CA1123036A - Electric spool for dry axial solenoid - Google Patents
Electric spool for dry axial solenoidInfo
- Publication number
- CA1123036A CA1123036A CA309,248A CA309248A CA1123036A CA 1123036 A CA1123036 A CA 1123036A CA 309248 A CA309248 A CA 309248A CA 1123036 A CA1123036 A CA 1123036A
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- base
- pole
- coil
- magnetic
- 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
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Classifications
-
- 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
- H01F7/1607—Armatures entering the winding
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Electromagnets (AREA)
- Magnetically Actuated Valves (AREA)
Abstract
Electric Spool for Dry Axial Solenoid Abstract of the Disclosure An electric spool assembly for a dry axial solenoid includes a magnetic pole and a sleeve formed of non-magnetic tube material and a magnetic base. The pole has a portion which is received in axial interfitting relation with one end of the sleeve. The base has a portion received in interfitting relation with the opposite end of the sleeve thus forming a first telescopic joint between the sleeve and the pole at one end of the sleeve and a second telescopic joint between the sleeve and the base at the other end of the sleeve. The sleeve defines an axial air gap between the pole and the base forming an opening. Means are provided on the outer surface of the assembly forming an annular coil-receiving space defined at least in part by the outer surface of the sleeve. An electric coil having turns of wire wound in tension around the sleeve outer surface causes the sleeve to be physically compressed in the regions where the sleeve is telescopically interfitted with the base and the pole thereby thermally and mechanically connecting the sleeve with the hub and the base. A highly efficient thermal and magnetic connection is thus formed between the base, the pole and the sleeve and the close proximity of the turns of the electric coil to these parts not only enhances the magnetic efficiency but also enhances the thermal efficiency of the unit.
Description
~.23~
ELECTRIC SPOOL FOR DRY AXIAL SOLENOID
Background of the Invention ;
The invention relates to a dry plunger solenoid or to such a solenoid formed with a dry armature cavity. It enjoys certain of the advantages of the wet plunger solenoid construction of applicant's U. S. patent No. 4,04~,324 issued August 23, 1977. In that U. S. patent, a movable wet plunger type solenoid is particularly adapted to operate hydraulic valves and the like in which the plunger cavity is Eormed by an integral joining of a magnetic base and a magnetic pole with a non-ferrous sleeve, and in which the parts are retained in assembled relation without welds or threaded joints by reason of the compressive effect of the electric winding.
The cavity is formed by a spool assembly in which ,; the turns of the coil are applied directly to the spool assembly. The directly placed windings not only enhance the heat sink capability of the unit, but also compress the non-ferrous sleeve against the pole and the base by reason of the accumulative compression created from the tension on the wire during winding.
Summar~ of the Invention The advantageous features of constructions of the '- wet plunger solenoid, as described above, may be applied to,. ~
the construction o~ a dry plunger solenoid.
A three piece spool assembly includes a magnetic base, a magnetic hub, and an interfitting non-magnetic or `~ non-ferrous sleeve in which portions of the sleeve overlie . ,.
portions of the base and the pole and form a close fit ~., , . .
,,.:
~ ., , , J`
:
Docket 6487 therewith, and in which the spool parts are retained in assembled relation by the cumulative compressive force of the coil wound onto the sleeve.
The non-ferrous sleeve may consist of a section of low cost tubing material cut accurately to length to define the spacing between the pole and the base. A highly efficient thermal and magnetic connection is thus formed be~ween the base, the pole and the sleeve, and the close pro~imity of the turns of the electric coil to these parts - 10 not only enhances the magnetic efficiency, but also enhances the thermal efficiency of the unit.
These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims.
Brief Description of the Drawings ; Fig. 1 is a side view of a wet plunger solenoid;
Fig. 2 is an enlarged longitudinal section through the solenoid taken generally along the line 2-2 of Fig. 3;
Fig. 3 is a transverse section taken generally along the line 3-3 of Fig. 2;
; Fig. 4 is a longitudinal section similar to Fig. 2.,,,~
of a dry solenoid according to this invention; and Fig. 5 is a transverse section taken generally along the line 5-5 of Fig. 4.
Description of Figs. 1-3 Figs. 1-3 illustrate the wet plunger embodiments as described and claimed in applican~'s U. S. patent No 4,044,324 issued August 23, 1977. The solenoid is housed in a generall~ cylindrical open-ended case 10 of magnetic ' ~
' ' ~ 3~
Docket 6487 material, formed with an annular front flange 11 at the open end thereof. The flange 11 is adapted for mounting onto a valve or the like which is to be controlled by the solenoid. The case 10 includes a coil or spool assembly S indicated generally at 12, which in assembly, is inserted within the open end of the case 10~
The spool assembly 12 is made up of three pieces including a base 14, a pole 15 and a sleeve 16. The base 14 as well as the pole 15 are similarly formed of ferrous or other magnetic material. The base 14 is formed with an axially extending cylindrical portion 14a and a rearwardly extending portion 14b, the latter extending through a rear opening 13 formed in the case 10. The base 14 is further formed with an annular, radially extending shoulder 14c ~7hich defines one radial wall of a coil-receiving cavity.
The inside surface of the cylindrical portion 14a forms an .
,` axial portion of an armature cavity 17~
`~ The pole 15 is spaced physically and magnetically from the base 14 and includes a cylindrical pole portion 15a, having an inside diameter which similarly forms an axial portion of ~- the armature cavity 17 and of the same diameter as the inside -~ diameter of the base portion 14a. ~urther, the pole 15 is provided with an annular, radially extending shoulder 15b, the inside surface of which forms the opposite wall of the ' 25 coil-receiving cavity.
