CA1045796A - Manufacture of compacted coils - Google Patents
Manufacture of compacted coilsInfo
- Publication number
- CA1045796A CA1045796A CA229,242A CA229242A CA1045796A CA 1045796 A CA1045796 A CA 1045796A CA 229242 A CA229242 A CA 229242A CA 1045796 A CA1045796 A CA 1045796A
- Authority
- CA
- Canada
- Prior art keywords
- coil
- mandrel
- wire
- mandrels
- coils
- 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
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
- Manufacture Of Motors, Generators (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Insulating Of Coils (AREA)
Abstract
A B S T R A C T
A method of producing a compact electric coil such as a voice coil for loudspeakers, whereby a coil member is wound of ordinary round wire having a coating of a thermoplastic or thermosetting bonding material, whereafter the coil member mounted on a mandrel is heated together with the mandrel and thereafter cooled from its outside so as to crimp around the mandrel while this is still warm and expanded. Hereby the round wire will be forced inwardly with high force so as to get cross sectionally deformed to fill out the available space to a very large degree, and the bonding material sets so as to hold the coil in its compacted shape whereby a coil of high rigidity and heat conductivity is produced. The coil is easily retractable from the mandrel upon further cooling of the latter.
A method of producing a compact electric coil such as a voice coil for loudspeakers, whereby a coil member is wound of ordinary round wire having a coating of a thermoplastic or thermosetting bonding material, whereafter the coil member mounted on a mandrel is heated together with the mandrel and thereafter cooled from its outside so as to crimp around the mandrel while this is still warm and expanded. Hereby the round wire will be forced inwardly with high force so as to get cross sectionally deformed to fill out the available space to a very large degree, and the bonding material sets so as to hold the coil in its compacted shape whereby a coil of high rigidity and heat conductivity is produced. The coil is easily retractable from the mandrel upon further cooling of the latter.
Description
~04S'796 The present invention relates to electric coils and more particularly to the production of compact coils in which the space occupied b~ the windings is filled out as far as possible with the winding material itself, e~gO coils in which the so-called space factor is highO Especially in voice coils ~or loud speakers it is important that the coil is as compact as possible9 since the air gap in which the coil works should be as narrow as possible, but also in other coil devices such as transformers it may be generally desirable to use compact coils also because a good heat con-ductivity of the coil is desirableO An associated problem is that the windings should be bonded together by a suit-able binding material such as a thermoplastics, and for making a compact coil, o course, it should be ensured that the desired high space factor is not counteracted by an unnecessary surplus of binding material between the windingsO
Usually the wire is coated with a thin layer of the binding material, and the ready wound coil is subjected to a heat treatment whereby the coatings o~ the juxtapposed wire port-ions ~loat together so as to thereafter provide a firm bond-ing of the windings~ An easy manner o providing the nece5-sary heat is to connect the terminals o the coll with a current source so as to use the coil l~sel~ as a heater elementO
~ relatively good space factor is obtainable with the use o~ a thln bonding material coating and by winding the coil in such a manner that each wire portion is rested against two underlying wire portions and not on the top of one under-lying wire portion~ A still better space factor would be obtainable with the use of wire of rectangular or hexagonal cross section, but such a wire is more expensive than a
Usually the wire is coated with a thin layer of the binding material, and the ready wound coil is subjected to a heat treatment whereby the coatings o~ the juxtapposed wire port-ions ~loat together so as to thereafter provide a firm bond-ing of the windings~ An easy manner o providing the nece5-sary heat is to connect the terminals o the coll with a current source so as to use the coil l~sel~ as a heater elementO
~ relatively good space factor is obtainable with the use o~ a thln bonding material coating and by winding the coil in such a manner that each wire portion is rested against two underlying wire portions and not on the top of one under-lying wire portion~ A still better space factor would be obtainable with the use of wire of rectangular or hexagonal cross section, but such a wire is more expensive than a
- 2 -round wire, and in automatic coil winding problems will occur due to twist tendencies of the wire, whereby the space factor would not at all be goodO
The invention relates to a method of producing compact electric coils wound of insulated wire of round cross section~
al shape~ and i-t is the purpose of the invention to provide a method whereby an improved space factsr is obtainableO
According to the invention the coil, upon being wound, is maintained or mounted on a mandrel filling out the coil, whereafter the coil is subjected to a treatment involving radial compression o the winding layers until the wire in each winding becomes deformed by its surface portions at each place being pressed substantially flat against the sur-faces of the ad~oining wire portions o~ the ad~acent windings.
Hereby the windings will be deformed so as to engage each other .in a v~ry compact mannerO The compression of the wlnd-ing layers may be efected by a pùrely mechanical pressure, preferably applied with the coil in a heated condition, but according to the invention it is highly advantageous to e-fect the compression by means of a thermal treatment as described below.
