Abstract
The invention relates to a method for producing stranded wires, including the steps of applying an insulation layer to lines, separating the insulated lines, individually removing the insulation layer from the separated lines along a partial length of the lines, and bringing the lines together to form a stranded wire, wherein the partial lengths are arranged at the same level at least in sections for the purpose of forming a non-insulated contact region.
Claims
1.-17. (canceled)
18. A method for producing stranded wires, comprising: applying an insulation layer to lines to produce insulated lines; separating the insulated lines; removing the insulation layer from the separated lines along a partial length of the insulated lines; and bringing the lines together to form a stranded wire, wherein the partial lengths are arranged to form a non-insulated contact region.
19. The method of claim 18 wherein the method takes place continuously.
20. The method of claim 18 wherein at least said removing and said bringing steps take place batchwise.
21. The method of claim 18 wherein said removal step comprises laser ablation of the insulation layer.
22. The method of claim 18 wherein the lines are arranged laterally spaced apart from one another during said removing step.
23. The method of claim 18 wherein different-length, non-insulated partial lengths of the lines are formed during said removing step.
24. The method of claim 18 wherein equal-length, non-insulated partial lengths of the lines, said partial lengths arranged in an offset manner, are formed during the removing step.
25. The method of claim 18 wherein different-length, non-insulated partial lengths of the lines are formed based on different transportation speeds of the lines during said removing step.
26. The method of claim 18 wherein said bringing the lines together comprises stranding the lines.
27. The method of claim 18 wherein said bringing the lines together further comprises compression molding to form a shaped stranded wire.
28. The method of claim 18 wherein ends of the non-insulated partial lengths that are disposed at a rear in a transportation direction of the lines are arranged flush when the lines are brought together in accordance with said bringing step.
29. The method of claim 18 wherein ends of the non-insulated partial lengths that are disposed at a front in a transportation direction of the lines are arranged flush when the lines are brought together in accordance with said bringing step.
30. The method of claim 29 wherein the ends of the non-insulated partial lengths that are at the front in the transportation direction of the lines form a start of a new stranded wire.
31. The method of claim 18 wherein the lines comprises a plurality of individual wires and/or partial stranded wires.
32. An apparatus for producing stranded wires, comprising: a device configured to apply an insulation layer to lines; a device configured to bring the lines together to form a stranded wire; and a device configured to remove the insulation layer from the lines along a partial length of the lines; and a device configured to separate the insulated lines arranged upstream of the device configured to remove the insulation layer, wherein the device configured to remove the insulation layer has means for individually removing the insulation layer from the separated lines along a partial length of the lines, wherein the device configured to bring the lines together and the device configured to remove the insulation layer interact such that the partial lengths of the lines are arranged at the same position at least in sections to form a non-insulated contact region.
33. A stranded wire, comprising: lines which each have an insulation layer and are each non-insulated over a partial length thereof; wherein the non-insulated partial lengths form a contact region at which the lines are electrically conductively connected to one another; and wherein the insulation layer is removed along the partial lengths individually for each individual wire before the lines are joined to form a stranded wire.
34. An electric machine, comprising: magnetic components having a large number of lines in receiving openings of a rotor and/or stator; said lines each having an insulation layer and are each non-insulated over a partial length thereof; wherein the non-insulated partial lengths form a contact region at which the lines are electrically conductively connected to one another; and wherein the insulation layer is removed along the partial lengths individually for each individual wire before the lines are joined to form a stranded wire.