~ he sleeve 16 is formed of non-magnetic material such as aluminum or brass, and is fitted in telescopic relation as 'v, ''''''''' ~
.f~;3~
Docket6487 a press fit over the outside surface of the base portion 14 and into abutment with the shoulder 14c.
Similarlyt the cylindrical pole portion 15a of the pole 15 is fitted in telescopi.c relation to the sleeve 16 as S a close press fit.
The xemote end of the sleeve 16 is in abutment with the adjacent wall of the shoulder portion 15b. Preferably, the fit between the sleeve and the base is also a close press fit. If desired, a suitable sealant may be applied to the .10 interface between these parts.
The sleeve 16 is formed with a cylindrical portion 16a axially lntermediate the base and the hub, bridging the space therebetween, and formed with an inside diameter essen-tially the same as that of the base and hub, thus forming an intermediate wall portion of the armature cavity 17.
A solenoid armature 20 formed of magnetic materialis received within the cavity 17 of the spool assembly 12 for ` axial movement therein into coaction with the pole 15. A non-magnetic shaft 22 extends axially ~rom one end of ~he armature 20 by which the mo~ement of the armature 20 is transrnitted to the exterior of the solenoid. ~ommonly, the shaft 22 will be connectea to operate the spool of a hydraulic valve or the like.
The interior armature cavity is closed by an end cap 2S 25, the outer diameter of which is received within the case opening. The end cap 25 is provided with a central clearance opening 26 through which the shaft 22 extends while per~itting , hydraulic fluid under pressure to enter into the interiGr of `~ the solenoid cavity. The armature 20 is held and guided in 3~ spaced relation from the cylindrical cavi~y walls by means of ,~
Dock~t 6487 .~
a plurality o longitudinally extending bearing strips 28, preferably four in number at 90 intervals, and pressed into longitudinal recesses formed within the armature. The upper sur~aces of the strips 28 proj~ct a few one-thousands of an inch or less abov,e the surface of the armature 20 and provide for the guidance of the armature within the cavity while assuring close magnetic coupling between the armature, the base ~nd the pole. Longitudinal openings or passageways 30 are formed in underlying relation to the strips 28 and extend axially between the ends of the axmature 20 to prevent hydraulic lock-up of the armature by permitting the flow of fluid there-through from one end of the armature to the other as the ax,mature moves axially within the solenoid.
The end cap 25 is statically sealed at the base 15 by an O-ring 32 on the inside face of the cap. An axial cylindrical portion 25a forms one wall of the interior cavity ~, and defines an abutment for the armature 20, and is thus posi-'' ~ioned radially within the pole portion 15a. An annular face ,",; seal 34 may be provided on the outside surface of the end cap ' 25 by means o~ which the end cap is sealed to a valve housing -~ 20 or the like.
~, It is common to provide external means by which the , armature 2~ may be moved for the purpose of operating the ;; connected valve, and for this purpose a non~magnetic manual ; actuator 35 is received within the base extension 14b. The actuator is provided with an enlarged head 36 in the cavity 17 '~ forming in effect an opposite axial abutment for the armature 20. The actuator 35 extends ou-twardly of the case 10, and ....
support a snap ring 38. A compression spring ~0 is positioned ,~, between the riny 38 and the outex exposed surface of the base 1 .
~8 3~:i Docket 6487 . .o urge ~he actuator into its normally retracted position, as shown. The stem of the actuator is sealed to the base by means of an O-ring 42. An elastomeric boot 44 may be fitted to the remote end of the base portion 14b to cover the other-wise exposed end of the actuator 35.
In order to effectuate a high pressure coil sub-assembly lZ and to join and seal the sleeve 16 to the base 14 and the pole 15 in the regions where these parts are telescoped, the turns of an electric coil 50 axe wound directly on the .; 10 outer cylindrical surface of the sleeve 16. Preferably, a layer 52 of insulating tape is first applied to the outer ~ surface and.the turns o the electric coil are then wound ; directly onto the sleeve between the shoulder portions l~c and 15b, preferably while applying substantial tension to the ~..
15 wire during wincling. Insulating washers 54 isolate the coil 50 from the shoulders 14c and 15b. The amount of tension employed . can vary in accordance with the size of the wire employed and the strength of the wire. The accumulative effect of winding ~: the turns of the coil 50 onto the sleeve 16 results in com-~ 20 pression of ~he sleeve 16 about the ~elescopic portions of the -:.. pole 15 and the hub 14, assuring a fluid-tight joint therebe-tween, and at the same time, assisting materially in resisting ... thP deflection of the spool assembly by reason of the applica-tion of fluid under pressure into ~le interlor of the solenoid.
. 25 The elimination o-f the conventional coi.l form enhances .~. the heat sink capacity of the solenoid. Thus, the turns of the coil 50 are in substantially closer heat transmitting relation to the sleeve 16 than would be the case where a coil form were ~ used. Preferably, the sleeve 16 i.s made of a non-magnetic metal .. ~ 30 having a good heat conductivit~, such as brass, to transmit the heat from the coil 50 to the adjacent structure of the : .
~, G
Docket 6487 .
solenoid. Th~ arrangement is one in which a spool asse~bly is formed free of threaded joints by using economical slip fits. The sleeve 16 is actually in compression and firmly engages the interfitted base and pole. An assembly is formed which maintains its integrity up to 8000 psi or more, permit-; ting continuous operation in the range of 3000 psi or more.
