingly
situated sidewalls, the rear wall and the side walls forming
a receiving cavity therebetween; piston means slidably received
through the rear wall and operatlvely connected to the first
member and extending through the first passage for reciprocally
moving within the first passage in response to the motion of
the first member and for opening and closing the fluid first
passage to permit fluid flow therethrough; biasing means
connected to the piston means for biasing the first member
absent electric command signals into the receiving means in a
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spaced Lela~;onsllip re~ativc lo ~he magllctic mcans.
Thus, the solenoid comprises a multi-piece armature
moveably situated, within a housing, with respect to an
elect:romagnet The preferred embodiment employs a laminated
E-type electromagnet or stator and an armature having
substantially rectangular pole pieces which conform to the
substantially rectangular E-type electromagnet. Other
electromagnets such as a cylindrical electromagnet and armature
configurations may be substituted. The multi-piece armature
comprises inner and rear pole pieces maintained in a spaced
relationship apart and biased from the electromagnet. The
inner and rear pole pieces in their deactivated mode are
telescopically received one into the other and are sized to
define a bi-level air gap relative to the electromagnet.
Activation of the solenoid produces a non-uniform magnetic
force which attracts both pole pieces to the electromagnet.
The bi-level air gap of the preferred embodiment is one in
which one pole piece is initially maintained at a smaller air
gap than the other pole piece. This relationship permits
large electromagnetic forces to be exerted upon the closer
pole piece. This large force is sufficient to move both
polè pieces towards the electromagnet thereby similarly
reducing the air gap related to the farther spaced pole pieae~
As the armature approaches the electromagnet the force exerted
upon the initially farther pole piece increases dramatically
to a level sufficient to continue to pull the farther pole
piece to the electromagnet. The telescopic relationship
permits the farther situated pole piece to overtravel relative
to the closer po]e piece once the closer pole piece has been
pulled to the electromagnet.
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It is preferable to prevent the armature members from
contacting the stator or electromagnet. If this contact
should occur, the magnetic properties of the stator and
armature laminates may diminish, the uniformity of the air
gap may change and the deactivation response time might
increase because of the magnetic hystersis developed. The
proper minimum spacing can be achieved in a number of ways
such as using a non-magnetic spacer or an auxiliary stop
which engages a portion of the armature prior to the con-
tact with the stator. To develop useable motion one of thepole pieces is connected to a shaft or piston, which can be
an integral part of the armature; the motion of this shaft
or piston can move an associated member of a coacting de-
vice or control the opening and closing of an associated
valve, vent or passageway.
The preferred embodiments of the present invention
illustrate a solenoid designed to pull the piston or asso-
ciated apparatus towards the solenoid housing. An alter-
nate embodiment illustrates the use of the present inven-
tion in a solenoid designed to push the piston or asso-
ciated apparatus away from the housing. A further embodi-
ment replaces the E-type electromagnet with a C-type elec-
tromagnet.
An advantage of the present invention is that the
25 multi-piece armature permits extended stroke, i.e., piston
movement, while not requiring electromagnets having exces-
sively large cores or coils or using excessive exciting
currents.
Another advantage is rapid piston response resulting
from the reduced armature mass and increased actuating
force.
It is an object of the present invention to provide a
solenoid having rapid response and extended stroke. Many
other objects and advantages of the invention will be clear
from the detailed description of the drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure l: is a sectional view of the present
invention.
Figure 2: is an end view.
Figure 3: is another sectional view through Section
3-3 o Figure 1.
Figure 4: illustrates an exploded view of the
armature shown in Figures l and 3 and is found on the second
sheet of drawings.
Figure 5: illustrates a graph of the electromagnetic
force as a function of air gap.
Figure 6: is a sectional view illustrating an
alternate embodiment of the present invention and is found on
the second sheet of drawings.
Figure 7: is another sectional view through Section
7-7 of Figure 6 and is found on the second sheet of drawings.
