US2998552A - Solenoid construction used in fuel valves - Google Patents

Description

Aug. 29, 1961 w. A. RAY 2,998,552 souawoxn CONSTRUCTION USED IN FUEL VALVES Filed July 8, 1957 2 Sheets-Sheet 1 J Z G. 2.

W 4 ,4 HE/EIIJ TOR. 6, /4 /LL/ M 4 Aug. 29, 1961 w. A. RAY 2,998,552

SOLENOID CONSTRUCTION USED IN FUEL VALVES Filed July 8, 1957 2 Sheets-Sheet 2 i L g 15'45 0 420 V 65 #28 225 PIZ'G. 6. 227 a Z0 Q4254 IZIT I I. Us /a [ZLL/ 7/ 77] 29 INVENTOR. VV/LL/AM 4 64/ BY Mw Unite The present invention relates generally to solenoid constructions and, more specifically, to solenoid operated valves for controlling the supply of fuel to heating apparatus.

An object of the present invention is to provide an improved solenoid construction used in fuel control valves which results in substantial freedom from hum when the solenoid is energized with alternating current.

Another object of the present invention is to provide an improved solenoid construction which is relatively simple, inexpensive and in which the movable armature does not stick to the associated magnetic structure when the solenoid is de-energized.

These objects are achieved mainly by providing a flexible diaphragm which is attached to the armature or plunger to guide and maintain one end of the plunger with respect to the associated magnetic structure, the diaphragm being flexible with respect to the direction of movement of the plunger by being substantially rigid with respect to forces which may be applied thereto transversely to the direction of movement of the plunger.

The associated magnetic structure for the plunger is also considered novel in conjunction with the diaphragm in that, while an extended core member is provided near one end of the solenoid Winding, the other end of the solenoid into which the plunger extends does not include a magnetic core skirt as is present in conventional constructions, with the result that in the instant construction a different flux pattern exists at the end of the solenoid into which the plunger extends. This construction allows the use of a straight bore for the plunger.

Another main feature of this construction is that a substantial portion of the flux enters the lower diaphragm plate or end plunger plate in a substantially vertical direction, thus contributing to the elimination of hum which is otherwise produced by lateral or sidewise move .ment of the plunger.

Another object of the present invention is to provide an improved magnetic structure for a solenoid that contributes to a minimizing of hum but yet increases the magnetic pulling forces developed on the plunger.

Another object of the present invention is to provide a solenoid construction of this character in which a restoring spring continuously exerts a biasing force on the plunger in all positions of the plunger, i.e., throughout the full stroke of the plunger.

Another object of the present invention is to provide a short stroke, quiet type, stick-free, low cost solenoid.

The damages resulting from sticking solenoids can indeed be serious, particularly when a solenoid is used in controlling flow of fuel to a clothes drier and, for this reason, oftentimes clothes driers are provided with two sets of solenoids and dual temperature controls to avoid damages resulting from sticking of one of the solenoids. Such sticking solenoid results mainly from dirt or viscous material being baked on the plunger or on the outer wall of the plunger guide tube to the extent that the plunger is prevented from closing upon interruption of solenoid energizing current.

In the instant construction the possibilities of sticking are greatly minimized in that the arrangement of elements is such that it allows a comparatively large clearance space between the plunger and its surrounding tube which,

n m n is "4 states ateiit wince 2,998,552 Patented Aug. 29, 1961 2 in this instance, does not serve as a guide, the guiding being accomplished by a flexible diaphragm, as characterized above, attached to the plunger.

Another object of the present invention is therefore to provide an improved solenoid construction for obtaining the above advantages with a construction that allows the use of the relatively large clearance space between the plunger and its surrounding tube on which substantial amounts of dirt and viscous material may be baked without restraining movement of the plunger either to its energized position or, in particular, to its de-energized position.

Another object of the present invention is to provide a construction or" this character in which the diaphragm is permeable and serves not only as a plunger centering element but also as a filtering element to keep dirt from the fluid line out of the plunger chamber while yet allowing passage of clean fluid in and out of the plunger chamber.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a top plan view of the structure shown in FIGURE 2 taken substantially in the direction indicated by the lines 1-1 in FIGURE 2.