The cylindrical portion 15a of the pole 15 may beformed with any suitable configuration, such as the tapered form shown, to provide a desired linearity in operation. The 0 tapered form shown has particular use as a proportional act-~ uator, and is a preferred embodiment. It is preferred to form ; the end cap 25 of magnetic material to provide specific force curves or operating characteristics, in which case a non-magnetic spacer 60 keeps the armature 20 rom completely closing the gap with the cap and becoming magnetically held.
; However, the cap 25 may also be made of non-magnetic material ; and the spacer 60 omitted. The solenoid may also be operated ~ as a two-position unit, although the employment of the tapered ~ c pole section 15a permits the solenoid to be used as a propor-tional actuator.
The solenoid is free of any sliding or moving seals which imnede the movement of the armature 20. The seals 32 and 34 are static and thus not subject to wear. The one moving seal 42 on the stem of the manual actuator 25 is . . .
infrequenfly used, does not impede the movement of the armature, and is not subject to appreciable wear.
By example only and without limitation, suitable - ~ solenoids in accordance with this invention have employed coils wound as follows:
' . i ~ 3 Docket 6487 (A) 615 turns, No. 22 AWG conductor wound with 15 ounces of tension to provide a 12 volt DC unit, with 2.88 ohms resistance and 36 watts, one-quarter duty.
~ B) 1,204 turns, No. 25 AWG conductor wo~md with 15 ounces of tension to provide a 12 volt DC unit, with 1l.39 ohms resistance and 9 watts, continuous duty.
(C) 1,204 turns, No. Z5 AWG conductor wound with 15 ounces of tension to provide a 24 volt DC unit, with 11.39 ohms resistance and 36 watts, one-quarter duty.
~D) 2,420 turns, No. 28 AWG conductor wound with 12 ounces of tension to provide a 24 volt DC unit, wi~h 45.86 ohms : ` :
; resistance and 9 watts, continuous duty.
(E) 4,718 turns, No. 31 AWG conductor wound with 8 ounces of tension to provide a 110 volt ~C unit, rectified to a 100 volt DC, with 179 ohms resistance and 36 watts, one-quarter duty.
(F) 8,873 turns, No. 34 AWG conductor wound with 4 ounces of tension to provide a llO volt AC unit, rectified to a 100 volt DC unit, with 613 ohms resistance and 9 watts, continuous duty.
The specific strength in psi attributed to the coil 50 on the sleeve 16 may be represented by the formula:
PSI = 2 TS x S. F.; where T = radial wall thickness of coil in inches, S ~ yield strength of wire in pounds per square inch, I. D. = inside diameter of coil 50 in inches, and ; S. F. = space factor of wir~.
Appl~-in~ this formula to the above examples tA) ~ provides the following theoretical burst strength increases in pSi by ' .' -~
Or~
Docket 6487 ;~
reason of the coil 50 on the sleeve 16. (In each calcuation T = .265", S = ]0,000 psi, I.D. = .845" and S. F. were as indicated.) ` (A) 4,272 psi with 22 AWG wire, S. F. = .6811 (B) 4,186 psi with 25 AWG wire, S. F. = .6675 (C) 4,186 psi with 25 AWG wire, S. F. = .6675 (D) 4,191 psi with 28 AWG wire, S. F. = .6683 (E) 4,084 psi with 31 AWG wire, S. F. = .6511 (F) 3,829 psi with 34 AWG wire, S. F. = .6105 It will be noted that while tension, per se, is not a . ~
~; theoretical factor in calculating the burst strength :
provided of a coil, nevertheless the presence of tension is considered to be important since it results in the initial ` compression of the sleeve 16 and thus prestresses the sleeve ,. . .
about the interfitted base and pole regions, and the initial actual deflection of the spool assembly 12 within the operating range of the solenoid will be appreciably less than if the coil 50 were wound with minimum tension.
, . . .
Further, the compression effect advantageously forms a fluid-tight seal between these interfitting parts. In manufacture, it has been found that the I.D. of cavity 17 `- will be somewhat decreased after the coil 50 is wound, at which time it may be suitably rebored or honed precisely to the desired dimension before the solenoid is finally assembled.
Description of Figs. 4-5 The elmination of the conventional coil form - provides a solenoid construction which advantageously may be used with a dry plunger as described in connection with the _9_ `, ~
;36 Docket 6487 present invention. This is particularly true in the construction of a proportional solenoid in which an axial portion of a cylindrical pole is selectively saturated by the movement of an armature in telescopic relation to the pole~ The attachment of the base and the hub as an integral part of the assembly by means of this invention, that is by means of the sleeve and the winding of the turns of the coil thereon, provides an economical and efficient structure having superior heat dissipating characteristics.
The case 110 is formed of magnetic material and has a front flange 111 at the open end of the case. The flange 111 may be as shown in Fig. 3 in connection with the flange 11, or alternatively, it may be provided with external threads for mounting the solenoid, as a cartridge-type r" 15 solenoid.
The coil or spool assembly 112 of the invention is made up essentially of three separate pieces, n~mely, the base 114, the hub or pole 115, and a tubular spacer or ; sleeve 1160 The base and pole are formed of ferrous material and have generally the same configuration as that described in Figs. 1-3. The non-magentic conne~tion sleeve however, may be formed of a length of tubing material which has been accurately cut to a desired length The sleeve thus defines the spaced-apart distance, and accordingly defines a working air gap 116b in the axial space between the hub and the pole. ~ow cost aluminum or brass tubing or the like may be employed for this purpose, which forms a slip fit over the respective cylindrical sections 114a and 115a of the adjacent magnetic parts. The end cap 125 need ~10-' ~
.. .