Description
[0079] The invention will be explained in more detail below with reference to exemplary embodiments together with further details with reference to the appended drawings,
[0080] in which:
[0081] FIG. 1 schematically shows a litz wire with three layers 1, 2, 3 composed of individual wires which are twisted with respect to one another;
[0082] FIG. 2 schematically shows a stranded wire or a litz wire which is constructed from partial stranded wires. The litz wires or partial stranded wires can have different directions of twist, as indicated here. The litz wires or partial stranded wires can in turn be twisted with one another;
[0083] FIG. 3 schematically shows front and plan views of a shaped stranded wire with electrically and mechanically contact-connected head regions with a sleeve (lower illustration) and without a sleeve (upper illustration);
[0084] FIG. 4a schematically shows a front view of a stator of an electric motor with shaped stranded wires which are inserted by way of example. The shaped stranded wires are not rectangular here, but rather trapezoidal. There are two shaped stranded wires in each slot. In order to simplify the interconnection to form windings, in particular for divided windings, the shaped stranded wires can be of different lengths;
[0085] FIG. 4b schematically shows a plan view of the stator according to FIG. 4a;
[0086] FIG. 5a schematically shows a shaped stranded wire in which a wire makes four complete revolutions, that is to say 4 lays. The triangles indicate the lays. The depicted lengths are the active length (part of the shaped stranded wire within the stator slot), the lay length and the half-lay length;
[0087] FIG. 5b schematically shows a plan view of a wire of a shaped stranded wire which has to cover a rectangular path for one lay, which rectangular path corresponds to the circumference of the shaped stranded wire. Accordingly, half the path has to be covered for half a lay;
[0088] FIG. 5c schematically shows the difference in length which is produced between the direct path (for example a core wire) and the individual wire which has half a lay. Horizontal: length of the direct path; vertical: diversion for a half-lay; connecting line: resulting length. The perpendicular from the direct path to the resulting length indicates the difference in length;
[0089] FIG. 6a schematically shows an exemplary embodiment in which individual wires or partial stranded wires, that is to say in general lines, of different length are produced (for the various layers 1, 2, 3 according to FIG. 1) and these are each stripped of insulation by the same length at the ends. In the event of twisting, these lines should ideally terminate flush, so that both the start and also the end of the regions which are stripped of insulation come to lie one above the other for all lines;
[0090] FIG. 6b schematically shows a further exemplary embodiment in which all of the individual wires or partial stranded wires, that is to say in general lines, are cut to the same length but have insulation-stripped regions of different sizes. In the event of twisting, the starting edges of the region which is stripped of insulation will come to lie flush one above the other, but the ends of the wires will not terminate flush with one another, so that additional cutting is necessary here and waste is produced;
[0091] FIG. 7 schematically shows an individual wire production line in which the (future) enameled wire runs through an insulation bath, the applied enamel is dried by a drying device, then partially stripped of insulation and then trimmed to length. Different lengths for the individual wires which are to be cut to length are illustrated by way of example here (layers 1, 2, 3, cf. FIG. 1);
[0092] FIG. 8a schematically shows an exemplary embodiment of an insulation-stripping apparatus for batchwise production in a variant with litz wires which are trimmed to the correct end length (=FIG. 6a);
[0093] FIG. 8b schematically shows a further insulation-stripping apparatus for batchwise production in a variant with insulation-stripped regions of different length (=FIG. 6b);
[0094] FIG. 9a schematically shows an exemplary embodiment of a production variant with continuous production with insulation-stripped regions of different length (indicated for a three-layer stranded wire here) which are twisted, roll forged and then trimmed to length;
[0095] FIG. 9b schematically shows a variant of the exemplary embodiment according to FIG. 9a in which insulation-stripped regions of equal length are placed such that they come to lie flush one above the other in the event of twisting;
[0096] FIG. 10 schematically shows a further exemplary embodiment of a production variant for a shaped stranded wire which is composed of partial stranded wires, in which three partial stranded wires are shown in a manner representing the further partial stranded wires of the shaped stranded wire;
[0097] FIG. 11 shows a possible order of the production steps of a continuous shaped stranded wire production method for example according to FIGS. 9a and 9b;
[0098] FIG. 12 shows a possible order of the production steps of a batchwise shaped stranded wire production method for example according to FIGS. 8a and 8b.
[0099] The product which is produced using the method according to the invention, that is to say the stranded wire or the shaped stranded wire and also an electric machine having a stranded wire of this kind, are illustrated in FIGS. 1 to 6. Exemplary embodiments according to the invention of the production method and also the apparatus for producing the stranded wire are shown in FIGS. 7 to 12. The stranded wire and, respectively, the electric machine having the stranded wire are disclosed and claimed as such.