FIGURE 2 is a sectional view taken substantially on the lines 22 of FIGURE 1.

FEGURE 3 is a sectional view taken substantially on the lines 3& of FIGURE 2.

FIGURES 4, 5, 6 and 7 are sectional views corresponding to FIGURE 2, but through three different modifications, each of which also embodies features of the present invention.

FIGURE 8 is a plan view of a flat type spring which is used in the constructions illustrated in FIGURES 5, 6 and 7.

In each one of the four constructions shown herein, the numeral 11 indicates a valve casing having a passage therethrough which is divided by an angled partition 12 to form an inlet chamber 13 and an outlet chamber 14, the horizontal portion of the partition having a circular port 15 around the inlet end of which is a raised annular valve seat 16.

A movable valve element comprising a resilient disc 17 cooperates with the raised seat 16 to close the valve when the associated solenoid is de-energized. The valve 1.7, in FIGURE 2, is centrally mounted at the lower end of plunger or armature 18 together with a diaphragm 19 and a washer-shaped element 20 of magnetizable material; the diaphragm 19 is retained sandwiched between the valve disc 17 and washer-shaped element by fastening means such as a rivet 21 which is fastened centrally in the plunger 18 and has portions thereof engaging the retaining washer 22 whereby the elements 17, 19 and 2t; are retained between an annular shoulder 13A of the plunger and the retaining washer The outer periphery of the diaphragm 19, which has generally a rectangular pattern, is clamped between the rectangular flange portion 23A of the inverted cupshaped member 23 of magnetizable material and a generally rectangular gasket 24; and four fastening screws 2s (FEGURE 1) pass through the corners of the element 23A and are threaded in the valve casing 11 to secure the element 23 to the casing 11 to compress the coil spring 27 in all positions of the plunger 18. The coil 27 is a spiral spring having one of its ends engaging the annular corner of element 23 and the other one of its ends bearing against the washer-shaped element 20. By this expedient the valve disc 17 is pressed into engagement with its seat 16 due to the combined efiorts of the flexible diaphragm 19 and the spring 27. The valve disc 17 is raised from its seat against the biasing force exerted by the diaphragm l9 and spring 27 upon energizing the solenoid winding 23.

The winding 28 is wound on a circular nonmagnetizable spool 29 and is retained in place by the following construction.

One end of the spool 29 rests on the plate portion 233 of the element 23. The plate portion 233 is centrally apertured portion is chamiered or countersunk at 23C to provide a seat for the outwardly flared end of the tube 33 which is of nonmagnetizable material. It will be observed that the tubular member 31? has a lower portion of relatively large diameter adjacent the plunger 18 to provide a large annular clearance space between the plunger and the tube at that region; and such tubular member 30 has an upper integrally formed portion of relatively small diameter within which is snugly fitted a stationary core member 32. The upper end of the tubular member 30 has an inturned end which cooperates with a shoulder on the core member 32 and to which is welded by weld 33 the spool retaining member 34 which is of magnetizable material.

It is noted that the member 34 is generally annular and has two cylindrical portions 34A and 34B of different lengths joined by an annular plate-like portion 34C. The cylindrical portion 34A extends downwardly between the spool 29 and the tubular member 3t? and terminates above the lower end of the core member 32, while the other cylindrical portion 348 encircles and contacts the member 23 on a circle.

It is thus observed that there is an annular air gap which extends between the lower end of the cylindrical portion 34A and the plate portion 233, so that the magnetic flux path between these two elements is substantially vertical without a substantial horizontal component that is in a direction to produce sidewise movement of the plunger 18 when the coil 28 is energized,

e., the possibilities of so-called sidewise hum occasioned by lateral movement of the plunger is minimized.

To aid in maintaining the magnetizable member 34 in place, a conventional spring type deformable washer 35 has its resilient projections engaging the core member extension 32A and its peripheral portion engaging the member 34.

The member 34 is provided with an apertured portion 341) through which the leads for the coil 23 extend.