~4.~ 3 Docket 6~87 not be sealed in a fluid tight manner, although conventional seals may be employed where dust, fluids, or other ;~contaminations are anticipated. The end cap 125 may be a simple press fit into the open end of the case 110, and as ~`5 previously mentioned, may be Eormed of either magnetic or non-magnetic material in accordance with the desired `~'rcharacteristics of the solenoid.
iThe armature 120 is somewhat modified from the armature 2a previously described in that the axial passageways therethrough may also be eliminated.
Additionally, it has been found advantageous to support the armature 120 at its inner end, on a sleeve bearing 128. The bearing 128 has an inner surface mounted on the armature 120 and has an outer surface forming a close running fit with the inside diameter of the cylindrical portion 114a of the base 114. The bearing 128 may be formed of sintered porous bearing metal, such as bronze, and in appropriate cases, impregnated with a desired lubricant. A second sleeve bearing 129, preferably ~ormed of the same material as that 20 of the bearing 128, is supported in the end cap portion 125a and slidably guides the shaft 122, so that the armature 120 is guided at one end by the bearing 128 and is guided at its remote end by the bearing 129 in association with the shaft.
The turns of the electric coil 150 are wound in direct engagement with the ou~er surface of the sleeve 116, and a layer 152 of insulating tape, shown in somewhat exaggerated thickness, in Fig. 4, is preferably applied before winding to provide electrical isolation for the coil 150. The coil 150 is wound in tension into the annular ' ~
"
'~
~.23~6 Docket 6487 space defined by the radial shoulders of the hub and base, and the interfitting outer cylindrical surface of the ~; sleeve, causing the sleeve 116 to be compressed about the interfitted cylindrical sections therein. In this manner, an excellent thermal bond and mechanical connection is formed between the sleeve 116 on the one hand and the interfitted base and pole portions on the other hand.
The movable plunger 35 of Fig. 2 has been omitted.
In its place, a non-magnetic button 135 is inserted with a head 136 received within the armature cavity and positioned .
to come into abutment wlth the armature 120 ln the retracted ` position of the armature, as shown in Fig. ~. The button 135 prevents the armature 120 from coming into direct ~ contact with the base 114.
; 15 It is further understood that the shaft 122 may be extended through the armature 120, or a suitable connection ~, made thereto through an aperture in the a~ial end 114b of the base 114 to provide an electrical feedback signal. One such electrical feedback signal arrangement is shown in the U. S. patent of Myers, No. 3,870,931 issued March 11, 1975, and assigned to the same assignee as this invention.
While the form of apparatus herein described ; constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.
- What is claimed is:
' "~
ELECTRIC SPOOL FOR DRY AXIAL SOLENOID
Background of the Invention ;
The invention relates to a dry plunger solenoid or to such a solenoid formed with a dry armature cavity. It enjoys certain of the advantages of the wet plunger solenoid construction of applicant's U. S. patent No. 4,04~,324 issued August 23, 1977. In that U. S. patent, a movable wet plunger type solenoid is particularly adapted to operate hydraulic valves and the like in which the plunger cavity is Eormed by an integral joining of a magnetic base and a magnetic pole with a non-ferrous sleeve, and in which the parts are retained in assembled relation without welds or threaded joints by reason of the compressive effect of the electric winding.
The cavity is formed by a spool assembly in which ,; the turns of the coil are applied directly to the spool assembly. The directly placed windings not only enhance the heat sink capability of the unit, but also compress the non-ferrous sleeve against the pole and the base by reason of the accumulative compression created from the tension on the wire during winding.
Summar~ of the Invention The advantageous features of constructions of the '- wet plunger solenoid, as described above, may be applied to,. ~
the construction o~ a dry plunger solenoid.
A three piece spool assembly includes a magnetic base, a magnetic hub, and an interfitting non-magnetic or `~ non-ferrous sleeve in which portions of the sleeve overlie . ,.
portions of the base and the pole and form a close fit ~., , . .
,,.:
~ ., , , J`
:
Docket 6487 therewith, and in which the spool parts are retained in assembled relation by the cumulative compressive force of the coil wound onto the sleeve.
The non-ferrous sleeve may consist of a section of low cost tubing material cut accurately to length to define the spacing between the pole and the base. A highly efficient thermal and magnetic connection is thus formed be~ween the base, the pole and the sleeve, and the close pro~imity of the turns of the electric coil to these parts - 10 not only enhances the magnetic efficiency, but also enhances the thermal efficiency of the unit.
These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims.
Brief Description of the Drawings ; Fig. 1 is a side view of a wet plunger solenoid;
Fig. 2 is an enlarged longitudinal section through the solenoid taken generally along the line 2-2 of Fig. 3;
Fig. 3 is a transverse section taken generally along the line 3-3 of Fig. 2;
; Fig. 4 is a longitudinal section similar to Fig. 2.,,,~
of a dry solenoid according to this invention; and Fig. 5 is a transverse section taken generally along the line 5-5 of Fig. 4.
