Reference / Paper · 1984
US Patent 4,443,775 — Fujitani et al., Solenoid Actuator (1984)
Slits in the solenoid frame against eddy-current loss.
- solenoid
- eddy current
- laminated frame
Reference / Paper · 1984
Slits in the solenoid frame against eddy-current loss.
United States Patent (19) 11 45 Fujitani et al. 4,443,775 Apr. 7, 1984 (54) SOLENOID ACTUATOR 75) Inventors: Hidetsugu Fujitani, Kasukabe; Tsuneo Ishigaki, Sugito; Tetsuro Tokuda, Misato, all of Japan 73 Assignee: Shoketsu Kinzoku Kogyo Kabushiki Primary Examiner-Harold Broome Attorney, Agent, or Firm-Oblon, Fisher, Spivak, 21 Appl. No.: 337,501 57 22 Filed: Jan. 6, 1982 30 Foreign Application Priority Data Jan. 31, 1981 JP Japan ............................. 56-13009(U Oct. 6, 1981 JP Japan ........................... 56-148431U) 51) Int. Cl. .............................................. HOF 3/00 52 U.S. C. .................................... 335/281; 335/251; A solenoid actuator of high performance comprising a coil surrounded externally with a magnetic frame and having a stationary core disposed therein, with a mov able core attracted to the stationary core upon energiz ing the coil being disposed axially slidably, wherein the magnetic frame comprises a pair of magnetic frame parts each fabricated from a sheet material by bending the sheet so as to define a top plate and a bottom plate integrally joined with a side plate for covering the top, bottom and side of the coil, and the pair of magnetic frame parts are assembled to each other with their top plates and bottom plates being overlapped to each other, to thereby provide simplified structure and easy assembling. FOREIGN PATENT DOCUMENTS 1489622 4/1971 Fed. Rep. of Germany . McClelland & Maier Kaisha, Tokyo, Japan 336/212 58 Field of Search ............... 335/281, 251, 255, 202, 335/278; 174/35 D; 220/DIG. 25, 3.94, 4 C; 206/818; 336/83, 212; 310/42,254; 29/609 56 References Cited U.S. PATENT DOCUMENTS 3,145,327 8/1964 Thayer, Jr. et al. ................ 335/251 3,523,362 8/1970 Wilk ...................................... 29/609 ABSTRACT 5 Claims, 9 Drawing Figures SNSS SaëS Sezki 52 N SSSSSS S2% S2, waxa SS 2 .2 s X Za a. a. SS % NS 2N 22 222 22 S V N3 N3SSS WSA. NSS. U.S. Patent Apr. 17, 1984 Sheet 1 of 4 PRIOR ART 4,443,775 U.S. Patent Apr. 17, 1984 Sheet 2 of 4 4,443,775 NN "Sit S 31 2. . 32 Y WZ- 7N N V12 SW3-4 SAS-48 WN S1 \% 37- / 2-42 Y. N U.S. Patent Apr. 17, 1984 Sheet 4 of 4 4,443,775 4,443,775 SOELENOED ACTUATOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention concerns a solenoid actuator for use 2 A futher object of this invention is to provide a sole noid actuator wherein slits are recessed in the top plates and the bottom plates of magnetic frame parts that can suppress the generation of eddy current and permit effective utilization of available electrical power. A still further object of this invention is to provide a Solenoid actuator wherein said slits and the projections formed on the end plate of the bobbin are engaged to with electromagnetic valves adapted to change the flowing direction of fluid mainly by electromagnetic each other for permitting accurate assembling of a pair operation force. 10 of magnetic frame parts, as well as recesses and protru 2. Disclosure of Prior Art are provided to the side edges of the slits and side A magnetic frame for a solenoid actuator, for exam sions the projections respectively to enable the positioning ple, as shown in FIG. has heretofor been known. The of of the pair of the magnetic frame parts in assembling magnetic frame comprises a frame main body 10 having and disassembling directions by the engagement there a top plate 11 integrally joined with right and left side 15 between. plates 2, 3, a bottom plate 14 attached between the The foregoing objects can be attained by the solenoid lower ends of the side plates 12, 13 by engaging projec actuator to this invention having a coil tions 17, 7 provided respectively at the lower ends of formed byaccording applying windings around a bobbin and a the side piates 2, 13 into recesses 18, 19 formed in magnetic frame around the coil, with a station magnetic flux plates 15, 16 and a magnetic flux plate 20 20 ary core being disposed disposed and a movable core overlapped with the top plate 11. The thickness for the attracted to the stationarysecurely core upon the coil portion of the top plate 11 overlapped with the mag being disposed axially slidably at theenergizing center of the coil, netic flux plate 20 and that of the bottom plate E4 over wherein the magnetic frame