Figure 8: is a further modification of the present
invention~
Figure 9: is a sectional view through Section 9-9 of
Figure 8.
Figure 10: is a sectional view of an alternate
embodiment of the invention.
Figure 11: is an exploded view of a portlon o~ the
armature shown in Figure 10.
Figure 12: illustrates still another embodiment of
the present invention.
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1~5~2~9 360-78-1140
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is now made to Figures 1, 2 and 3 which
illustrate views of the preferred embodiment of the present
invention. There is shown an electromagnetic solenoid
actuator 20 having a housing 30 adapted to enclose a mag-
netic means such as a stator or electromagnet 60 and tele-
scoping armature 70. (The term stator and electromagnet
are used interchangeably.) A resilient means such as a
helical spring 100 interposes a section of the housing 30
to bias a shaft or piston 84 therebetween.
The housing 30 comprises a base portion 32, adapted
to mate with an armature receiving portion 34 and a re-
tainer portion 36 adapted to mate with the armature receiv-
ing portion 34.
In the embodiment shown in Figures 1, 2 and 3 the
base portions 32 and armature receiving portion 34 are
cup-like structures designed to interfit forming a chamber
38 therebetween to support and to enclose the stator 60 and
the armature 70. The armature receiving portion 34 con-
tains a base 40 and tubular portion 42 extending therefrom.
More particularly, the tubular portion 42 contains two
concentric bores such as the centrally located bore 44 and
the second larger bore 45. The intersection of the bore 44
with bore 45 forms a support means such as a shoulder 46 for
receiving and for supporting the helical spring 100. The
tubular portion 42 is further adapted to interfit portion
36. Portion 36 functions to secure the armature 70 within
the bore 45 while permitting the sliding engagement of the
piston or shaft portion of armature 70. As shown, portions
32 and 34 and 36 can threadably engage one another by
utilizing pairs of coacting screw threads 48a and 48b.
Alternatively, snap-fittings or the press-fit engagement of
the respective housing portions can be substituted for the
screw threads 48a and 48b.
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In the preferred embodiment of the invention, the
e!lectromagnetic stator 60 is an E-type electromagnet having
poles 62a, b, c, and adapted to securely fit within the
base portion 32 of the housing 30 and further adapted to
receive electrical commands input thereto through an elec-
trical connector such as connector 64.
The electromagnet 60 is preferably constructed using
a laminated core fabricated from one of the known varieties
of high silicon oriented magnetic steels. The electro-
magnet 60 also includes at least one coil of wire 66 woundabout a suitably sized bobbin 68 which is fitted to the
center leg or pole 62b of the E-type electromagnet. While
the preferred embodiment requires an E-type electromagnet,
other shapes may be substituted. The ~-shape naturally
follows from the fact that the high silicon oriented mag-
netic laminates are often available as flat stock.
The armature 70 comprises a plurality of inter-
connected and nested pieces. While the preferred embodi-
ment utilizes a two piece armature 70, the present inven-
tion is amenable to other armature configurations includingthe multi-piece armatures shown in Figures 10, 11 and 12.
The embodiment of the armature 70 shown in Figures 1 and 3
includes an inner member such as a plate-like inner pole
piece 72 having a laminated poleface 74 and a rod-like mem-
25 ber 76 protruding therefrom. The inner member is tele-
scopically received within a receiving member such as the
rear pole piece 78 which has laminated polefaces 79. This
relationship is further illustrated in Figure 4 which is an
exploded diagram of the armature 70. The receiving member
30 of the preferred embodiment is substantially rectangular to
conform with the dimensions of the inner member and E-type
electromagnet and partially envelopes the inner member.
The partial envelopment is achieved by utilizing a rear
pole piece 78 having a U-shaped cross-section. The inner
35 and receiving members of the preferred embodiment are sized
so that when both members are nested, i.e., telescopically
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received one into the other, poleface 74 and poleface 79
are parallel to one another but do not lie in the same
plane. The significance of this uneven poleface position-
ing will be discussed later.