Description of Figs. 1-3 Figs. 1-3 illustrate the wet plunger embodiments as described and claimed in applican~'s U. S. patent No 4,044,324 issued August 23, 1977. The solenoid is housed in a generall~ cylindrical open-ended case 10 of magnetic ' ~
' ' ~ 3~
Docket 6487 material, formed with an annular front flange 11 at the open end thereof. The flange 11 is adapted for mounting onto a valve or the like which is to be controlled by the solenoid. The case 10 includes a coil or spool assembly S indicated generally at 12, which in assembly, is inserted within the open end of the case 10~
The spool assembly 12 is made up of three pieces including a base 14, a pole 15 and a sleeve 16. The base 14 as well as the pole 15 are similarly formed of ferrous or other magnetic material. The base 14 is formed with an axially extending cylindrical portion 14a and a rearwardly extending portion 14b, the latter extending through a rear opening 13 formed in the case 10. The base 14 is further formed with an annular, radially extending shoulder 14c ~7hich defines one radial wall of a coil-receiving cavity.
The inside surface of the cylindrical portion 14a forms an .
,` axial portion of an armature cavity 17~
`~ The pole 15 is spaced physically and magnetically from the base 14 and includes a cylindrical pole portion 15a, having an inside diameter which similarly forms an axial portion of ~- the armature cavity 17 and of the same diameter as the inside -~ diameter of the base portion 14a. ~urther, the pole 15 is provided with an annular, radially extending shoulder 15b, the inside surface of which forms the opposite wall of the ' 25 coil-receiving cavity.
~ he sleeve 16 is formed of non-magnetic material such as aluminum or brass, and is fitted in telescopic relation as 'v, ''''''''' ~
.f~;3~
Docket6487 a press fit over the outside surface of the base portion 14 and into abutment with the shoulder 14c.
Similarlyt the cylindrical pole portion 15a of the pole 15 is fitted in telescopi.c relation to the sleeve 16 as S a close press fit.
The xemote end of the sleeve 16 is in abutment with the adjacent wall of the shoulder portion 15b. Preferably, the fit between the sleeve and the base is also a close press fit. If desired, a suitable sealant may be applied to the .10 interface between these parts.
The sleeve 16 is formed with a cylindrical portion 16a axially lntermediate the base and the hub, bridging the space therebetween, and formed with an inside diameter essen-tially the same as that of the base and hub, thus forming an intermediate wall portion of the armature cavity 17.
A solenoid armature 20 formed of magnetic materialis received within the cavity 17 of the spool assembly 12 for ` axial movement therein into coaction with the pole 15. A non-magnetic shaft 22 extends axially ~rom one end of ~he armature 20 by which the mo~ement of the armature 20 is transrnitted to the exterior of the solenoid. ~ommonly, the shaft 22 will be connectea to operate the spool of a hydraulic valve or the like.
The interior armature cavity is closed by an end cap 2S 25, the outer diameter of which is received within the case opening. The end cap 25 is provided with a central clearance opening 26 through which the shaft 22 extends while per~itting , hydraulic fluid under pressure to enter into the interiGr of `~ the solenoid cavity. The armature 20 is held and guided in 3~ spaced relation from the cylindrical cavi~y walls by means of ,~
Dock~t 6487 .~
a plurality o longitudinally extending bearing strips 28, preferably four in number at 90 intervals, and pressed into longitudinal recesses formed within the armature. The upper sur~aces of the strips 28 proj~ct a few one-thousands of an inch or less abov,e the surface of the armature 20 and provide for the guidance of the armature within the cavity while assuring close magnetic coupling between the armature, the base ~nd the pole. Longitudinal openings or passageways 30 are formed in underlying relation to the strips 28 and extend axially between the ends of the axmature 20 to prevent hydraulic lock-up of the armature by permitting the flow of fluid there-through from one end of the armature to the other as the ax,mature moves axially within the solenoid.
The end cap 25 is statically sealed at the base 15 by an O-ring 32 on the inside face of the cap. An axial cylindrical portion 25a forms one wall of the interior cavity ~, and defines an abutment for the armature 20, and is thus posi-'' ~ioned radially within the pole portion 15a. An annular face ,",; seal 34 may be provided on the outside surface of the end cap ' 25 by means o~ which the end cap is sealed to a valve housing -~ 20 or the like.
~, It is common to provide external means by which the , armature 2~ may be moved for the purpose of operating the ;; connected valve, and for this purpose a non~magnetic manual ; actuator 35 is received within the base extension 14b. The actuator is provided with an enlarged head 36 in the cavity 17 '~ forming in effect an opposite axial abutment for the armature 20. The actuator 35 extends ou-twardly of the case 10, and ....
support a snap ring 38. A compression spring ~0 is positioned ,~, between the riny 38 and the outex exposed surface of the base 1 .
~8 3~:i Docket 6487 . .o urge ~he actuator into its normally retracted position, as shown. The stem of the actuator is sealed to the base by means of an O-ring 42. An elastomeric boot 44 may be fitted to the remote end of the base portion 14b to cover the other-wise exposed end of the actuator 35.
In order to effectuate a high pressure coil sub-assembly lZ and to join and seal the sleeve 16 to the base 14 and the pole 15 in the regions where these parts are telescoped, the turns of an electric coil 50 axe wound directly on the .; 10 outer cylindrical surface of the sleeve 16. Preferably, a layer 52 of insulating tape is first applied to the outer ~ surface and.the turns o the electric coil are then wound ; directly onto the sleeve between the shoulder portions l~c and 15b, preferably while applying substantial tension to the ~..
