US2383332A

US2383332A - Solenoid construction

Info

Publication number: US2383332A
Application number: US403352A
Authority: US
Inventors: Raymond S Miller; Seidel Kamill
Original assignee: Vickers Inc
Current assignee: Vickers Inc
Priority date: 1941-07-21
Filing date: 1941-07-21
Publication date: 1945-08-21
Anticipated expiration: 1962-08-21

Description

Aug- 21, 1945 R. s. MILLER ETAL 2,383,332

SOLENOID CONSTRUCTION Filed Julif 2l, 1941 2 Sheets-Sheet l n] i Fay/mon] .S Mil/er Aug. 2l, 1945. R. s. MILLER ETAL SOLENOID CONSTRUCTION- Filed July 21, 1941 2 ysheets-sheet 2 INVENTOR.

Fqymma' JT /V/'l/er 71' ami/ Seidel maf/Mw "other magnetic losses.

Patented ug.`2l, 1945 UNITED STATES PATENT oFFlcE soLENom coNs'raUc'rroN Raymond S. Miller and Kamill Seidel. Detroit,

Mich., assignors to `"ickers, Incorporated, De-

troit, Mich., a corporation of Michigan Application .my 21, 1941, serial No. 403,352

' 7 claims. (ci. irs-341) construction but none of these has been completely successful. It is an object of the present invention to provide a solenoid which has a suitable housing construction from the point of view of strength and which has a novel magnetic circuit for the magnetic flux of the solenoid.

Another object of the invention is the construction of a solenoid in which. the physical dimensions, weight and operating temperature are at a minimum for a definite amount of pounds pull or torque. A

In solenoid construction it is extremely desirable to use a magnetic circuit made upof thin v laminae in order to reduce the eddy currents and keep the iron loss at a minimum. On the other hand, it is desirable to keep the magnetic circuit as short as possible and also to provide a housing along with the circuit which protects the electric coil both from the point of view of conducting the heat away from the coil and keeping air and Figs. 2 and 3 are sectional views taken on lines 2-2 and 3 4, respectively, of Fig. l.

Figs. 4 and 5 are end and side elevations re-A spectively of the magnetic material which goes into the solenoid.

Fig. 6 illustrates the condition of the housing and magnetic material prior to the machining operation.

Fig. 7 is asectional view of the construction of Fig. 6.

Fig. 8 is an end view of the housing after machining, showing the recess which receives the solenoid in assembly.

Fig. 9 `is a partial perspective of the end plate showing the detailed construction thereof.

In Fig. 4, four blocks, A, B, C and D are shown arranged in spaced relation around an imaginary axis E. These blocks are held in'their respective positions by angles i0 and braces Il.

dirt out of the operating mechanism. The so' 30 y ing the casing material into such mold while in a molten or plastic state and then allowing it to set called window frame type of solenoid construction is well known, that is, the type in which a frame of laminae is usedto surround the coil. Another type has recently come into use and that is the solenoid circular iron housing, this latter type has the advantages of providing a complete covering for the construction but has caused considerable loss from heat due toeddy currents and The present invention contemplates a solenoid housing which combines 40 the advantages of the laminated structure with the solenoid housing structure and which achieves the ideal result of a minimum eddy current loss,

low iron loss, a short magnetic path, low operat- 4 ing temperature, and light weight. There are numerous other advantages which.l iiow from the construction to be herein described but no attempt made here to enumerate all the" advantages.

Other objects and features of the invention will These blocks A, B, C and'D arevformed of a magnetic material and may be of solid iron. They are preferably formed of L-shaped pieces of laminations of iron as shown in the drawings. The next step in the manufacture of the housings is the forming of a casing around the magnetic blocks. This casing is shown at l5, Fig. 6. This casing may be applied around the blocks in a die-casting operation or a molding process. Fundamentally, the step consists of placing the blocks within some kind of a mold and either forcing or pouror harden. A core is used to eliminate the necessity for boring out the entire center. The material forming the housing I5 is to be a non-magnetic material. Ilf metal is used, aluminum has been found to be suitable. Another suitable subvstance is the class of materials which is commonly called plastics, one of which is Bakelite.

Other suitable means may be used to space and arrange the blocks prior to the molding process. Afterl the casting or molding operation, the block is machined to have an internal bore I6, as shown in Fig. 8. The bore does not pass coml pletely through the block but terminates in a Wall Il which has an aperture i8. The magnetic circuit of the housing is completed by two additional blocks of laminated material F and G, shown in Fig. 2, arranged in transverse relation and jointed 4together in 'such a Way that the ends thereof will register with the end blocks A, B, C and D. A cap 20 is provided with a recess for receiving the members F and G and for positioning the same.

A magnetic pole piece 2| is held against the center portion of the blocks by a bolt 22. The cap The cap 2l with the pieces F and G completes s the magnetic circuits at one end of the assembly while the other ends of the circuits are completed by the portions of blocks A, B, C and D which make up wall l1 (Fig. 8). While the arrangement described is preferred, it will be seen that separate end pieces could be used at both ends of the circuits.