Reference is again made to Figures 1 and 3 which fur-
ther illustrate the relationship of the armature 70 to the
other components of the solenoid 20. The solenoid 20 is
shown in a partially activated mode, i.e., wherein the
electromagnet 60 has moved the armature ~0, more
particularly, the rear pole piece 78 into engagement with
the spacer 69. The fully deactivated mode is where the
armature 70 is biased by the spring 100 into the armature
receiving portion 34 as illustrated by the phantom lines.
The armature 70 further includes a spring retainer such as
the washer 83 and piston 84 having a shoulder 86. The
piston 84 is sized to slidably engage the interior of bore
45. The valve plate 96 further includes a centrally
located hole 98 sized to permit passage of a portion of the
piston 84. As illustrated in Figure 1 or 3, the piston 84
is hollow and secured to the rod 76 by a threaded member 88.
It is apparent that the member 88 can be a retaining screw,
or the movable member of a coacting apparatus so activated
such as a three-way valve or the spool of a spool valve of a
fuel injector for automotive engines. A valve seat such as
spacer or washer 90 interposes piston 84 and member 88 to
ensure proper seating with the valve plate 96. Alterna-
tively, the piston 84 can be directly secured to the rod 76
using the threaded engagement as shown in Figure 4. In
addition, that portion of piston 84 extendinq through the
valve plate 96 in Figure 4 can be modified to similarly
threadably engage a valve or coacting apparatus.
The retainer portion 36 comprises another cup-like
structure having a base 92 with passage 94 located therein.
The retainer portion 36, as previously mentioned, thread-
ably engages portion 34 securing the valve plate 96 there-
between.
1~5~Z2~ 360-78-1140
It should be apparent from Figures 1 and 3 that in
the solenoid's deactivated state, the spring 100 will bias
the inner and rear pole pieces 72 and 78 respectively at
positions of maximum travel with respect to the legs 62 of
the electromagnet 60 therein establishing a bi-level air
gap therebetween. As an example, the face of pole piece 72
may be maintained at an air gap T which is greater than the
respective rear pole piece air gap of T/2.
It is apparent from Figure 5 that as the air gap
increases, the available electromagnetic attractive force
(F) significantly and rapidly decreases so that at dis-
tances in excess of 0.04 inches the force available for
actuation (of the armature 70) is small. Consequently, if
the stroke of the solenoid is to be large (i.e., 0.04
inches) it would have been required as in prior art sole-
noids to increase the exciting current, which increases
power requirements or to enlarge the dimensions of the
electromagnet 60 or armature pole pieces (72, 78) thereby
increasing actuator size and weight which further reduces
20 the solenoid response time. The present invention obviates
these problems as can be seen from the following discus-
sion.
As previously described, the solenoid 20 in its de-
activated or unenergized state will permit the spring 100
25 to bias the armature 70 at an extreme position relative to
the stator or eIectromagnet 60 therein defining a bi-level
air gap.
A controller (not shown) will, upon demand, energize
the coil 66 with a predetermined current producing a deter-
30 minable electromagnetic force between the stator 60 andboth armature pole pieces (72 and 78), respectively. As an
example, assume the inner pole face 74 is disposed within
the housing 30 in the de-energized state at a distance T
from the stator 60 and further assume the rear pole piece
35 78 (which partially envelopes the inner pole piece 72) is
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clisposed so that its pole face 79 is at a distance T2,
wherein T2 = T/2, from the stator 60. Upon energizing the
c:oil 66, a magnetic force Fl will be exerted on the farther
situated inner pole piece 72. In addition, a substantially
larger magnetic force of attraction F2 will be exerted upon
the closer or rear pole piece 78. The magnitude of the
force F2 can be obtained from Figure 5 and is sized to be
sufficiently large to cause the entire armature 70 to move
towards the stator 60. As the rear pole piece 78 moves
towards the stator 60, it engages and carries with it the
inner pole piece 72 thereby moving the piston 84 and the
associated valve or apparatus from their respectively
biased positions closer to the housing.