15 wire during wincling. Insulating washers 54 isolate the coil 50 from the shoulders 14c and 15b. The amount of tension employed . can vary in accordance with the size of the wire employed and the strength of the wire. The accumulative effect of winding ~: the turns of the coil 50 onto the sleeve 16 results in com-~ 20 pression of ~he sleeve 16 about the ~elescopic portions of the -:.. pole 15 and the hub 14, assuring a fluid-tight joint therebe-tween, and at the same time, assisting materially in resisting ... thP deflection of the spool assembly by reason of the applica-tion of fluid under pressure into ~le interlor of the solenoid.
. 25 The elimination o-f the conventional coi.l form enhances .~. the heat sink capacity of the solenoid. Thus, the turns of the coil 50 are in substantially closer heat transmitting relation to the sleeve 16 than would be the case where a coil form were ~ used. Preferably, the sleeve 16 i.s made of a non-magnetic metal .. ~ 30 having a good heat conductivit~, such as brass, to transmit the heat from the coil 50 to the adjacent structure of the : .
~, G
Docket 6487 .
solenoid. Th~ arrangement is one in which a spool asse~bly is formed free of threaded joints by using economical slip fits. The sleeve 16 is actually in compression and firmly engages the interfitted base and pole. An assembly is formed which maintains its integrity up to 8000 psi or more, permit-; ting continuous operation in the range of 3000 psi or more.
The cylindrical portion 15a of the pole 15 may beformed with any suitable configuration, such as the tapered form shown, to provide a desired linearity in operation. The 0 tapered form shown has particular use as a proportional act-~ uator, and is a preferred embodiment. It is preferred to form ; the end cap 25 of magnetic material to provide specific force curves or operating characteristics, in which case a non-magnetic spacer 60 keeps the armature 20 rom completely closing the gap with the cap and becoming magnetically held.
; However, the cap 25 may also be made of non-magnetic material ; and the spacer 60 omitted. The solenoid may also be operated ~ as a two-position unit, although the employment of the tapered ~ c pole section 15a permits the solenoid to be used as a propor-tional actuator.
The solenoid is free of any sliding or moving seals which imnede the movement of the armature 20. The seals 32 and 34 are static and thus not subject to wear. The one moving seal 42 on the stem of the manual actuator 25 is . . .
infrequenfly used, does not impede the movement of the armature, and is not subject to appreciable wear.
By example only and without limitation, suitable - ~ solenoids in accordance with this invention have employed coils wound as follows:
' . i ~ 3 Docket 6487 (A) 615 turns, No. 22 AWG conductor wound with 15 ounces of tension to provide a 12 volt DC unit, with 2.88 ohms resistance and 36 watts, one-quarter duty.
~ B) 1,204 turns, No. 25 AWG conductor wo~md with 15 ounces of tension to provide a 12 volt DC unit, with 1l.39 ohms resistance and 9 watts, continuous duty.
(C) 1,204 turns, No. Z5 AWG conductor wound with 15 ounces of tension to provide a 24 volt DC unit, with 11.39 ohms resistance and 36 watts, one-quarter duty.
~D) 2,420 turns, No. 28 AWG conductor wound with 12 ounces of tension to provide a 24 volt DC unit, wi~h 45.86 ohms : ` :
; resistance and 9 watts, continuous duty.
(E) 4,718 turns, No. 31 AWG conductor wound with 8 ounces of tension to provide a 110 volt ~C unit, rectified to a 100 volt DC, with 179 ohms resistance and 36 watts, one-quarter duty.
(F) 8,873 turns, No. 34 AWG conductor wound with 4 ounces of tension to provide a llO volt AC unit, rectified to a 100 volt DC unit, with 613 ohms resistance and 9 watts, continuous duty.
The specific strength in psi attributed to the coil 50 on the sleeve 16 may be represented by the formula:
PSI = 2 TS x S. F.; where T = radial wall thickness of coil in inches, S ~ yield strength of wire in pounds per square inch, I. D. = inside diameter of coil 50 in inches, and ; S. F. = space factor of wir~.
Appl~-in~ this formula to the above examples tA) ~ provides the following theoretical burst strength increases in pSi by ' .' -~
Or~
Docket 6487 ;~
reason of the coil 50 on the sleeve 16. (In each calcuation T = .265", S = ]0,000 psi, I.D. = .845" and S. F. were as indicated.) ` (A) 4,272 psi with 22 AWG wire, S. F. = .6811 (B) 4,186 psi with 25 AWG wire, S. F. = .6675 (C) 4,186 psi with 25 AWG wire, S. F. = .6675 (D) 4,191 psi with 28 AWG wire, S. F. = .6683 (E) 4,084 psi with 31 AWG wire, S. F. = .6511 (F) 3,829 psi with 34 AWG wire, S. F. = .6105 It will be noted that while tension, per se, is not a . ~
~; theoretical factor in calculating the burst strength :
provided of a coil, nevertheless the presence of tension is considered to be important since it results in the initial ` compression of the sleeve 16 and thus prestresses the sleeve ,. . .
about the interfitted base and pole regions, and the initial actual deflection of the spool assembly 12 within the operating range of the solenoid will be appreciably less than if the coil 50 were wound with minimum tension.
, . . .
Further, the compression effect advantageously forms a fluid-tight seal between these interfitting parts. In manufacture, it has been found that the I.D. of cavity 17 `- will be somewhat decreased after the coil 50 is wound, at which time it may be suitably rebored or honed precisely to the desired dimension before the solenoid is finally assembled.