A solenoid winding 24 is received in the bore I6 of the housing I5. A non-magnetic sleeve 2l, for example of brass, is inserted within the solenoid Winding. This sleeve is sealed at one end by a compressible gasket 2G and atthe other end by a. compressible gasket 21. These gaskets are made slightly oompressible to permit the' parts to be drawn tightly together in connection with a member 28a. which forms part of the complete assembly and may, for example, be a body of a valve. Within the sleeve 25 is the slotted solenoid core 28 which reciprocates back and forth when the solenoid is energized and may be connected to or integral with the movable member of a valve. Suitable lead wires are taken from the solenoid core through an opening 29 in the calp 20, see Fig. 2. The ends of the members F and G, are positioned in openings 30 machined in the cap 2l (see Fig. 9). It will thus be seen that there is formed a solenoid assembly in which the solenoid core 28 and the inside of the sleeve 25 are sealed from the solenoid. This prevents any oil or foreign matter which may be in the sleeve fromleaking in the winding. I-f desired the members F and G mayalso be cast into the cap 20.

A soft washer 35 is placed =between members i and 2| to seal the inside of the solenoid from dirt and dust. This washer is preferably of the soft material which will permit the bolts 23 t0 tighten the members F and G tightly against the ends of the members A, B, C and D of housing Il. It also'permits the sealing of the compressible seals 28 and 21.

It will be seen that the above described construction provides many paths for the magnetic flux and, in addition, it can ow in more than one plane. The path, however, of the ux is a short path with a. minimum of air gaps. In fact, the only air gaps that exist are those between the members A, B, C and D and the transverse G and F. Since this air gap can be reduced to a minimum by the forcing of the parts together in assembly, it does not involve a serious loss. Since these air gaps are reduced to a minimum by the forcing of the parts together in assembly,

. the magnetizing current is reduced to a minimum Lthereby diminishing the no-load losses considerably. Therefore, the windings of the coil can be maintained at a minimum and more of the effective current put' into the solenoid is transferred into actual pull. In addition, it will be seen that the solenoid is completely protected from outside dirt and air and that the use of a light-material for the housing, such as aluminum or plastic will reduce the overall weight considerably. In addition, the laminations are rigidly secured against vibration and loosening.

We claim:

1. A solenoid construction comprising a casing of `non-magnetic material, fields of laminated magnetic material embedded in said casing in spaced relation around a central bore therein,v a solenoid winding in said bore, means at the end of said winding in said bore for forming an end pole comprising longitudinal blocks of laminated magnetic material arranged in y transverse relation and positioned whereby the ends thereof register with the magnetic material in said main housing, a magnetic pole piece on said blocks, and a cap for maintaining said blocks in position relative to said main housing.

2. A solenoid construction comprising a casing of non-magnetic material such as aluminum. fields of laminated magnetic material embedded in said casing in spaced relation around a central bore therein, a solenoid winding in said bore, meansat the end of said winding in said bore for forming an end pole comprising longitudinal blocks of laminated magnetic material arranged in transverse relation and positioned whereby the ends thereof register with the magnetic material in said main housing, a magnetic polel piece on said blocks, and a cap for maintaining said blocks in position relative to said main housing, and means holding said cap in place comprising bolts extending from said cap into said embedding material independently of said field laminations.

3. A solenoid construction comprising a casing of non-magnetic material such as aluminum, elds of magnetic material embedded in said cas' ing in spaced relation around a central bore therein, said material comprising L-shaped laminations arranged inv groups, a solenoidwinding in said bore, means at the end of said winding in said bore foxl forming an end pole comprising longitudinal blocks of magnetic material arranged in transverse relation and positioned whereby the ends thereof register with the magnetic material in said main housing, a magnetic pole piece on said blocks, and means formed of non-magnetic material for maintaining said blocks in position relative to said housing.

4. The method of forming a solenoid housing which comprises arranging corner to corner L- ends of elongated blocks of magnetic material parallel to, and in spaced relation around, an imaginary locus, surrounding said pieces in a non-magnetic material in a plastic state, hardening said `material to embed said blocks firmly, and machining blocks and the embedding material to provide an opening to receive a solenoid winding. f

5. The method of forming a housing for an electrical device dependent on electrical fields for operation which comprises arranging pieces of magnetic material in spaced relation around an imaginarylocus. fastening said pieces together with suitable means to hold them in spaced relation, surrounding said pieces in a non-magnetic material in a molten or plastic state, hardening said material to embed sai-d blocks firmly, and

`machining the magnetic material and the embedding material to provide an opening to receive an electrical element.

6. A housing for a cylindrical solenoid winding comprising a plurality of sets of L-shaped iron laminae arranged in opposed pairs around an axis, a non-magnetic material embedding said laminae, one leg of each lamina extending parsaid inierlocked laminae Within said Windcently spaced sets to maintain the same in position, means embeddingV said angle means and said sets of leaving the inward feces oi` 'thelaminneexposed,l.pluralityotinterloeked` setsotlaminaeurang'edndiellyoitheaxis,each

set having its ends positioned adjacent the' .ends

of the opposed pairs of L-shsped lamine, and? means on said interiocked laminae and within said winding to' form l pole piece for s solenoid plunger operating within said winding.

RAYMOND B. MILLER. KAMILL BEIDEL.