The lnvention also comprlses an apparatus or carry-:lng ou~ the method according to the invention, as defined in th~ app~nd~d claim~0 In the following the invention is described in more detail with reference to the accompanying drawing, in which ~ ig~ l ls a sectional view of a voice coil wound on a mandrel, Fig~ 2 is a corresponding view of the coil at a later stage o the production thereof, FigO 3 is a detailed sectional view of the winding layers o another coil upon deormation thereof,
The invention relates to a method of producing compact electric coils wound of insulated wire of round cross section~
al shape~ and i-t is the purpose of the invention to provide a method whereby an improved space factsr is obtainableO
According to the invention the coil, upon being wound, is maintained or mounted on a mandrel filling out the coil, whereafter the coil is subjected to a treatment involving radial compression o the winding layers until the wire in each winding becomes deformed by its surface portions at each place being pressed substantially flat against the sur-faces of the ad~oining wire portions o~ the ad~acent windings.
Hereby the windings will be deformed so as to engage each other .in a v~ry compact mannerO The compression of the wlnd-ing layers may be efected by a pùrely mechanical pressure, preferably applied with the coil in a heated condition, but according to the invention it is highly advantageous to e-fect the compression by means of a thermal treatment as described below.
The lnvention also comprlses an apparatus or carry-:lng ou~ the method according to the invention, as defined in th~ app~nd~d claim~0 In the following the invention is described in more detail with reference to the accompanying drawing, in which ~ ig~ l ls a sectional view of a voice coil wound on a mandrel, Fig~ 2 is a corresponding view of the coil at a later stage o the production thereof, FigO 3 is a detailed sectional view of the winding layers o another coil upon deormation thereof,
- 3 -~ LS'~96 FigO 4 is a schematic view of a combined coil winding and forming apparatus~
Fig. 5 is a plane view partly in section illustrating alternative mechanical defor~ation of the wires, FigO 6 is a graphic illustration of the thermal treat-ment o the mandrel and the coil, and Fig~ 7 is a similar illustration of the diameter variat-ions of the mandrel and the coil, respectively, during the thermal treatment thereofO
For producing a compact coil according to the invention the coil i5 wound from ordinary round coil wire 2 coated by a }ayer 4 of a suitable insulating and binding material such as polyamid or polyamid-phenol~ The coil is wound on a tubu-lar body 6 of a thin sheet or ~oil material which is placed on a mandrel 8, and as well known the winding may be ef~ected with the mandrel being stationary or rotary. The coil is wound w~th the wlre somewhat prestretched and so as to have each wire portion in one wire layer rested against two wire portions of the adjoining layer.
As mentioned, in order to heat the coil ~or makin~ the binding material 4 run together it is cu~tomary to slmply connect the coil terminals to an electric current source whereb~ h~at :L~ rapidly gen~rated ln the coil windings~ By this heating the windings will expand somewhat, but during not the followi.ng cooling thereo they will~retract themselves against the ~andrel because the binding or bonding material ~olidi:fies to boncl the ~indi~gs before the coil. gets cold~.
According to the invention, however, a di~ferent heat-ing method is used, vizo consisting in supplying heat locally to the mandrel, from which the heat will be trans~erred to the coil windingsO The heat may be supplied to the mandrel
Fig. 5 is a plane view partly in section illustrating alternative mechanical defor~ation of the wires, FigO 6 is a graphic illustration of the thermal treat-ment o the mandrel and the coil, and Fig~ 7 is a similar illustration of the diameter variat-ions of the mandrel and the coil, respectively, during the thermal treatment thereofO
For producing a compact coil according to the invention the coil i5 wound from ordinary round coil wire 2 coated by a }ayer 4 of a suitable insulating and binding material such as polyamid or polyamid-phenol~ The coil is wound on a tubu-lar body 6 of a thin sheet or ~oil material which is placed on a mandrel 8, and as well known the winding may be ef~ected with the mandrel being stationary or rotary. The coil is wound w~th the wlre somewhat prestretched and so as to have each wire portion in one wire layer rested against two wire portions of the adjoining layer.
As mentioned, in order to heat the coil ~or makin~ the binding material 4 run together it is cu~tomary to slmply connect the coil terminals to an electric current source whereb~ h~at :L~ rapidly gen~rated ln the coil windings~ By this heating the windings will expand somewhat, but during not the followi.ng cooling thereo they will~retract themselves against the ~andrel because the binding or bonding material ~olidi:fies to boncl the ~indi~gs before the coil. gets cold~.
According to the invention, however, a di~ferent heat-ing method is used, vizo consisting in supplying heat locally to the mandrel, from which the heat will be trans~erred to the coil windingsO The heat may be supplied to the mandrel
- 4 -` ~O~S7~1~
in any of a variety of manners~ and it is shown by way.of example only that the mandrel may be provided with internal channels 10 for r~ceiving a heating medium from an external sourceO
When the mandrel is heated locally the first result will be a radial expansion of the mandrel itself, whereby the coil wire is generally stretchedO Thereafter the heat is trans- .