Description of Figs. 4-5 The elmination of the conventional coil form - provides a solenoid construction which advantageously may be used with a dry plunger as described in connection with the _9_ `, ~
;36 Docket 6487 present invention. This is particularly true in the construction of a proportional solenoid in which an axial portion of a cylindrical pole is selectively saturated by the movement of an armature in telescopic relation to the pole~ The attachment of the base and the hub as an integral part of the assembly by means of this invention, that is by means of the sleeve and the winding of the turns of the coil thereon, provides an economical and efficient structure having superior heat dissipating characteristics.
The case 110 is formed of magnetic material and has a front flange 111 at the open end of the case. The flange 111 may be as shown in Fig. 3 in connection with the flange 11, or alternatively, it may be provided with external threads for mounting the solenoid, as a cartridge-type r" 15 solenoid.
The coil or spool assembly 112 of the invention is made up essentially of three separate pieces, n~mely, the base 114, the hub or pole 115, and a tubular spacer or ; sleeve 1160 The base and pole are formed of ferrous material and have generally the same configuration as that described in Figs. 1-3. The non-magentic conne~tion sleeve however, may be formed of a length of tubing material which has been accurately cut to a desired length The sleeve thus defines the spaced-apart distance, and accordingly defines a working air gap 116b in the axial space between the hub and the pole. ~ow cost aluminum or brass tubing or the like may be employed for this purpose, which forms a slip fit over the respective cylindrical sections 114a and 115a of the adjacent magnetic parts. The end cap 125 need ~10-' ~
.. .
~4.~ 3 Docket 6~87 not be sealed in a fluid tight manner, although conventional seals may be employed where dust, fluids, or other ;~contaminations are anticipated. The end cap 125 may be a simple press fit into the open end of the case 110, and as ~`5 previously mentioned, may be Eormed of either magnetic or non-magnetic material in accordance with the desired `~'rcharacteristics of the solenoid.
iThe armature 120 is somewhat modified from the armature 2a previously described in that the axial passageways therethrough may also be eliminated.
Additionally, it has been found advantageous to support the armature 120 at its inner end, on a sleeve bearing 128. The bearing 128 has an inner surface mounted on the armature 120 and has an outer surface forming a close running fit with the inside diameter of the cylindrical portion 114a of the base 114. The bearing 128 may be formed of sintered porous bearing metal, such as bronze, and in appropriate cases, impregnated with a desired lubricant. A second sleeve bearing 129, preferably ~ormed of the same material as that 20 of the bearing 128, is supported in the end cap portion 125a and slidably guides the shaft 122, so that the armature 120 is guided at one end by the bearing 128 and is guided at its remote end by the bearing 129 in association with the shaft.
The turns of the electric coil 150 are wound in direct engagement with the ou~er surface of the sleeve 116, and a layer 152 of insulating tape, shown in somewhat exaggerated thickness, in Fig. 4, is preferably applied before winding to provide electrical isolation for the coil 150. The coil 150 is wound in tension into the annular ' ~
"
'~
~.23~6 Docket 6487 space defined by the radial shoulders of the hub and base, and the interfitting outer cylindrical surface of the ~; sleeve, causing the sleeve 116 to be compressed about the interfitted cylindrical sections therein. In this manner, an excellent thermal bond and mechanical connection is formed between the sleeve 116 on the one hand and the interfitted base and pole portions on the other hand.
The movable plunger 35 of Fig. 2 has been omitted.
In its place, a non-magnetic button 135 is inserted with a head 136 received within the armature cavity and positioned .
to come into abutment wlth the armature 120 ln the retracted ` position of the armature, as shown in Fig. ~. The button 135 prevents the armature 120 from coming into direct ~ contact with the base 114.
; 15 It is further understood that the shaft 122 may be extended through the armature 120, or a suitable connection ~, made thereto through an aperture in the a~ial end 114b of the base 114 to provide an electrical feedback signal. One such electrical feedback signal arrangement is shown in the U. S. patent of Myers, No. 3,870,931 issued March 11, 1975, and assigned to the same assignee as this invention.
While the form of apparatus herein described ; constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.
- What is claimed is:
' "~
Claims
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
An electric spool assembly for a dry axial solenoid comprising a magnetic pole, a sleeve formed of non-magnetic tube material, and a magnetic base, said pole having a por-tion received in axial interfitting relation with one end of said sleeve, said base having a portion received in interfitting relation with the opposite end of the sleeve, thereby forming.
a first telescopic joint between said sleeve and said pole at one end of said sleeve and a second telescopic joint between said sleeve and said base at the other end of said sleeve, said sleeve defining an axial air gap between said pole and said base forming an opening, means on the outer surface of said assembly forming an annular coil-receiving space defined at least in part by the outer surface of said sleeve, and an electric coil having turns of wire wound in tension on said sleeve outer surface causing said sleeve to be physically compressed in the regions where said sleeve is telescopically interfitted with said base and said pole thereby thermally and mechanically connecting said sleeve with said hub and base.
The spool assembly of claim 1 in which said base is formed with a radial portion in abutment with one end of said sleeve and in which said pole is formed with a radial portion in abutment with the opposite end of said sleeve, said radial portions defining with said sleeve outer surface said annular coil-receiving space.