comprises a pair of mag lapped with the magnetic flux plates 15, 16 are increased frame parts each fabricated from a ferromagnetic by the overlapping so that the joining areas between as netic sheet by bending the both ends thereof so as to each of the central apertures 21, 22 formed in these definematerial a top plate and a bottom plate integrally joined to plates and a stationary core or a movable core to be the both ends of a side plate respectively for covering inserted therein is made equal to or greater than the the top, bottom and side of the coil, and the pair of cross sectional area S of the core. In such a magnetic magnetic frame parts are assembled with their top plates frame, however, air gaps are present at the abutments 30 and the bottom plates being overlapped to each other. 23, 24, 25 between the lower ends of the side plates 12, In the magnetic frame comprising the pair of mag 3 and the magnetic flux plates 15, 16 and the like that netic frame parts, each of the overlapping size between form great magnetic resistance to worsen the perfor the top plates and between the bottom plates is de 2C. creased within a range capable of affording a sufficient SUMMARY OF THE INVENTION 35 magnetic flux path, a gap is formed between the leading end of the top plate or the bottom plate of one magnetic This invention has been made in view of the forego frame part and the side plate of the other magnetic ing and an object thereof is to provide a solenoid actua frame part in the magnetic frame, a stepped portion is tor of high performance with less magnetic loss wherein provided on the end plate of said bobbin for engage a magnetic frame comprises a pair of magnetic frame 40 ment with the gap, and a partition chamber is formed in parts whose top plates and bottom plates are overlapped the stepped portion capable of containing the connec to each other for eliminating the abutments and thus the tion portions between the lead wires and windings air gaps inevitable so far in the conventional magnetic while isolating them from the windings, whereby con frame. nection works between the windings and the lead wires Another object of this invention is to provide a sole- 45 are made possible in the partition chamber. Slits are noid actuator wherein the magnetic frame can be manu recessed in the top plates and the bottom plates in the factured simply by applying press work to ferromag magnetic frame parts for elimination of eddy current netic sheet materials thereby enabling to reduce the loss, whereby effective utilization of available power manufacturing cost. suppy is enabled. Further, projections are provided on Another object of this invention is to provide a sole- 50 the upper and the lower end plates of the bobbin for noid actuator wherein a gap is provided between the engagement with the slits formed in the top plate and top plate or the bottom plate of one magnetic frame part the bottom plate each disposed inner side in the mag and the side plate of the other magnetic frame part netic frame, whereby assembling of the pair of magnetic necessarily formed as the result of decreasing the over frame parts can be facilitated. Furthermore, recesses are lapping width between the top plate and the bottom 55 formed to the side edges of the slits and protrusions for plate and the gap can be effectively utilized as the space engagement with the recesses are formed to the sides of for the connection of lead wires. said projections to permit the positioning of the pair of A further object of this invention is to provide a magnetic frames in the assembling and disassembling solenoid actuator wherein a partition chamber is pro direction. vided in a stepped portion on one end plate of a bobbin 60 BRIEF DESCRIPTION OF THE DRAWINGS for engagement with said gap to conduct connection works between windings and lead wires in the chamber FIG. is a perspective view of a conventional mag to thereby prevent the occurence of electrical accidents netic frame for use with solenoid actuators, FIG. 2 is a perspective view of a magnetic frame in such as short-circuit caused by the contact with wind ings and eiiminate the use of additional space around the 65 the first embodiment of this invention, FIG. 3 is a cross sectional view of a solenoid actuator periphery of the coil for the connection works, to en able effective utilization for the winding space of the having the magnetic frame shown in FIG. 2 incorpo coil. rated therein, 4,443,775 3 FIG. 4 is a perspective view of a magnetic frame in the second embodiment of this invention, FIG. 