The rear pole piece 78 will continue to move to the
electromagnet 60 until it contacts the spacer 69. It is
believed that the spacer 69 can be totally or partially
eliminated from the invention. The spacer 69 is one method
of controlling the minimum air gap between electromagnet 60
and armature 70.
As the inner pole piece 72 is moved toward the stator
60 by the movement of rear pole piece 78, its respective
air gap is similarly reduced. Consequently, by virtue of
this smaller spacing, the magnetic force acting upon the
inner pole piece 72 will sufficiently increase to a level
which will permit the inner pole piece 72 to overcome the
spring bias force and continue to move to the electromagnet
60 (or spacer 69) after the rear pole piece 78 has stopped.
Therefore, the motion of the piston 84 and associated parts
in response to an actuation command is a multi-step process
comprising a first segment wherein the piston 84 is moved
by the rear pole piece 78 and a second segment
characterized by increased magnetic forces acting upon the
inner pole piece 72 permitting forces acting upon the inner
pole piece 72 permitting the inner pole piece 72 and piston
84 to overtravel relative to the rear pole piece 78 and to
continue to move into the electromagnet 60.
360-78-1140
Other methods of halting the motion of the inner pole piece
~ould include incorporating mechanical stops (not shown) to
limit the armature travel or sizing the armature 70 so that
the valve seat 90 engages the valve plate 96 prior to the
5 time that inner pole piece 72 engages the electromagnet 60
as shown in Figures 8 and 9.
In this manner, an extended stroke solenoid 20 is
achieved by positioning the telescoping armature 70 rela-
tive to the electromagnet 60 to produce an unequal or non-
linear force therebetween. In addition, it should be noted
that the bi-level (or multi-level) air gaps of the tele-
scoping armature 70 provides a means for electromagnetic
force multiplication. This can be seen from the following
example:
If both pole pieces (72 and 78) were situated at the
extreme air gap (T), the resultant force acting upon
the armature 70, assuming equal pole piece facial
areas, would be 2Fl. However, utilizing the
multi-level air gap, the resultant forces acting upon
the armature (Fl + F2) is larger than the previously
discussed resultant force for the same exciting cur-
rent.
Reference is made to Figures 6 and 7 which illustrate
an alternate embodiment of the present invention; more par-
25 ticularly, an alternate configuration of an armature having
two telescoping pole pieces. The alternate solenoid 200
contains a multi-portion housing 210 having a base portion
212 and armature receiving portion 214 enclosing an
electromagnet 220, armature 230 and valve 240. As
30 previously described in the prior embodiment, a spring 250
biases the armature against the armature receiving portion
214 of the housing 210. The armature 230 comprises, as
before, an inner member including an inner pole piece 232
and a receiving member including a rear pole piece 234.
35 However, in this alternate embodiment, the inner pole piece
232 is disposed closer to the electromagnet 220 is than the
360-78-1140
11
rear pole piece 234. The inner pole piece 232 is tele-
scopically received within the rear pole piece 234, how-
ever, in this embodiment the piston 236 and valve 240 are
attached to the rear pole piece 234. It may be desireable
to insert a second spring such as the helical spring 238
having a low spring constant between the inner pole piece
232 and rear pole piece 234 to maintain the desired separa-
tion during deactivated periods.
The dynamics of armature movement are similar to that
previously described and will not be described in detail.
However, in this embodiment it is the front pole piece 232
which is attracted to the electromagnet 220 and initially
pulls the rear pole piece 234 toward the electromagnet 220.
As the inner pole piece 232 approaches the electromagnet
220, the magnetic forces acting upon the rear pole piece
234 increase to a level permitting the rear pole piece ~34
to overtravel relative to the inner pole piece 232 permit-
ting the extended stroke.