As shown in FIGURE 2, the core member 32 is provided with a centrally disposed recessed portion into which is press-fitted a copper ring 36 that serves as a shading coil; and such core 32 has a central projecting portion 323 which may be slightly tapered to snugly fit within a cooperating centrally disposed seat 13B formed in the upper end of the plunger insert 18C of a magnetizable material. A copper ring 13D serving as a shading coil is snugly fitted within the insert 18C and the outer wall of the plunger portion liiE, which is of course also of magnetizable material. A centering pin 3? is secured in the core member 32 and extends centrally through a portion of relatively large diameter in the insert 18C and also into the aligned central apertured portion 18F of the plunger when the coil 28 is energized, for centering purposes. While in certain instances the provision of the centering pin 37 is desirable, the same may be omitted as in the arrangements shown in FiGURE-S and 6.

Centering and guiding of the plunger 13 is accomplished essentially by the diaphragm 19 which has a large degree of flexibility in a direction corresponding to the longitudinal axis of the plunger but which is substantially rigid with respect to forces applied transversely to such longitudinal direction, occasioned particularly by magnetic forces developed that tend to move the plunger transversely in a vibratory condition. In other words, the diaphragm w prevents sidewise movement of the plunger 18 and, hence, greatly minimizes vibration of the plunger and resulting hum.

A main feature of this construction is the conversion of a large portion of the bottom flux flowing into the plunger structure in a vertical direction instead of radially to eliminate side hum.

Another feature of the diaphragm plate 2G is that in. the conversion of the lower flux to vertical flux, instead or" radial flux, the pull of the solenoid is increased.

If desired, a thin layer of nonmagnetic material is coated or plated either on the projection 3213 or on the seat 13B to assure separation of these two elements when the coil 28 is de-energized.

In general, this construction involving bottom plate 2% permits the use of a relatively small coil, measured axially, without the use of a relatively thick lower plate 233 notwithstanding that a relatively large clearance is provided between the plunger and tube 30. Without the bottom plate 212*, the lower plate 238 would have to be thickened in order to get the required flux across this relatively large gap. To explain this another way, the high clearance which is provided would normally require more area in the lower plate 2313 for flux to flow into the plunger. However, by use of the diaphragm washer 29 which is relatively inexpensive and controlled as to thickness and flux carrying capabilities, a relatively large flux carrying area is provided thereby permitting the use of a wide air gap between the washer 20 and lower plate 23B and also between the plunger and lower plate 233.

The arrangement illustrated in FIGURE 4 is essentially the same as in FIGURE 2 but differs in the following respects.

In the arrangement shown in FIGURE 4 the top magnetizable member 134 (corresponding to 34 in FIGURE 2) has its inner cylindrical portion 134A terminating closer to the lower end of the core member 32 and the large cylindrical portion corresponding to cylindrical portion 3413 in FIGURE 2 is omitted. An additional difference is that the plunger insert 18C bottoms against a copper ring 38 to assure a nonmagnetic gap between the insert 18C and the body portion of the plunger except for the small peripheral contact area between the insert 18C and the plunger body portion 18E. Additionally, core portion 32A has a tapped hole therein for receiving the fastening screw 39 which serves to retain the cover 40.

The arrangement shown in FIGURE 5 is essentially the same as FIGURE 2, but in this case the core member 232 (corresponding to core member 32) extends a greater distance through the center of the coil so that the distance between the lower end of the core member 232 and the lower end of the cylindrical portion 34A is greater. Additionally, the centering pin (centering pin 37 in FIGURE 2) is omitted in FIGURE 5; and the insert (insert 18C in FIGURE 2) is omitted.