[0100] The stranded wire 10 according to FIG. 1 may be a complete stranded wire which is constructed from a plurality of lines, that is to say from a plurality of individual wires 12, which are each insulated. FIG. 1 can also serve as an example of a partial stranded wire 18 which is a constituent part of a larger, superordinate complete stranded wire 10. The partial stranded wire 18 is likewise constructed from individual wires 12. The direction of twist of the individual wires 12 is indicated, by way of example, by the arrow running in the clockwise direction. The stranded wire 10 or the partial stranded wire 18 is constructed from a plurality of layers 20, 21, 22 of individual wires 12 which are provided with different hatching for reasons of illustration. The innermost layer 20, also called layer 1, is formed by a so-called core wire. The layer 21 which is second here is arranged around the core wire and is formed from 6 individual wires 12 in the example according to FIG. 1. The third layer 22 is arranged around the second layer 21 and is likewise formed by individual wires 12, specifically by 12 individual wires 12. A different number of layers is possible, as is a different number of individual wires 12 per layer.
[0101] A stranded wire 10 comprising a plurality of partial stranded wires 18 is shown in FIG. 2. The partial stranded wires 18 can be twisted in opposite directions. The entire stranded wire 10 is in turn twisted in one direction, so that multiple twisting of the individual wires 12 and, respectively, of the partial stranded wires 18 is produced overall.
[0102] FIG. 3 shows the entire stranded wire 10 with the head-side contact regions 15 at the two ends of the stranded wire 10. In the contact region 15, the individual wires 12 and/or the partial stranded wires 18 are electrically and mechanically connected to one another by suitable means and methods. As is clear from the front views according to FIG. 3, the contact regions 15 are compressed to form a rectangular cross section. Other cross-sectional shapes are possible. In the example according to FIG. 3, the stranded wire 10 is compressed at both longitudinal ends and, respectively, has contact regions 15 there. It is also possible to compress the stranded wire 10 only at one of the two longitudinal ends. The upper illustration shows the stranded wire 10 without a sleeve. The lower illustration according to FIG. 3 shows the stranded wire 10 with a sleeve which is pushed over the contact region 15.
[0103] FIGS. 4a and 4b show a component of an electric machine which is equipped with a plurality of stranded wires 10 according to FIG. 3. The component may be, for example, the stator 23 of an electric machine. Other components in which stranded wires 10 of this kind are used are possible. The stranded wires 10 have different lengths. It can be clearly seen in FIG. 4b, in particular in the illustration of a detail of the stator slots 24, that the shaped stranded wires have the same cross section as a stator slot 24. In the example according to FIG. 4b, the cross section is trapezoidal. Other cross-sectional shapes are possible. In the example according to FIG. 4b, two shaped stranded wires 10 are arranged in the same stator slot 24.
[0104] With reference to electric machines, active length means that line section of a winding that is located within magnetically active parts. In the case of a stator, the active length of a segment conductor, such as of a shaped stranded wire for example, corresponds to that section of the segment conductor that is located within a stator slot. Non-active length components are accordingly located outside the stator slot. FIGS. 5a-c and 6a-b illustrate the problem which arises when individual wires 10 or partial stranded wires 18 are stripped of insulation before being twisted.
[0105] FIG. 5a schematically illustrates the windings of an individual wire 12 which winds along an outer circumference of a conductor section with a length L1. One complete turn of the wire is called a lay, and half a turn of the wire is called half a lay or a half-lay. The lengths L2 and L3 indicate the lay or half-lay length, wherein these lengths do not refer to the actual length of the individual wire 12 but rather to the effective length parallel to the conductor profile.
[0106] FIG. 5b shows an approximate plan view of the additional diversion which an individual wire 12 has to cover over the course of a lay length L3 as a dotted line. The solid-line rectangle illustrates the conductor core around which the individual wire 12 shown is wound.