5 is a cross sectional view of a solenoid actuator having the magnetic frame shown in FIG. 4 incorpo rated therein, FIG. 6 is a perspective view of an auxiliary magnetic 4. resiliency of a return spring or the like (not shown) exerted by way of a push rod 46 upon energizing the coil 41. In this case, while the attraction force between the movable core 45 and the stationary core 44 is in creased gradually as the former approaches the latter in a range where the lower end face 47 of the movable frame used in the solenoid actuator shown in FIG. 5, core 45 does not come closer to the top end at the annu FIG. 7 is a cross sectional view of a bobbin used in lar wall 48 of the stationary core. Then, when the lower the solenoid shown in FIG. 5, end face 47 of the movable core 45 further approaches O the stationary core 44 exceeding the top end of the FIG. 8 is a plan view thereof, and FIG. 9 is a perspective view of a magnetic frame in annular wall 48 thereof, the attraction force between the third embodiment of this invention. the movable core 45 and the annular wall 48 of the stationary core 44 comes to contain such a component DESCRIPTION OF THE PREFERRED EMBODIMENT as opposing to the attraction force between the lower 15 end face 47 of the movable core 45 and the opposing FIG. 2 and FIG. 3 show the first embodiment of this upper surface of the stationary core 44. As the result, invention, wherein a magnetic frame 30 comprises a the attraction force between the cores is made almost pair of magnetic frame parts 31, 32 formed from ferro constant in this range, that is, a proportional relation is magnetic metal sheets such as iron sheets of a uniform established between the attraction force and the current thickness by bending them generally each in a U-shaped 20 value irrespective of the moving stroke of the movable shape and engaging them to each other. The magnetic frame part 31 comprises a top plate 33 and a bottom core 45. If the movable core 45 further approaches the plate 35 integrally joined respectively at the upper and stationary core 44, the attraction force between them is lower ends of a side plate 37 for covering the upper increased rapidly whereby the above proportional rela surface, the bottom surface and the side surface of a 25 tion is lost. Accordingly, a spacer 49 is put between the bobbin 42 in a coil 41 as shown in FIG. 3. The other cores 44 and 45 so as to restrict the stroke of the mov magnetic frame part 32 comprises a top plate 34 and a able core 45. FIG. 4 and FIG. 5 shows the second embodiment of bottom plate 36 integrally joined respectively to the upper and lower ends of a side plate 38 for covering the this invention, wherein a magnetic frame 50 comprises bobbin 42 in the coil 41 in the same manner. The length 30 magnetic frame parts 51, 52 of a same configuration. of the side plate 37 for the magnetic frame part 31 is The magnetic frame parts 51, 52 having side plates 57, made greater than that of the side plate 38 of the other 58 of a same length are assembled to each other by magnetic frame part 32 by twice of the plate thickness. abutting to overlap the top plate 53 and the bottom plate Accordingly, the magnetic frame parts 31, 32 are assem 55 of one magnetic frame part 51 on the upper surfaces bled in such a way that the former contains, in its inside, 35 of the top plate 54 and the bottom plate 56 of the other the latter with the top plate 33 being overlapped to the magnetic frame part 52 respectively. Apertures 63, 64 upper surface of the top plate 34 and with bottom plate are formed in the overlapped portions of them for fit 35 being overlapped to the lower surface of the bottom ting therein a guide pipe 62 through which a stationary plate 36. Apertures 39, 40 are formed through the top core 60 and a movable core 61 attracted to the station plates 33, 34 and the bottom plates 35, 36 respectively. ary core 60 are engaged while aligned with the center of The joining area between each of the apertures 39, 40 the coil 59 (FIG. 5). Slits 65, 66 are recessed from the and the stationary cores 43, 44 to be inserted to fix middle of the end edges of the top plates 53, 54 to the therein (shown in FIG. 3) is made equal to or greater peripheral edges of the aperture 63 respectively and slits than the effective cross sectional area S of the core, that 67, 68 are recessed from the middle of the edges of the is, it is set so as to satisfy the following relation: 45 bottom plates 55, 56 to the aperture 64 respectively for elimination of eddy current loss. Recesses 69, 70 are Ss2ardt, formed respectively to the slits 66, 67 in the top plate 54 and the bottom plate 55 disposed to the inner side in the whered represents the diameter for the apertures 39, 40 magnetic frame 50. and t represents the plate thickness for the magnetic 50 The overlapped length 1 between the top plates 53, 54 frame parts 31, 32. between the bottom plates 55, 56 in the magnetic The plate material employed has such a dimension as and frame part 51 and the magnetic frame part 52 can be set to satisfy the following relation: to a desired small size within such a range as can include the apertures 63, 64 at the center of the overlapped where w represents the plate width for the magnetic 55 areas and afford a sufficient magnetic flux path, thereby leaving gaps 71, 72 between each of the side plates 57, frame parts 31, 32. FIG. 3 shows an embodiment wherein the magnetic 58 and each of their opposing top ends of the top plate frame referred to above is applied to a so-called propor 54 and the bottom plate 55 disposed to the inner side in tional solenoid actuator capable of producing output in the magnetic frame 50 respectively. The coil 59 comprises a bobbin 80 having auxiliary proportion to the value of electrical current. To the center of the coil 41 surrounded with the magnetic magnetic frames 82, 83 made of flanged ferromagnetic frame 30, are disposed stationary cores 43, 44 opposing material fitted at the upper end and the lower ends to the inner sufaces of the apertures 39, 40 formed in top thereof, as shown in FIG. 6, and windings 81 wound plates 33,34 and the bottom plates 35,36, and a movable around the bobbin 80. As shown in FIG. 7 and FIG. 8, core 45 to be attracted to the stationary core 44 upon 65 each pair of resilient projections 86, 86 and 87, 87 is energizing is disposed axially slidably. formed at the upper and the lower surfaces of flanged In the proportional solenoid actuator, the movable end plates 84, 85 of the bobbin 80 at positions symmetri core 45 is attracted to the stationary core 44 against the cal with each other to the axial center of the bobbin for 4,443,775 6 define a top plate and a bottom plate integrally fitting engagement with the slits 66, 67 at the top plate connected to the both ends of a side plate respec 54 and the bottom plate 55 disposed to the inner side of tively for covering the top, bottom and side of the the magnetic frame 50 respectively. Protrusions 88, 89 coil, said top and bottom plates of said magnetic are formed to the side of the projections 86, 87 for en frame parts each defining a leading edge opposite gagement with the recesses 69, 70 respectively, the integral connection thereof to the respective whereby the accurate assembling for the magnetic side plate; frame parts 51, 52 is enabled due to the engagement said pair of magnetic frame parts assembled with their between the projections 86, 87 and the slits 66, 67 as top plates and the bottom plates being overlapped well as the positioning is attained for the magnetic frame parts 51, 52 in the assembling and disassembling 10 to each other, with the overlap between said top directions due to the engagement between the protru plates and between said bottom plates selected to sions 88, 89 and the recesses 69, 70. The auxiliary mag afford a sufficient magnetic flux path and to form a netic frames 82, 83 are provided for reinforcing the gap for containing connection portions of lead bobbin 80 molded from synthetic resin, as well as for wires for making electrical connection to said increasing the cross sectional area of the magnetic flux 15 windings, said gap formed between the leading path between the stationary core 60 and the magnetic edge of a selected one of the top and bottom plates frame 50 and between the movable core 61 and the of one of said frame parts and the side plate of the magnetic frame 50 to decrease the magnetic resistance other frame part; and therebetween. Further, a step 90 is formed on the upper said bobbin further comprising a stepped portion on a end plate 84 of the bobbin 80 for engagement with the 20 selected of the end plates thereof to define a parti gap 71 formed within the magnetic frame 50. Partition tion chamber, said stepped portion disposed in said chambers 93, 94 are formed within the step 90 for con gap, said partition chamber adapted to contain said taining connections between the both ends of the wind connection portions between said lead wires and ing 81 and the lead wires 91 from a power source while said windings to isolate said lead wires from said 25 isolating the connection portions 92 from the winding windings except for said connection portions. 8. 2. In the drawing, reference numeral 95 represents syn 1ng: A solenoid actuator according to claim 1, compris thetic resin for molding the coil 59 together with the said magnetic frame parts having slits recessed in the magnetic frame 50. top plates and in the bottom plates thereof for elim In the solenoid actuator having the foregoing consti 30 inating eddy current losses; and tution, when current is supplied to the coil 59 through said upper and lower end plates of said bobbin having the lead wires 91, a magnetic circuit is established in the projections for engaging the slits formed in the top route from the magnetic frame 50 passing through the and bottom plates of said frame parts. stationary core 60 and the movable core 61 and to the 3. The solenoid actuator of claim 2, comprising: 35 magnetic frame 50, whereby the movable core 61 is said slits of said top and bottom plates of said frame attracted to the stationary core 60. In this case, no par parts defining side edges having recesses formed ticular troubles will occur if no close contacts are therein; and formed between the top plate 53, 54 and between the said projections of said top and bottom end plates of bottom plate 55, 56 to each other in the magnetic frame said bobbin disposed in engagement with said re parts 51, 52, since the magnetic flux circulates passing 40 cesses formed in said side edges. between the top plates 53, 54 and the stationary core 60 4. A solenoid actuator comprising: and between the bottom plates 55, 56 and the movable a coil formed by applying windings around a bobbin core 61. including top and bottom end plates; FIG. 9 shows the third embodiment of this invention, frame comprising a pair of magnetic frame wherein a magnetic frame 100 comprises a pair of mag 45 a magnetic parts each fabricated from a ferromagnetic sheet netic frame parts 101, 102 having a top plate 103 and a material by bending the both ends thereof so as to bottom plate 105, and a top plate 104 and a bottom plate define a top plate and a bottom plate integrally 106 respectively, each top end of which is formed into connected to the both ends of a side plate respec an arc-shaped circumference within such a range as tively for covering the top, bottom and side of the 50 capable of providing a required area for the cross sec coil, said top and bottom plates of said magnetic tion of the magnetic flux path. Slits 107, 08, 109, 110 frame parts each defining a leading edge opposite are recessed in the same manner as in foregoing embodi the integral connection thereof to the respective ments for elimination of eddy current loss. The slits 108, side plate; 109 may also be utilized for setting the bobbin by engag of magnetic frame parts assembled with their ing therein those projections formed on the bobbin of 55 saidtoppair plates and the bottom plates being overlapped the coil in the same manner as shown in the second to each other, with the overlap between said top embodiment. plates and between said bottom plates selected to In each of the foregoing embodiments, it is desired to afford a sufficient magnetic flux path and to form a join the overlapped top plates and the bottom plates to gap for containing connection portions of lead each other by spot welding or the like for minimizing 60 wires for making electrical connection. to said the air gaps therebetween. windings, said gap formed between the leading What is claimed is: edge of a selected one of the top and bottom plates 1. A solenoid actuator comprising: of one of said frame parts and the side plate of the a coil formed by applying windings around a bobbin 65 other frame part; including top and bottom end plates; said magnetic frame parts having slits recessed in the a magnetic frame comprising a pair of magnetic frame top plates and in the bottom plates thereof for elim parts each fabricated from a ferromagnetic sheet inating eddy current losses; and material by bending the both ends thereof so as to 5 4,443,775 7 8 said upper and lower end plates of said bobbin having parts defining side edges having recesses formed therein; and projections for engaging the slits formed in the top said projections of said top and bottom end plates of and bottom plates of said frame parts. said bobbin disposed in engagement with said re 5. The solenoid actuator of claim 4, comprising: 5 cesses formed insk said side edges. & k e k said slits of said top and bottom plates of said frame 10 15 20 25 30 35 45 50 55 60 65