ferred to the windings so as to gradually soften the binding material 4 and cause the windings to expand thermally, thus also causing the stretch of the wire to be reducedO When the windings have been heated to the necessary degree for soften-ing the binding material the supply of heat to the mandrel is stopped, whereafter the mandrel will still far some time re-main hot and expandedO
The next and perhaps most lmportant step oE the method according to the invention .is to cool the coil winding from the outside thereo while the mandrel is still expanded, pre-ferably by a positive coo~ing7 eOg~ with a blast of cold air, gas or atomized liquid or by means of cooling claws brought into contact with the exterior coil sur~aceO This cooling causes th~ coil winding to crimp, and since the mandrel ls still expan~ed the crlmping o the wire results in the build-ing up o~ a consiclerable stretch 1~ the wir~ ancl correspond-ingly a cons:Lderable ~nwardly directed pressing force of an outer winding layer against an inner winding layer and fur-ther against the surface o~ the mandrel through the sheet 60 The forces pro~uced hereby are strong enough to cause the single wire portions to be pressure deformed by their engage-ment with the adjoining portions, and as illustrated in figO
2 the result is that the juxtapposed wire portions will get deformed into a honey comb cross sectional shape so as to be :' - 16)45796 rested against each other in a practically plane surface-to-surface-relationship rather than a tangential engagement between round wires. This involves that an optimal space fac-tor is obtained and that also the bonding between the juxt-apposed wlre surface portions becomes optimalO It should be mentioned that the wire is able to withstand a considerable stretching force due to the overall frictional engagement be-tween the juxtapposed wire portionsO
When thereafter also the mandrel is cooled the associated contraction thereof will make the coLl structure easily re-leasable from the mandrel, since at that time the coil has already been stabilized in its deformed shape~ If desired, for further reducing the maximum thickness of the coil wind-ing the outer surface of the coil may be ground for removing any surplus oE bonding materialO
The honey comb structure will be still more expressed in a coil having three or more winding layers, as illustrated in fig. 3 whlch shows a raction of a four layer coil made `according to the inventionO Besides, this coil has been wound direct on the mandrel without the use o a tubular body 6.
: The mandrel may be cooled naturally or by means of a cooling medium applied to the exterior or interior of the mandrel, and upon the removal of the coil therefrom the man-drel ma~ rec~i~e a new coil member to be treated, with the mandrel us~d ~ith~r a~ a winding mandrel or as a mandrQ1 for receiving an already wound coil memberO
Generall~ the important eature o the invention is the crimping of the coil windings a~ainst a mandrel or core mem-ber which in the heated condition of the coil fills out the space inside the coil and maintains its diameter while the crimping o the windings is going on. Thus, it is not essen-_ ~ _ tial, though highly advantageous that the mandrel should besubjected to a positive heating9 since it could alternatively be mechanically expanded and contractedO The deformation caused by the cooling crimping of the coil is not primarily dependent of the coil previously having been heated to any particular temperature9 hut by the said preheating up to e~gO
300C it is obtained that the bonding material ~ flows to-gether and th t the subsequent crimping deformation of the wire is facilitatedO Due to the high crimping force, however, the wire would get deformed even without being particularly hotO
Principally the coil may be removed rom the mandrel without the latter -Eirst being contracted, since the crimped coil could be reheated for expansion without the deormed wire cross section being redeEormed into the orlginal round shap~J Moreover~ the wire deEormation principally could be efEected mechanically by forcing clamp jaws against the coil or by expanding the mandrel with the coil supported inside a surrounding cylindric element, preferably while the coil is heated, or by treating the coil with a pressing roller moved along the int~rior or exterior side o:F the coil~
As mentlorlc~cl the invent:Lon also comprises an apparatus ~or eE~ect~rlcJ ~h~ coll cle~ormation accord:lng to th~ prlnciples described hereinbeforeO The apparatus may be combined with a winding mach.ine so as to automatically receive on its mandrel or mandr~ls the coil members wound by the windlng machine, or the apparatus may be integral with the winding machine, the expansion mandrels thereoE being used additionally as winding mandr~ls~ whether being of the stationary or the rotary typeO
The mandrels may be arranged in a row on a movable support such as a turn table7 which is designated 12 in fig~ l, and which moves the mandrels successively past a receiving stat-ion in which they receive the coil members eith~r as wound onto the mandrels or supplied thereto from an independent winding machine, and further to a heating station in which -~
the mandrels are heated eOg. by means of hot oil or air sup-plied to the interior channel system 10 through holes or slots 14 in a glider body 16 engaging the support 12. ~or the invention, however, it is entirely unimportant how the heating is effected, because also the coil is allowed to be heated, i.e. the heating could well be effected from the outside of the mandrel, e.g. by means of a high frequency heating technique.
Thereafter the support 12 is moved further to or past a coil cooling station in which suitable means are provided for cooling the coils from the outside thereof, e.g. simply by a blast of cold air or gas or atomized water whereby the said defoxmation of the coil wire will take place. The next station is a reject station in which the coils are removed from the mandrels upon these in the meantime having been ~ cooled either by natural cooling or by means of a cooling medium supplied to the internal channel system L or in any other manner. From this latter station the mandrels are moved back to the initial receiving station. Alternatively the appa-ratus may be provided with means for a mechanically controlled expansion and contraction of the mandrels or with the above mentioned means for mechanically pressing the coil members.
It should be mentioned that coils wound of aluminium or soft coppar wire are particularly well suited to be treated in the described manner and that the invention eliminates or reduces the normal problem of the coil thickness being locally increased at the crossing areas where the wire ~rom one wind-~045796 ing crosses the top of an underlying wire for passing to thenext winding9 this problem being due to the fact that the winding layers are wound with alternating pitch; at the said crossing areas the wire will be deformed into a flat shape by the crimping of the coil whereby the said local increase of the thickness will disappearn In figO 3 such.a wire cros-sing is illustrated with the wire W as the central wire in the crossing area shownO
The invention is usable also for the production of coils of non-circular shape, but normally it should be preferred to first wind and treat a round coil which is pressed into its desired shape a~ter having been crimped and removed from the mandrelO
The invention also comprises a coil produced by the de-scribed method so as to have an improved space factorO For some coils the space factor itself is not important, but it is very important that an associated advantage is a very firm bonding of the coil windings to each other and to the bobbin~
if any, whereby a very rigid coil is obtained, and that the heat conductivety of the coil will be very goodO
By way of example an apparatus according to the invention is schematically illustrated in figO 40 It comprises a turn table 20 having a number of radially protruding mandrels 22 and gear means (not shown~ for turning the table stepwise, whereby the mandrels are successively brought to rest in the various stations of the apparatusO A first station is a wind-ing station in which a well known winding device 24 operates to wind a coil 25 on the mandrel, the mandrel thereafter being moved stepwise through three positions constituting a heating stationO In each of these positions is placed a heater unit 26,28 and 30, respectively7 each having a heated rod member _ g _ . .
~L~9L5'7~
32 which is reciprocally arran~ed so as to be shiftable be-tween an active position in which it projects into an outer cylindric cavity 34 of the mandrel 22 so as to heat the man~
drel from the inside thereof, and a retracted, inoperative position in which it allows the turn table to be rotatedO
The elements 32 miyht as well represent the exhaust spouts o~ air heater units.
The coil winding device 24 leaves the wire uncut between the coils wound on the consecutive mandrels, so the wire, as shown at 369 will extend stretched between the consecutive coils in the said heating station9 whereby there are no pro-blems as to anchoring of loose wire ends of the coilsD B~
the heating the mandrels 22 expand and trans~er heat to the coils 25 whereb~ the coating on the coil wire is soEtenedO
In the next station, designated 38, the coil is sub~ected to a blast of cold alr produced b~ a blower ~0 and directed towards the outside o~ the coil by sultably arranged outlet openings 42 o~ an air duct system ~4~ ~ereby the coil 25 or at least the outer surface thereof is almost immediately cooled down to below the softening or melting point of the bonding coating on the wire and the coil starts crimping while the mandr~l is still hot~ Also in the next position, designated 4G the coil .i.5 subjected to the cooling air where-b~ its cr:Lmpin~ :Ls compl~ted acJalnst the mandrel which is still e~panfled though its temperature has decreased somewhat from its maximumO Between the positions 38 and 46 is provided a cutting clevice ~8 whi.ch is actuable to cut the exposed wlre portion 36 which is now bonded t~ the respective coils at the places where it leaves the coilO
Also in the ~ollowing position, designated 50, the cool-ing blast is directed against the mandrel and the coil, and ~ ~ `
rejector means ~not shown, but well known in the art) are pro-vided for removing the coil from the mandrel~ In the meantime the mandrel has cooled down sufficiently to contract itself to such a degree that the coil is readily releasable there-fromO
In the following position, designated 52, the mandrel is further cooled, if necessary, before it is moved~further to the winding station. If applicable the tubular core 6 or a similar bobbin may be placed on the mandrel in the position ; 10 52 if not in the winding station itselfO
As mentioned? the winding station may be substituted by a station in which ready wound coil members are mounted on the mandrels 22. Further, as mentioned, the means for effect-ing the pressing of the coils may be substituted partly or entirely by mechanical pressing means, an example of such an arrangement being shown in fig. 5. An expansible mandrel 60 is made of two or more segments 62 having cylindric exterior .
~ ~ ~ surface portions and conical interior surface portions cooper-:
~ ating with a conical end portion 64 of a rod 66 which is oper-: :
20~ ~ able, by control means not shown, to be forced into the inte-rior;space of the split mandrel 60 so as to cause the segments thereof to expand. The mandrel is rested on a base plate 68 and is Lntroduceable into a cylindric member 70 together with ., .
a coil member 72 mounted on the mandrelO When the mandrel is expanded by means of the rod 66 the coil will be pressed be-tween the mandrel and the inner side of the cylindric member 70, and thereafter, upon contraction of the mandrel, the coil is rejectable from the cylindric member by means of the base plate 68 being pushed through the cylindric member.