It is noted also that the lower magnetizable member 223 is provided with an enlarged downturned portion 223A instead of being chamfered as at 23C in FIGURE 2. Further, instead of providing a spiral type of spring such as the spring 27 in FIGURE 2, the arrangement shown in FIGURE 5 includes a flat type spring 227 of the character shown in FIGURE 8 to supplement the biasing force exerted by the diaphragm 19.

in FIGURE 6 the core member 332 extends still a further distance with respect to the coil 28 and indeed occupies the entire space between and slightly beyond the ends of the coil form or spool 29. The upper magnet lable member in this instance comprises simply a ring 334 having its inner peripheral edge in engagement with the core 332 and which is retained by the deformale conventional washer 335. The lower magnetizable member 323 has its circular edge in contact with the core 332. A copper ring or shading coil 336 is centrally disposed and recessed within the core 332 having the bulbous projection 332B which is adapted to seat in a hemispherical indented portion 41A of a magnetizable plate 41. Such plate 41 preferably has a thin nonmagnetic plating or coating 42 to assure return of the valve closure member 17 to its closed position when the coil 28 is de-energized. A flat type spring 227 of the charac ter shown in FIGURE 8 produces a constant force which supplements the biasing force produced by diaphragm 19.

If desired, the diaphragm 19, in each of the arrangements shown herein, may have small apertures therethrough so that the pressure on opposite sides of the diaphragm is equalized as illustrated by the apertured portion 19A in FIGURE 2. In other words, the diaphragm is permeable to serve as a filtering element to keep dirt from the fluid line out of the plunger chamber while yet allowing clean fluid to flow in and out of the plunger chamber.

The arrangement shown in FIGURE 7 includes a ring shaped dirt filter screen 309 which is retained in the inlet fluid passageway by a retaining ring 301. The plunger 302 is secured to the diaphragm washer 303 of magnetizable or permeable material which, in turn, is secured to the diaphragm 304 which is sandwiched between the lower plate 305 of magnetizable material and the valve body 3%. The diaphragm has an annular thickened portion 303A which cooperates with the raised valve seat 306A on the valve body 306. The coil 369 is retained between the bottom plate 305 and top plate 310. The flared tube 311 of nonmagnetizable material has its lower end secured to the lower plate 305 and its upper end secured to the tube head 312 of magnetizable material which is counterbored to snugly receive the tube head button 315 of magnetizable material and the copper shading ring 316 and shading washer 317, the ring 316 and washer 317 being spaced from each other. The top plate 310 is secured to the tube head 312. The cover 318 is retained by screw 319. A conical centering recess 302A in the upper end of plunger 302 is engageable with the rounded stationary button 315.

In each of the arrangements there is provided a coil and an armature loosely mounted with respect thereto together with diaphragm means associated with the armature that serves as a guide to center the armature when the coil is energized, the diaphragm means being substantially yieldable only in a direction longitudinal of the armature so as to prevent transverse movement of the armature when the coil is energized but yet providing a biasing force on the armature for moving the armature from its attracted position after the coil is de-energized. Further, in each one of the arrangements, it is observed that there is a means acting on a central portion of the armature for engaging and centering the same in the attracted position of such armature, such means comprising, in each instance, a shading coil together with a projecting portion that enters and engages a central reentrant portion of the armature.

While each of the arrangements shown herein includes a spring that exerts a biasing force in such direction as to return the armature to its nonenergized position, such considered to influence the guiding and centering action of the diaphragm means since such diaphragm means is considered to be the sole means whereby the armature is guided in its movement; and such diaphragm means in the attracted position of the armature cooperates with that portion of the core structure that engages the armature and the shading coil so as to substantially eliminate hum.

While the arrangement is described for energization with alternating current, the same may be energized with direct current and is particularly useful in reducing or eliminating hum when the source of DC. comprises rectified half-Wave pulses derived from an AC. source.

' The spring shown in the various embodiments serves solely as a means for assuring quick return of the armature to its de-energized position and in that limited respect supplements one of the functions of the diaphragm means; and while it presently appears that the provision of such a spring is preferred for this limited purpose, the same is not considered essential in achieving a hum-free solenoid.

It will be observed that in each one of the embodiments a plate of magnetizable or paramagnetic material in the form of a washer is secured centrally to the diaphragm so as to be movable therewith and so as to provide a flux path for flux and such washer in the embodiments shown in FIGURES 2, 4, 5 and 7 serves to introduce such flux in the lower end of the plunger or armature attached to such washer and the diaphragm so that such flux extends generally longitudinally through substantially the full length of the plunger. This flux thus entering the plunger through the washer supplements the flux which enters the plunger through the lower plate 2313 in FIGURES 2 and 4, the lower plate 223 in FIGURE 5, and the lower plate 305 in FIGURE 7. By thus providing the magnetizable washer on the diaphragm, the air gap or clearance between such lower plate and the plunger is relatively large and the arrangement does not require a thickened lower plate for reasons previously mentioned. Thus in FIGURES 2, 4, 5 and 7, the flux enters the plunger at two ditterent spaced regions on the plunger.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. A hum free solenoid construction including a coil, a core member mounted within said coil, an armature within and attracted by said coil and core member, a flexible diaphragm having a central portion thereof attached to said armature in all positions of said armature and having an outer portion stationarily mounted with respect to said coil, said diaphragm being flexible with respect to axial movement towards said core member and being substantially rigid with respect to movement in a direction transverse to said axial movement, said diaphragm serving as a sole means for guiding movement of said armature towards said core member, a magnetizable plate centrally mounted on said diaphragm and in axial alignment with said armature and contacting said armature, a pair of magnetizable members mounted on adjacent ends of the coil and separated by an air gap when said coil is energized, one of said members being also separated from said plate by an air gap.

2. A hum free solenoid including a coil, a core member mounted in said coil, a movable armature, a flexible diaphragm having an outer portion stationarily mounted with respect to said coil, a magnetizable plate mounted on said diaphragm and centrally with respect to said core member, said diaphragm being attached to said armature in all positions thereof and being flexible with respect to axial movement of said armature towards said core member and being substantially ri id with respect to movement in a direction transverse to said axial movement, said diaphragm serving as a sole means for guiding movement of said magnetizable plate towards said core member, a pair of magnetizable members mounted on opposite sides of said coil and separated by an air gap when said coil is energized, one of said members being separated from said plate by an air gap.

3. A hum free solenoid construction including a coil, a core member mounted within said coil, an armature attracted by said coil and core member, a flexible diaphragm having a central portion thereof attached to said armature in all positions of said armature and having an outer portion stationarily mounted with respect to said coil, a magnetizable plate carried by said diaphragm in engagement with said armature, said diaphragm being flexible with respect to axial movement of said armature towards said core member and being substantially rigid with respect to movement in a direction transverse to said axial movement, said diaphragm serving as the sole means for guiding movement of said armature towards said core member, a second magnetizable plate surrounding said armature and serving to conduct flux to an intermediate portion of said armature.

4. A hum free solenoid construction incuding coil, an armature movable in said coil, a stationary core in said coil, a diaphragm having its outer ends fixed with respect to said coil, a magnetizable plate carried by said diaphragm, said armature being secured to said diaphragm in all positions of said armature and said plate with the plate and armature contacting, and a magnetizable structure surrounding said coil, said structure including said core and a member which is spaced from said core to define a first air gap and which is spaced from said plate to define a second air gap.

5. A hum free solenoid construction including, a coil, a core member extending into one end of the coil and closing the same, an armature extending into the other end of the coil, a diaphragm supporting said armature 8 in all positions of said armature, a magnetizable member on said diaphragm, a magnetizable member disposed adjacent said other end of said coil and terminating near the inner diameter of said coil so as to define a flux path with said core which extends in a direction generally parallel to movement of said armature, said magnetizable member serving also to produce flux for attracting the magnetizable member on said diaphragm.

References Cited in the file of this patent UNITED STATES PATENTS 2,181,423 Gille Nov. 28, 1939 2,358,828 Ray Sept. 26, 1944 2,612,188 Persons Sept. 30, 1952 2,650,617 Wasser Apr. 1, 1953 2,651,744 Acklin Sept. 8, 1953 2,661,022 Latour Dec. 1, 1953 2,735,047 Garner Feb. 19, 1956 2,856,569 Birge Oct. 14, 1958 2,858,487 Imrnel Oct. 28, 1958 FOREIGN PATENTS 9,496 Great Britain Apr. 19, 1910 651,479 France Oct. 9, 1928 692,963 France Aug. 11, 1930

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