Figure 6 illustrates a further modification of the
solenoid 200 wherein the housing 210 is provided with a
port 260 adapted to receive an external pressure, vacuum or
fluid (not shown). In addition, the port 260 contains a
passage 262 which extends into the housing 210. The exter-
nal pressure, vacuum or fluid is selectively communicated
to bore 270 in correspondence to the opening and closing of
valve 240.
Inspection of the previously described embodiments
illustrate that the solenoids are designed to draw the
slide or piston or associated apparatus towards the housing
upon activation and permit the slide, piston, etc., to re-
assume its pre-activation position by moving outward when
the electric actuation commands are removed.
Figures 8 and 9 illustrate modifications to the pre-
ferred embodiment which will enable the solenoid 300 to
extend member 310 upon activation. A comparison of Figures
8 and 9 with Figures 1 and 3 reveals the nature of these
360-78-1140
12
modifications. One modification is that threaded member 88
(which may be the cooperating part of an associated ap-
paratus) has been replaced by cap screw 312 or threaded
plate. The center leg 62 of the E-type electromagnet is
5 provided with a passage 302 and the base portion 32 of the
housing 30 is further provided with an opening or passage
304 which is coaxial to the passage 302.
A second slide or piston 310, slidably disposed in
passages 302 and 304, is shown connected to the inner mem-
10 ber, i.e., the front pole piece 72. It is preferable toalign the piston 310, and passages (302,304) to an axis 312
which is colinear to the center of the rod 76 and bores 44
and 45. The slide or piston 310 may be an integral part of
the inner pole piece 72, however, it is preferable to fab-
15 ricate the slide or piston 310 from a non-ferromagnetic
material which is connected to the inner pole piece 72. It
is not necessary for the entire inner or rear pole pieces
(72 and 78) be fabricated from ferromagnetic materials.
Non-ferromagnetic material such as aluminum or plastic may
20 be substituted for the majority of the bulk of the pole
pieces with ferromagnetic, preferably laminated, inserts
comprising the polefaces 74 and 79. Furthermore, since a
portion of the center leg 62b in Figures 6 and 7 is removed
to accommodate the passage 302, design considerations may
25 require a compensatory enlargement of the center leg 62b.
Reference is now made to Figures 10-12 which
illustrate further embodiments of the present invention.
Figures 10 and 11 illustrate a solenoid 400 incorporating
an E-type electromagnet 402 and an armature 410 having a
30 rear pole piece 412 fabricated from a plurality of nested
laminated members 414a-d and an identical set of nested
members 416a-d. Each of these members 414 and 416 are
respectively received one into the other and define a non-
linear air gap (T, 3/4T, 1/2T, 1/4T) with respect to the
35 electromagnet 402. Each member contains a centrally
~ 29 360-78-1140
13
located coaxial passage 420 sized to receive a portion of
the inner member 422, more particularly, pin 424. The
inner member comprises a pair of pins 424 (only one is
shown in Figure 11) each of which is received within a
holder 426 and an armature shaft or piston 430 which con-
tains a spring reaction shoulder 432. The armature shaft
430 threadably receives valve 434. The armature 410 is
contained within the solenoid 400 by housing 432.
Figure 12 illustrates solenoid 450 showing another
armature 452 having a plurality of nested members 454 a-d.
In addition, solenoid 450 illustrates a C-type electro-
magnet having laminates 456 having at least one coil if
wire 458 wound about bobbin 460.
It is apparent that other electromagnets may be sub-
stituted for the E-type electromagnet. In addition, the
design can be modified to accommodate other than rectan-
gular pole pieces, which were chosen to conform with
rectangular electromagnets. Consequently, changes and
modifications in the above-described embodiments can, of
course, be carried out without departing from the scope
thereof. Accordingly, that scope is intended to be limited
only by the scope of the appended claims.