The cylindric member 70 may be segmented and have each of its segments operatively connected with means such as hy-..;, ,.. ,. , . , ,. , , . , :
~4~i796 draulic cylinders 74 for moving the se~ments radially whereby a positive pressin~ ~orce may be applied additionally or alter--nativel~ against the exterior side of the coilO
The mandrel 60 may be representative of the mechanically expansible mandrel which is mentioned hereinbefore in connect-ion with the described cooling crimping of the coil member) and both the mandrel 60 and the se~mented cylindric ~ember 70 may be representative of the above mentioned mechanical cool-ing claw means for effecting the crimping cooling o~ the heated coil memberO
Though the desired deformation of the coil wire is thus effectable by mechanical means the described thermally effected deformation will normally be highly preferableO The interre-lated ~igsO 6 and 7 show the variation of the mandrel dlameter ~igO 6, solid li.ne) an~ the coil diameter ~figO 6, dotted line) a9 a ~unction o~ the tlme during which th~ described heating and cooling i9 going on~ until the coil is removed from the mandrel at the moment tR~ and figO 7 correspondingly shows the temperature variation of the mandrel (solid line) and the coil ~dotted line)O In figO 7 the temperature TM re-presents the melting point of the bonding material on -the coil w:i.reO rl!his material starts to solldify when the coil tem-peratur~ at the moment tl, drops below ~M~ ~nd a short t.ime therca:~k~r~ at tlte ~noment t~, the mate.rial has s~t su~ici~nt~
ly to therea~ter maintain the coil diameter substantially constant wh:ile thc mandrel is still shrinking by the ~urther coollncJ thereo~a In view o~ the ~oregoing detailed descr~ption of the heating/cooling cycle~ however, it is not deemed neces sary to explain the curves of ~igsO 6 and 7 in more detailO
in any of a variety of manners~ and it is shown by way.of example only that the mandrel may be provided with internal channels 10 for r~ceiving a heating medium from an external sourceO
When the mandrel is heated locally the first result will be a radial expansion of the mandrel itself, whereby the coil wire is generally stretchedO Thereafter the heat is trans- .
ferred to the windings so as to gradually soften the binding material 4 and cause the windings to expand thermally, thus also causing the stretch of the wire to be reducedO When the windings have been heated to the necessary degree for soften-ing the binding material the supply of heat to the mandrel is stopped, whereafter the mandrel will still far some time re-main hot and expandedO
The next and perhaps most lmportant step oE the method according to the invention .is to cool the coil winding from the outside thereo while the mandrel is still expanded, pre-ferably by a positive coo~ing7 eOg~ with a blast of cold air, gas or atomized liquid or by means of cooling claws brought into contact with the exterior coil sur~aceO This cooling causes th~ coil winding to crimp, and since the mandrel ls still expan~ed the crlmping o the wire results in the build-ing up o~ a consiclerable stretch 1~ the wir~ ancl correspond-ingly a cons:Lderable ~nwardly directed pressing force of an outer winding layer against an inner winding layer and fur-ther against the surface o~ the mandrel through the sheet 60 The forces pro~uced hereby are strong enough to cause the single wire portions to be pressure deformed by their engage-ment with the adjoining portions, and as illustrated in figO
2 the result is that the juxtapposed wire portions will get deformed into a honey comb cross sectional shape so as to be :' - 16)45796 rested against each other in a practically plane surface-to-surface-relationship rather than a tangential engagement between round wires. This involves that an optimal space fac-tor is obtained and that also the bonding between the juxt-apposed wlre surface portions becomes optimalO It should be mentioned that the wire is able to withstand a considerable stretching force due to the overall frictional engagement be-tween the juxtapposed wire portionsO
When thereafter also the mandrel is cooled the associated contraction thereof will make the coLl structure easily re-leasable from the mandrel, since at that time the coil has already been stabilized in its deformed shape~ If desired, for further reducing the maximum thickness of the coil wind-ing the outer surface of the coil may be ground for removing any surplus oE bonding materialO
The honey comb structure will be still more expressed in a coil having three or more winding layers, as illustrated in fig. 3 whlch shows a raction of a four layer coil made `according to the inventionO Besides, this coil has been wound direct on the mandrel without the use o a tubular body 6.
: The mandrel may be cooled naturally or by means of a cooling medium applied to the exterior or interior of the mandrel, and upon the removal of the coil therefrom the man-drel ma~ rec~i~e a new coil member to be treated, with the mandrel us~d ~ith~r a~ a winding mandrel or as a mandrQ1 for receiving an already wound coil memberO
Generall~ the important eature o the invention is the crimping of the coil windings a~ainst a mandrel or core mem-ber which in the heated condition of the coil fills out the space inside the coil and maintains its diameter while the crimping o the windings is going on. Thus, it is not essen-_ ~ _ tial, though highly advantageous that the mandrel should besubjected to a positive heating9 since it could alternatively be mechanically expanded and contractedO The deformation caused by the cooling crimping of the coil is not primarily dependent of the coil previously having been heated to any particular temperature9 hut by the said preheating up to e~gO
300C it is obtained that the bonding material ~ flows to-gether and th t the subsequent crimping deformation of the wire is facilitatedO Due to the high crimping force, however, the wire would get deformed even without being particularly hotO
Principally the coil may be removed rom the mandrel without the latter -Eirst being contracted, since the crimped coil could be reheated for expansion without the deormed wire cross section being redeEormed into the orlginal round shap~J Moreover~ the wire deEormation principally could be efEected mechanically by forcing clamp jaws against the coil or by expanding the mandrel with the coil supported inside a surrounding cylindric element, preferably while the coil is heated, or by treating the coil with a pressing roller moved along the int~rior or exterior side o:F the coil~
As mentlorlc~cl the invent:Lon also comprises an apparatus ~or eE~ect~rlcJ ~h~ coll cle~ormation accord:lng to th~ prlnciples described hereinbeforeO The apparatus may be combined with a winding mach.ine so as to automatically receive on its mandrel or mandr~ls the coil members wound by the windlng machine, or the apparatus may be integral with the winding machine, the expansion mandrels thereoE being used additionally as winding mandr~ls~ whether being of the stationary or the rotary typeO
The mandrels may be arranged in a row on a movable support such as a turn table7 which is designated 12 in fig~ l, and which moves the mandrels successively past a receiving stat-ion in which they receive the coil members eith~r as wound onto the mandrels or supplied thereto from an independent winding machine, and further to a heating station in which -~
the mandrels are heated eOg. by means of hot oil or air sup-plied to the interior channel system 10 through holes or slots 14 in a glider body 16 engaging the support 12. ~or the invention, however, it is entirely unimportant how the heating is effected, because also the coil is allowed to be heated, i.e. the heating could well be effected from the outside of the mandrel, e.g. by means of a high frequency heating technique.
Thereafter the support 12 is moved further to or past a coil cooling station in which suitable means are provided for cooling the coils from the outside thereof, e.g. simply by a blast of cold air or gas or atomized water whereby the said defoxmation of the coil wire will take place. The next station is a reject station in which the coils are removed from the mandrels upon these in the meantime having been ~ cooled either by natural cooling or by means of a cooling medium supplied to the internal channel system L or in any other manner. From this latter station the mandrels are moved back to the initial receiving station. Alternatively the appa-ratus may be provided with means for a mechanically controlled expansion and contraction of the mandrels or with the above mentioned means for mechanically pressing the coil members.
It should be mentioned that coils wound of aluminium or soft coppar wire are particularly well suited to be treated in the described manner and that the invention eliminates or reduces the normal problem of the coil thickness being locally increased at the crossing areas where the wire ~rom one wind-~045796 ing crosses the top of an underlying wire for passing to thenext winding9 this problem being due to the fact that the winding layers are wound with alternating pitch; at the said crossing areas the wire will be deformed into a flat shape by the crimping of the coil whereby the said local increase of the thickness will disappearn In figO 3 such.a wire cros-sing is illustrated with the wire W as the central wire in the crossing area shownO
The invention is usable also for the production of coils of non-circular shape, but normally it should be preferred to first wind and treat a round coil which is pressed into its desired shape a~ter having been crimped and removed from the mandrelO
The invention also comprises a coil produced by the de-scribed method so as to have an improved space factorO For some coils the space factor itself is not important, but it is very important that an associated advantage is a very firm bonding of the coil windings to each other and to the bobbin~
if any, whereby a very rigid coil is obtained, and that the heat conductivety of the coil will be very goodO
By way of example an apparatus according to the invention is schematically illustrated in figO 40 It comprises a turn table 20 having a number of radially protruding mandrels 22 and gear means (not shown~ for turning the table stepwise, whereby the mandrels are successively brought to rest in the various stations of the apparatusO A first station is a wind-ing station in which a well known winding device 24 operates to wind a coil 25 on the mandrel, the mandrel thereafter being moved stepwise through three positions constituting a heating stationO In each of these positions is placed a heater unit 26,28 and 30, respectively7 each having a heated rod member _ g _ . .
~L~9L5'7~
32 which is reciprocally arran~ed so as to be shiftable be-tween an active position in which it projects into an outer cylindric cavity 34 of the mandrel 22 so as to heat the man~
drel from the inside thereof, and a retracted, inoperative position in which it allows the turn table to be rotatedO
The elements 32 miyht as well represent the exhaust spouts o~ air heater units.
The coil winding device 24 leaves the wire uncut between the coils wound on the consecutive mandrels, so the wire, as shown at 369 will extend stretched between the consecutive coils in the said heating station9 whereby there are no pro-blems as to anchoring of loose wire ends of the coilsD B~
the heating the mandrels 22 expand and trans~er heat to the coils 25 whereb~ the coating on the coil wire is soEtenedO
In the next station, designated 38, the coil is sub~ected to a blast of cold alr produced b~ a blower ~0 and directed towards the outside o~ the coil by sultably arranged outlet openings 42 o~ an air duct system ~4~ ~ereby the coil 25 or at least the outer surface thereof is almost immediately cooled down to below the softening or melting point of the bonding coating on the wire and the coil starts crimping while the mandr~l is still hot~ Also in the next position, designated 4G the coil .i.5 subjected to the cooling air where-b~ its cr:Lmpin~ :Ls compl~ted acJalnst the mandrel which is still e~panfled though its temperature has decreased somewhat from its maximumO Between the positions 38 and 46 is provided a cutting clevice ~8 whi.ch is actuable to cut the exposed wlre portion 36 which is now bonded t~ the respective coils at the places where it leaves the coilO
Also in the ~ollowing position, designated 50, the cool-ing blast is directed against the mandrel and the coil, and ~ ~ `
rejector means ~not shown, but well known in the art) are pro-vided for removing the coil from the mandrel~ In the meantime the mandrel has cooled down sufficiently to contract itself to such a degree that the coil is readily releasable there-fromO
In the following position, designated 52, the mandrel is further cooled, if necessary, before it is moved~further to the winding station. If applicable the tubular core 6 or a similar bobbin may be placed on the mandrel in the position ; 10 52 if not in the winding station itselfO
As mentioned? the winding station may be substituted by a station in which ready wound coil members are mounted on the mandrels 22. Further, as mentioned, the means for effect-ing the pressing of the coils may be substituted partly or entirely by mechanical pressing means, an example of such an arrangement being shown in fig. 5. An expansible mandrel 60 is made of two or more segments 62 having cylindric exterior .
~ ~ ~ surface portions and conical interior surface portions cooper-:
~ ating with a conical end portion 64 of a rod 66 which is oper-: :
20~ ~ able, by control means not shown, to be forced into the inte-rior;space of the split mandrel 60 so as to cause the segments thereof to expand. The mandrel is rested on a base plate 68 and is Lntroduceable into a cylindric member 70 together with ., .
a coil member 72 mounted on the mandrelO When the mandrel is expanded by means of the rod 66 the coil will be pressed be-tween the mandrel and the inner side of the cylindric member 70, and thereafter, upon contraction of the mandrel, the coil is rejectable from the cylindric member by means of the base plate 68 being pushed through the cylindric member.
The cylindric member 70 may be segmented and have each of its segments operatively connected with means such as hy-..;, ,.. ,. , . , ,. , , . , :
~4~i796 draulic cylinders 74 for moving the se~ments radially whereby a positive pressin~ ~orce may be applied additionally or alter--nativel~ against the exterior side of the coilO
The mandrel 60 may be representative of the mechanically expansible mandrel which is mentioned hereinbefore in connect-ion with the described cooling crimping of the coil member) and both the mandrel 60 and the se~mented cylindric ~ember 70 may be representative of the above mentioned mechanical cool-ing claw means for effecting the crimping cooling o~ the heated coil memberO
Though the desired deformation of the coil wire is thus effectable by mechanical means the described thermally effected deformation will normally be highly preferableO The interre-lated ~igsO 6 and 7 show the variation of the mandrel dlameter ~igO 6, solid li.ne) an~ the coil diameter ~figO 6, dotted line) a9 a ~unction o~ the tlme during which th~ described heating and cooling i9 going on~ until the coil is removed from the mandrel at the moment tR~ and figO 7 correspondingly shows the temperature variation of the mandrel (solid line) and the coil ~dotted line)O In figO 7 the temperature TM re-presents the melting point of the bonding material on -the coil w:i.reO rl!his material starts to solldify when the coil tem-peratur~ at the moment tl, drops below ~M~ ~nd a short t.ime therca:~k~r~ at tlte ~noment t~, the mate.rial has s~t su~ici~nt~
ly to therea~ter maintain the coil diameter substantially constant wh:ile thc mandrel is still shrinking by the ~urther coollncJ thereo~a In view o~ the ~oregoing detailed descr~ption of the heating/cooling cycle~ however, it is not deemed neces sary to explain the curves of ~igsO 6 and 7 in more detailO
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of compacting an electric coil to increase the space factor thereof, the coil being comprised of a plurality of turns of round cross-sectional wires arranged in layers, the method comprising the steps of, arranging a coil on a mandrel filling out the coil, subjecting the mandrel and coil to a differential thermal treatment to effectively cause the coil windings to be tightened about the mandrel to such a degree that the resulting radial forces on the wire of the coil are sufficient to effect a cross-sectional deformation of the wire in each of the turns against adjacent turns and therewith compaction of the windings.
2. A method according to claim 1, characterized in that the step of subjecting the mandrel and coil to a differential thermal treatment includes heating the mandrel to cause a pre-determined expansion thereof, cooling the coil with the mandrel still expanded, and contracting the mandrel for releasing the coil.
3. A method according to claim 2, characterized in that the step of contracting the mandrel includes directing a cooling medium at the mandrel.
4. A method according to claim 2, characterized in that the coil wire is insulated with a thermo-softenable insulation material, and in that the mandrel is heated to a temperature sufficient to soften the insulation material.
5. A method according to claim 4, characterized in that the step of heating the mandrel includes heating the mandrel from the inside thereof and allowing a transfer of heat from the mandrel to the coil, and wherein the step of cooling the coil includes supplying a cooling medium to the outside of the coil.
6. An apparatus for producing compact electric coils having a high space factor, comprising a plurality of mandrels mounted in a row on support means adapted to successively move the mandrels past a receiving station in which the coils are wound or placed on the mandrels, a heating station in which the mandrels are caused to expand by heating, a coil cooling station in which the coils are cooled from the outside thereof, and a delivery station in which the coils are removed from the mandrels upon cooling of the mandrels.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB26221/74A GB1514458A (en) | 1974-06-13 | 1974-06-13 | Method and an apparatus for producing compact electric coils |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1045796A true CA1045796A (en) | 1979-01-09 |
Family
ID=10240241
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA229,242A Expired CA1045796A (en) | 1974-06-13 | 1975-06-12 | Manufacture of compacted coils |
Country Status (17)
| Country | Link |
|---|---|
| JP (1) | JPS5133618A (en) |
| AT (1) | AT344267B (en) |
| AU (1) | AU8202475A (en) |
| BE (1) | BE830195A (en) |
| CA (1) | CA1045796A (en) |
| CH (1) | CH607269A5 (en) |
| DE (1) | DE2525466A1 (en) |
| DK (1) | DK148571C (en) |
| ES (1) | ES438775A1 (en) |
| FI (1) | FI751763A (en) |
| FR (1) | FR2275008A1 (en) |
| GB (1) | GB1514458A (en) |
| IE (1) | IE41086B1 (en) |
| IT (1) | IT1038952B (en) |
| NL (1) | NL7506928A (en) |
| NO (1) | NO141106C (en) |
| SE (1) | SE408504B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9614423B2 (en) | 2012-04-07 | 2017-04-04 | Traugott Weller | Method for producing rotating electrical machines |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53129327U (en) * | 1977-03-18 | 1978-10-14 | ||
| JPS53142603A (en) * | 1977-05-18 | 1978-12-12 | Matsushita Electric Works Ltd | Rotor coil-tube coreless-motor |
| JPS60176555A (en) * | 1984-02-23 | 1985-09-10 | Ueno Seiyaku Kk | Preservation of chinese noodle |
-
1974
- 1974-06-13 GB GB26221/74A patent/GB1514458A/en not_active Expired
-
1975
- 1975-05-13 FI FI751763*A patent/FI751763A/fi not_active Application Discontinuation
- 1975-06-07 DE DE19752525466 patent/DE2525466A1/en not_active Withdrawn
- 1975-06-09 IE IE1294/75A patent/IE41086B1/en unknown
- 1975-06-10 NO NO752051A patent/NO141106C/en unknown
- 1975-06-10 DK DK259275A patent/DK148571C/en not_active IP Right Cessation
- 1975-06-11 IT IT7524274A patent/IT1038952B/en active
- 1975-06-11 NL NL7506928A patent/NL7506928A/en not_active Application Discontinuation
- 1975-06-11 AU AU82024/75A patent/AU8202475A/en not_active Expired
- 1975-06-11 CH CH752275A patent/CH607269A5/xx not_active IP Right Cessation
- 1975-06-11 AT AT444975A patent/AT344267B/en not_active IP Right Cessation
- 1975-06-12 JP JP50072825A patent/JPS5133618A/en active Pending
- 1975-06-12 SE SE7506771A patent/SE408504B/en unknown
- 1975-06-12 CA CA229,242A patent/CA1045796A/en not_active Expired
- 1975-06-12 FR FR7518399A patent/FR2275008A1/en not_active Withdrawn
- 1975-06-13 BE BE2054399A patent/BE830195A/en unknown
- 1975-06-13 ES ES438775A patent/ES438775A1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9614423B2 (en) | 2012-04-07 | 2017-04-04 | Traugott Weller | Method for producing rotating electrical machines |
Also Published As
| Publication number | Publication date |
|---|---|
| NO752051L (en) | 1975-12-16 |
| IE41086L (en) | 1975-12-13 |
| NO141106C (en) | 1980-01-09 |
| DK148571B (en) | 1985-08-05 |
| DE2525466A1 (en) | 1976-01-02 |
| ES438775A1 (en) | 1977-03-16 |
| JPS5133618A (en) | 1976-03-22 |
| IT1038952B (en) | 1979-11-30 |
| AU8202475A (en) | 1976-12-16 |
| SE408504B (en) | 1979-06-11 |
| SE7506771L (en) | 1975-12-15 |
| ATA444975A (en) | 1977-11-15 |
| DK148571C (en) | 1985-12-30 |
| AT344267B (en) | 1978-07-10 |
| CH607269A5 (en) | 1978-11-30 |
| DK259275A (en) | 1975-12-14 |
| GB1514458A (en) | 1978-06-14 |
| NO141106B (en) | 1979-10-01 |
| NL7506928A (en) | 1975-12-16 |
| BE830195A (en) | 1975-10-01 |
| IE41086B1 (en) | 1979-10-10 |
| FI751763A (en) | 1975-12-14 |
| FR2275008A1 (en) | 1976-01-09 |
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