[0107] FIG. 5c shows the difference in length L4 (FIG. 5c) between the direct path (for example of a core wire), that is to say the half-lay length L3, and the individual wire which has half a lay. The half-lay length L3 is depicted horizontally. Half the circumference L5 of the conductor core is depicted vertically. The connecting line is (owing to the wire diameter which is not taken into consideration only in a first approximation) the resulting length of the individual wire for covering a half-lay length. The perpendicular from the direct path to the resulting length illustrates the difference in length.
[0108] The different layers 20, 21, 22 (cf. FIG. 1) have different lengths.
[0109] FIGS. 6a and b show the two options for producing a twisted litz wire, the ends of which terminate flush.
[0110] According to FIG. 6a, the individual wires 12 or the partial stranded wires 18 for the various layers 20, 21, 22 (see FIG. 1) are produced with different lengths. The individual wires 12 or the partial stranded wires 18 are stripped of insulation along partial lengths 13 of equal length. The partial lengths 13 of the individual wires 12 of different length are therefore of equal length and offset in relation to one another on account of the different individual wire lengths. The length of the individual wires 12 or partial stranded wires 18 according to FIG. 6a is dimensioned such that the non-insulated partial lengths 13 are arranged at the same level in the twisted state and therefore form the contact region 15 of the stranded wire. Specifically, the partial lengths 13 are arranged such that those ends 16 that are at the rear in the transportation direction of the partial stranded wires 18 or individual wires 12 during production and those ends 17 that are at the front in the transportation direction are arranged flush one above the other in each case. The transportation direction runs from left to right in FIGS. 6a and 6b. In other words, the front ends 17 form a termination edge of the stranded wire or of the partial stranded wire 18 or of the individual wires 12. Partial lengths 13 which are not insulated and which terminate flush at both ends of the partial lengths 13 are likewise arranged at the other end of the individual wires 12 or partial stranded wires 18.
[0111] The insulation layer 11 is applied between the partial lengths 13 on both sides of an individual wire 12 or of the partial stranded wire 18.
[0112] According to FIG. 6b, the individual wires 12 or partial stranded wires 18 are of equal length. The partial lengths 13 at one end of the individual wires 12 or partial stranded wires 18 are of different length. The length of the partial length 13 of the innermost individual wire 12 for the first layer 20 is the longest. The length of the partial lengths 13 decreases radially to the outside (with respect to the stranded wire 10). The outermost partial length 13 or the partial length 13 of the outermost individual wire 12 the shortest partial length 13. In the event of twisting, the starting edges 16 of the partial lengths 13 which are stripped of insulation will come to lie flush one above the other. The end edges 17 of the wires 12 will not terminate flush with one another, so that additional cutting is necessary here and waste is produced.
[0113] On the other side of the individual wires 12 or 18, the partial lengths 13, which are not insulated, are of the same length.
[0114] FIG. 7 shows an exemplary embodiment of an apparatus for producing stranded wires, specifically an individual wire production line. In this case, a plurality of individual wires are usually produced at the same time. These are separated for the purpose of treating the individual wires. This is understood to mean a production step in which the individual wires 12 are spaced apart from one another such that the individual wires 12 are treated substantially individually.
[0115] The apparatus has a device 30 for applying an insulation layer 11 to the individual wire 12. Specifically, said device is an insulation bath through which the individual wire 12 is passed in order to apply the insulation layer 11 which consists of enamel. Suitable means 35 which uniformly coat the individual wire 12 in a manner which is known per se are provided for this purpose. The individual wire 12 is then passed through a drying device 36. The dried individual wire 12 is then partially stripped of insulation in a device 32 for removing the insulation layer 11. To this end, corresponding means 34 for individually removing the insulation layer 11 along a partial length 13 of the individual wires 12 are provided. The means 34 for individually removing the insulation layer 11 can comprise a laser device. The individual wire 12 is then trimmed by a device 37 to the length desired here.
[0116] Said figure also illustrates a synchronization device 50 which determines the position and length of the individual partial lengths 13, which are stripped of insulation, of the individual wires 12, here illustrated by an imaging process. Depending on the position and length of the partial sections which are stripped of insulation relative to one another, the synchronization device 50 sends control commands to the device 32 in order to adjust the activity of the device 32 as required.
[0117] The apparatus according to FIG. 7 is a batchwise production apparatus which is illustrated in two variants in FIGS. 8a and 8b. FIGS. 8a and 8b show a plurality of individual wires 12 which are arranged separately and are fastened on a conveyor belt 39 by fixing means 38. The conveyor belt 39 moves the separated individual wires 12 in the device (from left to right in the figures). The two laser devices (means 34) are arranged such that they can apply a laser beam to the axial ends of the individual wires 12 in order to strip insulation. In the variant according to FIG. 8a, the individual wires 12 are of different length, as described in more detail in connection with FIG. 6a. The variant according to FIG. 8b relates to an embodiment of the production method in which the individual wires 12 are of equal length. The partial lengths 13 are of different length.
[0118] FIG. 9a shows a variant with insulation-stripped regions of different length (here indicated for a three-layer stranded wire) which are twisted and then trimmed to length. The apparatus can comprise forging rolls 40 in order to shape and/or additionally to compress the twisted stranded wire into a desired outer contour. All of the wires run at the same speed at the output of the twisting device or in general the bringing-together device 31, so that a corresponding V pattern (given a corresponding longitudinal section through the stranded wire) is (approximately) produced in the insulation-stripped region of the twisted stranded wire. The V region is a waste product in the sense that it cannot be used as a contact-making region (owing to the residual enamel) or as an insulation section between the contact-making region and the active length (owing to the partially missing insulation). This increases the gross length of the shaped stranded wire. Equally, the requirements in respect of precision of the insulation-stripped sections are more modest than in the case of the following production processes since the regions of overlap can be selected generously for the start and also the end of the stripped insulation. A method in which modest requirements are made in respect of the synchronization of the individual wires is illustrated here.
[0119] FIG. 9b shows a variant of the method according to FIG. 9a in which the insulation-stripped sections (partial lengths 13) of equal length have to be placed so precisely that they come to lie flush one above the other in the event of twisting. On account of the required precision/synchronization, a precise and rapid-response insulation-stripping method, such as laser evaporation, is particularly advantageous here. (The arrows indicate the different feed speeds of the individual wires (or partial stranded wire) of each layer in which the individual wires run at a differential speed which is suitable for compensating for the difference in length of the various wires depending on position, so that the start and the end of the insulation sections come to lie flush one above the other.
[0120] FIG. 10 shows a further exemplary embodiment of a production variant of a shaped stranded wire which is composed of partial stranded wires 18. The method according to figure pull transfers the principle of the method according to FIG. 9b from the production of stranded wires from individual wires 12 to the production of stranded wires by partial stranded wires 18. In this case, instead of the individual wires 12, partial stranded wires 18 with corresponding contact-making regions 15 are brought together in order to ultimately form a final stranded wire 10 which has a single contact region 15 or two contact regions 15 at both ends of the stranded wire. A two-stage method for producing a second-grade stranded wire is illustrated by way of example. Reference symbol 41 denotes guide devices which provide for parallel supply of the partial conductors into a bringing-together device 31. It is possible for the method according to FIG. 9a or 9b to be executed as a partial step in the method according to FIG. 10, for example for the method from FIG. 9a or 9b to be executed before the method illustrated here. It is equally possible to execute the method from FIG. 9a or 9b during or after the method illustrated here. This means, for example, that a partial stranded wire 18 in the function of a core wire is wound with further individual wires at the outer circumference. However, the option of entwining an individual conductor 12 in the function as a core wire with a plurality of partial stranded wires at the outer circumference is also covered. Obvious variations of the example shown here are hereby suggested to a person skilled in the art.
[0121] FIGS. 11 and 12 illustrate the order of two exemplary production processes. FIG. 11 illustrates a process sequence with continuous production, and FIG. 12 illustrates a process sequence with batchwise production. For both production processes, wires are provided (S10) as continuous wires, for example in coil form, and are insulated (S20), for example, in accordance with the partial method shown in FIG. 7. In accordance with the method from FIG. 11, a plurality of wires are then guided in parallel (S30) analogously to FIG. 9a or 9b, so that the wire sections are in coherent form, but are separated and can be individually stripped of insulation (S40) at the desired points. The individual wires which are prepared in this way are stranded (S50) in one or more twisting or stranding devices to form a stranded wire in such a way that they have clearly delimited contact sections. The continuous enameled stranded wire is then compressed in a method which is suitable for continuous production, for example roll forging, and shaped (S60) into a desired outer contour. The continuous shaped stranded wire which is then produced are severed in the middle of the contact points which are provided by the partial stripping of insulation, in order to produce (S70) shaped stranded wires with contact points on both sides. The individual wires are then electrically and mechanically connected to one another (S80) in the contact region. The shaped stranded wire which is now present could then be inserted into a slot of a stator.
[0122] The method according to FIG. 12 differs from the method 11 in respect of steps S25, S35, S45 and S65. In S25, a continuous wire is trimmed, for example, to one or more lengths according to the embodiments in FIG. 6a or 6b, the individual wires or enameled wire pieces are separated (S35) and stripped of insulation (S40) over a partial length at the ends. A certain number of prepared individual wires are bundled and twisted to form a stranded wire in such a way that a clearly defined contact region is produced (S45) at the end. This partial step can be repeated several times and hierarchically structured in order to produce higher-order stranded wires. The stranded wire is then compression molded (S65), for example in a lifting press. In step S80, the individual wires are electrically and mechanically connected in the contact region of the shaped stranded wire. Step S80 can precede or follow step S65. Advantages of the solution according to the invention are in particular: [0123] a uniform quality level for all of the shaped stranded wires [0124] increased reliability given the same quality [0125] improved thermal, electrical and mechanical contact [0126] shorter cycle times since the required contact forces, times andif applicablewelding currents for connecting the head region can be lower on account of the lack of insulation [0127] use of fewer resources, in particular when cutting off the end section with an enamel overhang is dispensed with [0128] improved further processability for connection to form conductor loops:
[0129] Owing to a higher degree of compaction of the head end, in association a smaller head geometry and ultimately increased accessibility during assembly, for example for fitting interconnection webs [0130] shortening of installation space I: less ingress of heat into critical regions and as a result shortening of shaped stranded wires given the same insulation performance: owing to lower processing loads (current intensity, time, force), less heat is developed, as a result of which the main insulation and also the individual wire insulation of a shaped stranded wire is acted on to a lesser extent in the direction of the active length, that is to say in the direction of the stator slot, and therefore the safety distance between the head end and the active length of the shaped stranded wire can be shortened. (The possible shortening of installation space is considerable and moves in the region of a few mm; the previous ingress of heat led to brittle zones beneath the sleeves of around 6 mm on each side of the shaped stranded wire which no longer ensure reliable insulation) [0131] shortening of installation space II: shortening of installation space when using sleeve lugs or tabs since the enamel residues do not have to be captured in a separate dead space which would increase the size of the sleeve lengththe enamel residues are conductive on account of their carbon content and therefore may not either enter the active part (stator slot) nor establish contact with other conductor elements or contaminate contact elements.
[0132] Selective delimiting of insulated and non-insulated regions of the shaped stranded wire results, amongst other things, in: [0133] shortening of installation space III: when the enamel insulations of all of the individual wires of a shaped stranded wire are cut off in a flush manner, construction can be shorter since the spacing of (stator end)(insulation end of the individual wire) and also (individual wire insulation end)(individual wire end=shaped stranded wire end) for all of the individual wires is the same. Therefore, the minimum insulation length (from the end of the active length to the start of the enameled wire which is stripped of insulation) for the creepage resistance or flashover resistance and at the same time the minimum contact-making length (start of enameled wire which is stripped of insulation to enameled wire end=shaped stranded wire end can be selected. This is otherwise not possible in the event of twisting on account of the unequal individual wire lengths.
[0134] A preferred exemplary embodiment of the invention is the continuous production according to FIG. 9b and, respectively, FIG. 11.