A dry solenoid comprising a non-ferrous tubular sleeve hav-ing an outer coil-receiving surface, a base formed of magnetic material telescopically received on an inside surface of said sleeve at one end thereof and having a radial shoulder extending outwardly of said sleeve forming one wall of a coil cavity, a pole of magnetic material telescopically received on said sleeve in spaced relation to said base and having a radial shoulder ex-tending outwardly of said sleeve forming a second wall of a coil cavity, said pole and base having inside diameters defining an axial cavity, an armature, end wall means on said solenoid sup-porting said armature for axial movement in said cavity, and an electrical coil having turns of wire wound in tension on said sleeve compressing said sleeve into firm mechanical and thermally conductive engagement with said base and said pole at the tele-scopic portions therebetween.
An electric spool assembly for a dry axial solenoid comprising a magnetic pole, a sleeve formed of non-magnetic tube material, and a magnetic base, said pole having a por-tion received in axial interfitting relation with one end of said sleeve, said base having a portion received in interfitting relation with the opposite end of the sleeve, thereby forming.
a first telescopic joint between said sleeve and said pole at one end of said sleeve and a second telescopic joint between said sleeve and said base at the other end of said sleeve, said sleeve defining an axial air gap between said pole and said base forming an opening, means on the outer surface of said assembly forming an annular coil-receiving space defined at least in part by the outer surface of said sleeve, and an electric coil having turns of wire wound in tension on said sleeve outer surface causing said sleeve to be physically compressed in the regions where said sleeve is telescopically interfitted with said base and said pole thereby thermally and mechanically connecting said sleeve with said hub and base.
The spool assembly of claim 1 in which said base is formed with a radial portion in abutment with one end of said sleeve and in which said pole is formed with a radial portion in abutment with the opposite end of said sleeve, said radial portions defining with said sleeve outer surface said annular coil-receiving space.
A dry solenoid comprising a non-ferrous tubular sleeve hav-ing an outer coil-receiving surface, a base formed of magnetic material telescopically received on an inside surface of said sleeve at one end thereof and having a radial shoulder extending outwardly of said sleeve forming one wall of a coil cavity, a pole of magnetic material telescopically received on said sleeve in spaced relation to said base and having a radial shoulder ex-tending outwardly of said sleeve forming a second wall of a coil cavity, said pole and base having inside diameters defining an axial cavity, an armature, end wall means on said solenoid sup-porting said armature for axial movement in said cavity, and an electrical coil having turns of wire wound in tension on said sleeve compressing said sleeve into firm mechanical and thermally conductive engagement with said base and said pole at the tele-scopic portions therebetween.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US825,594 | 1977-08-18 | ||
| US05/825,594 US4153890A (en) | 1976-04-30 | 1977-08-18 | Coil compressed solenoids subassembly |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1123036A true CA1123036A (en) | 1982-05-04 |
Family
ID=25244415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA309,248A Expired CA1123036A (en) | 1977-08-18 | 1978-08-14 | Electric spool for dry axial solenoid |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5442648A (en) |
| CA (1) | CA1123036A (en) |
| DE (1) | DE2834725A1 (en) |
| FR (1) | FR2400759A2 (en) |
| GB (1) | GB1604480A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6116662Y2 (en) * | 1981-01-09 | 1986-05-22 | ||
| JPS57141047A (en) * | 1981-02-20 | 1982-09-01 | Pioneer Electronic Corp | Device for detecting stop of reel rotation in cassette deck |
| DE3309904A1 (en) * | 1983-03-18 | 1984-09-20 | Mannesmann Rexroth GmbH, 8770 Lohr | ELECTROMAGNET AND SOLENOID VALVE |
| GB2156158B (en) * | 1983-12-22 | 1987-06-17 | Mac Valves Inc | Solenoid assembly |
| FR2697607B1 (en) * | 1992-10-30 | 1994-12-02 | Bendix Europ Services Tech | Electromagnetic valve control device. |
| JP2021163796A (en) * | 2020-03-31 | 2021-10-11 | 豊興工業株式会社 | electromagnet |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3040217A (en) * | 1959-08-10 | 1962-06-19 | Clary Corp | Electromagnetic actuator |
| CH421297A (en) * | 1964-04-23 | 1966-09-30 | Peter Dipl Ing Isliker | DC magnet |
| GB1155382A (en) * | 1965-07-13 | 1969-06-18 | Expert Ind Controls Ltd | Solenoid Actuated Devices |
| US3900822A (en) * | 1974-03-12 | 1975-08-19 | Ledex Inc | Proportional solenoid |
| FR2270667A1 (en) * | 1974-05-08 | 1975-12-05 | Inst Televidenia Radiovescha | Electromagnet latching means for solenoid plunger - gives reduced dimensions and energy consumption and faster response |
| US3921111A (en) * | 1974-09-25 | 1975-11-18 | Marotta Scientific Controls | Solenoid actuator for high pressure valve |
| DE2640612C3 (en) * | 1976-09-09 | 1982-01-21 | Siemens AG, 1000 Berlin und 8000 München | Solenoid plunger magnet system and process for its manufacture |
-
1978
- 1978-05-30 GB GB2454878A patent/GB1604480A/en not_active Expired
- 1978-07-26 FR FR7822185A patent/FR2400759A2/en active Pending
- 1978-08-08 DE DE19782834725 patent/DE2834725A1/en not_active Ceased
- 1978-08-14 CA CA309,248A patent/CA1123036A/en not_active Expired
- 1978-08-17 JP JP10042978A patent/JPS5442648A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1604480A (en) | 1981-12-09 |
| JPS5442648A (en) | 1979-04-04 |
| JPS6140121B2 (en) | 1986-09-08 |
| FR2400759A2 (en) | 1979-03-16 |
| DE2834725A1 (en) | 1979-03-01 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |