JP2015154022A - reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor capable of suppressing dielectric breakdown between coil turns caused by vibrations even without using a cast resin and capable of cooling a coil.SOLUTION: The reactor includes a coil 10 formed by winding an element wire 11 formed by covering a surface of a conductor wire 11a with an insulation coating layer 11b. A surface of the element wire 11 includes: a region in which an engineering plastic 12 is bonded to portions 11c, 11d facing a coil turn to which each coil turn is neighboring; and a region in which the engineering plastic 12 is exposed without being bonded.

Description

  The present invention relates to a reactor, and more particularly to a reactor having no casting resin.

  A reactor including a coil is used for a power conversion device such as a DC-DC converter mounted on a vehicle such as a hybrid vehicle, an electric air vehicle, or a fuel cell vehicle. The structure of the reactor is disclosed in Patent Document 1, for example. FIG. 5 shows a cross-sectional view of a conventional general reactor 90 as described in Patent Document 1. In the reactor 90, a coil 91 inserted through a magnetic core (core) 92 is accommodated in a case made up of a side wall portion 93 and a bottom plate portion 94. The space inside the case is filled with casting resin (sealing resin) 95. The casting resin 95 has a role of maintaining insulation of the coil 91 and a role of promoting cooling of the coil 91. The casting resin 95 penetrates between the coil turns of the coil 91 and has an effect not only on the insulation of the entire coil 91 but also on the insulation between the coil turns.

JP 2012-253384 A

  In the conventional general reactor 90, the casting resin 95 filled in the case may be cracked due to a temperature change or the like. Then, the function of the casting resin 95 as described above is not sufficiently performed. Therefore, there is room to consider manufacturing a reactor that can insulate and cool the coil 91 without using the casting resin 95.

  However, when the casting resin 95 is not used, the coil 91 vibrates due to the vibration of the vehicle on which the reactor 90 is mounted, and friction is generated between the coil turns. If friction occurs between the coil turns, the insulation coating made of enamel or the like formed on the outer periphery of the wire of the coil 91 may be worn, and insulation between the coil turns may not be maintained.

  The problem to be solved by the present invention is to provide a reactor capable of suppressing the dielectric breakdown between coil turns due to vibration and cooling the coil without using a casting resin.

  In order to solve the above-described problems, a reactor according to the present invention has a coil formed by winding a wire in which a surface of a conductor wire is covered with an insulating coating layer, and each coil turn is adjacent to the surface of the wire. The gist of the invention is to have a region where the engineering plastic is bonded to a portion facing the coil turn, and a region where the engineering plastic is exposed without being bonded.

  Here, the engineering plastic may have a melting point of 200 ° C. or higher and lower than the melting point of the insulating coating layer.

  Moreover, it is preferable that the engineering plastic is bonded to both of the two opposing coil turns.

  And it is preferable that the said coil is a square coil, and the said engineering plastic is adhere | attached on the corner | angular part of the said square coil at least.

  Moreover, it is preferable that the engineering plastic is continuously bonded over the entire axial direction of the strand.

  According to the reactor according to the invention, the engineering plastic is bonded to the surface of the element wire at a portion where a certain coil turn faces the adjacent coil turn. As a result, even when the entire coil is vibrated and vibration occurs between the coil turns, the wires constituting each coil turn are in direct contact with each other at least at the site where the engineering plastic is bonded due to the presence of the engineering plastic. This prevents the insulating coating layer from being worn by friction between coil turns. Accordingly, the insulation between the coil turns is maintained even when the coil receives vibration. In particular, engineering plastics have high mechanical strength compared to general-purpose plastics, which can effectively suppress the abrasion of the insulating coating layer, and further, such effects can be achieved by having high heat resistance. Can be maintained even in a high temperature environment. On the other hand, since the part which exposed without engineering plastics adhere | attaching on the strand which comprises a coil, this part can be used for cooling of a coil. Further, since it is not necessary to use a casting resin, the entire reactor is simplified and lightened, and productivity is improved.

  Here, when the engineering plastic has a melting point of 200 ° C. or higher and lower than the melting point of the insulating coating layer, it can exhibit high heat resistance and heat the engineering plastic without melting the insulating coating layer. And then melted and bonded to the coil wire.

  In addition, when the engineering plastic is bonded to both of the two adjacent coil turns, the engineering plastic fixes the adjacent coil turns to each other. Since the vibration occurring in the meantime is reduced, the dielectric breakdown due to the vibration can be effectively suppressed.

  When the coil is a square coil and the engineering plastic is bonded to at least the corner of the square coil, the distance between the coil turns is determined by the difference in the dimensions of the outer peripheral surface and the inner peripheral surface of the coil. Since the engineering plastic is present between the coil turns at the corners where the insulating coating layer is likely to be narrowed and thus easily wear due to vibration, the dielectric breakdown between the coil turns can be effectively suppressed.

  In addition, when engineering plastics are continuously bonded over the entire axial direction of the strands, the engineering plastics are arranged in the entire area along the coil winding direction, so that insulation between coil turns is possible. The effect of suppressing destruction is particularly high. Moreover, the structure which the engineering plastics adhere | attached on the coil strand can be simply formed by heating after winding a thread-like or string-like engineering plastic along a coil.

It is a perspective view which shows the coil which comprises the reactor concerning one Embodiment of this invention. It is the schematic which shows the structure of the said coil, (a) is the figure seen from the central axis of a linear part, (b) is AA sectional drawing in (a). It is the top view which extracted one coil turn of the said coil. It is a schematic diagram which shows an example of the manufacturing method of the said reactor. It is sectional drawing which shows the conventional general reactor (the hatching which shows a cross section is abbreviate | omitting suitably).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1-3, the coil 10 which comprises the reactor concerning one Embodiment of this invention is shown. The coil 10 is formed by spirally winding an element wire 11 in which the outer periphery of a conductor wire 11a is covered with an insulating coating layer 11b. The coil 10 has an overall shape in which two straight portions 10a, 10a are aligned in the winding direction.

  The conductor wire 11a is made of metal such as copper or copper alloy, aluminum or aluminum alloy, for example. The insulating coating layer 11b is made of an enamel material typified by polyamideimide, for example. Moreover, as a shape of the strand 11, it is preferable that it is a flat wire from a viewpoint of raising the cooling property of the coil 10 and raising the density of winding. The coil 10 is preferably formed as a square coil having a shape obtained by rounding the corners of a prism, from the viewpoint of ease of fixing and the like.

  A magnetic core 20 is inserted into the hollow portion V of each linear portion 10 a of the coil 10. The magnetic core 20 has the same configuration as a known magnetic core, for example, the same as the magnetic core 92 shown in FIG. 5 in which core portions 92a made of a magnetic material and gap portions 92b made of a nonmagnetic material are alternately connected. Can be applied.

  The coil 10 in which the magnetic core 20 is inserted is appropriately fixed to a mounting surface such as a bottom plate (not shown), and input / output terminals, sensors, and the like are attached thereto, and assembled as a reactor. Here, in the conventional reactor 90 shown in FIG. 5, the coil 91 is housed in a case made up of the bottom plate portion 94 and the side wall portion 93, and the space in the case is filled with the casting resin 95, but this embodiment is concerned. In the reactor, casting resin is not used. That is, a member corresponding to the side wall portion 93 in FIG. 5 is not necessary, and the member is incorporated in a DC-DC converter or the like while being attached to an attachment surface corresponding to the bottom plate portion 94.

  The reactor according to the present embodiment is characterized in that an engineering plastic layer 12 is disposed between coil turns (each pitch of the spiral) of the strands 11 constituting the coil 10. That is, in each coil turn, an engineering plastic layer 12 made of engineering plastic (engineering plastic) is formed on the surface of the strand 11 at a portion facing the adjacent coil turn. The engineering plastic layer 12 is bonded to the surface of the strand 11 by contacting and welding the surface of the strand 11.

  The engineering plastic layer 12 may be formed not only on the part between the coil turns but also on the part other than the part between the coil turns, such as the outer peripheral surface and the inner peripheral surface of the coil 10, but the surface of the strand 11 constituting the coil 10. The coil 10 is not covered entirely, and the coil 10 is not covered with the engineering plastic layer 12, and the region where the element wire 11 (the insulating coating layer 11b) is exposed coexists with the region covered with the engineering plastic layer 12. . Here, the bare wire 11 means that it is exposed to the surrounding environment where the reactor is installed, such as the atmosphere, and is covered with a resin other than the engineering plastic layer 12, such as a casting resin. Does not include state.

  Since the engineering plastic layer 12 is formed between adjacent coil turns of the coil 10, even if the coil 10 receives vibration and vibration occurs between adjacent coil turns, that is, relative displacement between the coil turns occurs, at least In the portion where the engineering plastic layer 12 exists, the surfaces of the strands 11 are prevented from directly contacting each other between coil turns. The vibration of the coil 10 is caused by the vibration of the vehicle on which the reactor is mounted. If the adjacent coil turns come into direct contact with each other due to this type of vibration and collide with each other to cause friction, the insulating coating layer 11b on the surface of the strand 11 may be worn. Then, the insulation between coil turns is destroyed, a short circuit (rare short) occurs, and the output characteristics of the reactor change. In addition, rapid heat generation occurs due to a large current flowing through the site where the short circuit occurs. The heat generation may affect other members arranged around the coil 10 such as melting of the solder part or peeling of the adhesive part, and may lead to stoppage of the vehicle while traveling or irreversible damage to the member. There is.

  On the other hand, in the reactor according to the present embodiment, the engineering plastic layer 12 is formed between the coil turns, and the strand 11 does not directly contact between the coil turns. The insulating coating layer 11b on the surface of the element wire 11 is less likely to be worn at the portion covered with. Therefore, the short circuit between coil turns and the accompanying heat generation are suppressed. Even when a large impact is applied to the coil 10, the insulating coating layer 11 b of the element wire 11 is protected by deforming or destroying the engineering plastic layer 12. In particular, engineering plastics are particularly excellent in the effect of protecting the insulating coating layer 11b from abrasion because they have a higher strength than general thermoplastic resins (general-purpose plastics). Moreover, since engineering plastics have high heat resistance, even if the temperature becomes high due to heat generated by energization of the coil 10, it is difficult to melt and soften, and the high protective effect on the insulating coating layer 11b is easily maintained.

  On the other hand, the entire surface of the wire 11 constituting the coil 10 is not covered with the engineering plastic layer 12, but a part of the surface is exposed, so that even when a current is applied and the coil 10 generates heat, Cooling (heat radiation) can be performed through the exposed portion. That is, it is possible to achieve both suppression of dielectric breakdown between coil turns and securing of cooling performance.

  If the engineering plastic layer 12 is formed on at least one of the surfaces of the strands 11 facing each other between two adjacent coil turns, the wear of the insulating coating layer 11b between the coil turns is suppressed. Can contribute. That is, in FIG.2 (b), the engineering plastic layer 12 is adhere | attached on both the 1st opposing surface 11c and the 2nd opposing surface 11d which are the mutually opposing surfaces of two coil turns, and the 1st opposing surface 11c and The second opposing surface 11d is formed so as to be connected, but the engineering plastic layer 12 may be formed by adhering to the surface of either the first opposing surface 11c or the second opposing surface 11d. Or when forming the engineering plastic layer 12 in both the 1st opposing surface 11c and the 2nd opposing surface 11d, the engineering plastic layer 12 formed in those 2 surfaces is not necessarily integrated like FIG.2 (b). The first opposing surface 11c and the second opposing surface 11d do not need to be continuously connected, and may be formed as two independent coating layers.

  However, as shown in FIG. 2B, the engineering plastic layer 12 is bonded to both the first facing surface 11c and the second facing surface 11d facing each other between adjacent coil turns so as to connect the two. If it is arranged, it is possible to effectively prevent the insulation coating layer 11b from being worn by vibration. One reason is that, since the engineering plastic layer 12 is formed thick, the impact applied to the first opposing surface 11c and the second opposing surface 11d by vibration can be effectively mitigated. In addition, the engineering plastic layer 12 is formed over the entire distance between the first facing surface 11c and the second facing surface 11d, and is bonded to both the first facing surface 11c and the second facing surface 11d, thereby adjacent coils. The turns are fixed to each other via the engineering plastic layer 12, and even if the entire coil 10 receives vibration, the adjacent coil turns are relatively less likely to be displaced. As described above, wear of the insulating coating layer 11b when the coil 10 receives vibration is also suppressed by the effect of limiting the vibration itself between the coil turns.

  As described above, if the engineering plastic layer 12 is formed on a part of the surface of the strand 11 including the portions (the first facing surface 11c and the second facing surface 11d) facing each other between the coil turns, how It may be formed at any position. However, as shown in FIG. 2 (b), it is desirable that the coil 10 is formed at an inner portion close to the central axis C of the coil 10. In the coil 10, because of the structure that the inner peripheral surface has a smaller cross-sectional size than the outer peripheral surface, the strands 11 forming each coil turn are relative to each other as schematically shown in FIG. In particular, the outside is thin (thin) and the inside is thick (thick) (winding thick). That is, the distance between the coil turns is narrower on the inner side than the outer side of the coil 10, and when the coil 10 receives vibration, the contact of the element wire 11 between the coil turns is more on the inner side than the outer side of the coil 10. As a result, the insulating coating layer 11b is easily worn. Therefore, by disposing the engineering plastic layer 12 between the coil turns of the inner portion of the coil 10, it is possible to more effectively suppress the dielectric breakdown due to the abrasion of the insulating coating layer 11b than when disposed in the outer portion. In particular, when the strand 11 is a flat wire, the winding thickness is likely to increase, and thus the effect of disposing the engineering plastic layer 12 on the inner portion is great. Further, when the engineering plastic layer 12 is disposed on the inner portion of the coil 10, the exposed portion that is not covered with the engineering plastic layer 12 is relatively disposed on the outer side, which increases the efficiency of cooling (dissipating heat) of the coil 10. In addition, it is advantageous.

  Further, it is advantageous that the engineering plastic layer 12 is formed at least in the corner portion shown as the region B in FIG. This is because, in a square coil, the thickening of winding occurs at the corner B. That is, in the inner part of the corner portion B, the interval between the coil turns is narrow, and the insulation coating layer 11b is easily worn by vibrations. It can suppress especially effectively.

  The ratio of the part where the engineering plastic layer 12 is formed and the part that is exposed without being formed may be appropriately selected in consideration of the expected degree of vibration and the degree of heat generation of the coil 10. As the ratio of the region covered with the engineering plastic layer 12 is increased, the effect of suppressing the dielectric breakdown between the coil turns due to vibration is enhanced. As the ratio of the region covered with the engineering plastic layer 12 is decreased, cooling (heat radiation) is increased. Efficiency is increased.

  From such a viewpoint, as shown in FIG. 3, even if the engineering plastic layer 12 is continuously formed over the entire axial direction of the element wire 11 (winding direction of the coil 10), for example, only the corner portion B is formed. Thus, even if it forms discontinuously only in a required part, it does not matter. However, the continuous formation as shown in FIG. 3 can effectively suppress the wear of the insulating coating layer 11b over the entire area of the coil 10. Moreover, the engineering plastic layer 12 which continued along the axial direction of the strand 11 can be simply formed by winding the engineering plastic yarn 12a along the coil 10 and heating it as described later.

  The engineering plastic layer 12 may be made of any engineering plastic. Examples include polyamide, polybutylene terephthalate, polyacetal, polycarbonate, syndiotactic polystyrene, polysulfone, polyethersulfone, polyphenylene sulfide, polyamideimide, polyimide, polyoxybenzylene, polyetheretherketone, polyetherimide, polyphenylene ether, etc. can do. Two or more of these may be used in combination. Furthermore, additives such as coloring pigments, viscosity modifiers, anti-aging agents, inorganic fillers (fillers), storage stabilizers, and dispersants may be added as appropriate to the engineering plastics.

  Considering the temperature rise due to heat generation when the coil 10 is energized, the engineering plastic constituting the engineering plastic layer 12 preferably has a melting point of 200 ° C. or higher. Then, the engineering plastic layer 12 exhibits high heat resistance, and has an excellent function of protecting the insulating coating layer 11b of the wire 11 from abrasion even in a high temperature environment. On the other hand, the engineering plastic constituting the engineering plastic layer 12 preferably has a melting point lower than the melting point of the insulating protective layer 11b. As a result, as described below, the engineering plastic material is disposed between the coil turns of the coil 10 and heated, so that the engineering plastic is melted without melting the insulating coating layer 11b. Can be welded. Specifically, when the insulating coating layer 11b is made of an enamel material such as polyamideimide, the engineering plastic preferably has a melting point of 350 ° C. or lower. As an engineering plastic having a melting point of 200 ° C. or higher and 350 ° C. or lower and suitably used for constituting the engineering plastic layer 12, polyphenylene sulfide (PPS) can be exemplified.

  In the reactor manufacturing process, as a method of adhering the engineering plastic layer 12 to the surface of the wire 11 of the coil 10, an engineering plastic is placed at a predetermined portion between the coil turns of the coil 10 and then melted by heating. The method of cooling can be taken. As a method of arranging engineering plastic between coil turns, a method using engineering plastic yarn 12a in which engineering plastic is formed into a string or string can be mentioned.

  Specifically, as shown in FIG. 4, the engineering plastic yarn 12a may be wound around the wire 11 between the coil turns of the coil 10 that has been formed into a wound shape. If this is heated to melt the engineering plastic yarn, the engineering plastic layer 12 can be continuously formed along the axial direction of the strand 11 as shown in FIG. As described above, the corner portion B of the square coil is greatly thickened and the interval between the coil turns is narrow. Therefore, when the engineering plastic yarn 12a is wound between the coil turns, It is particularly easy to catch on the corner B. Thereby, the engineering plastic layer 12 can be formed in the region including the corner portion B with high accuracy. Further, if an engineering plastic yarn 12a having a diameter equal to or larger than the interval between the coil turns is used and arranged between the coil turns so as to be pushed in, as shown in FIG. It is easy to form a state where the engineering plastic layer 12 is adhered to both sides of the turn.

  In addition to disposing the engineering plastic yarn 12a between the coil turns of the coil 10 that has already been wound as shown in FIG. 4, the engineering plastic yarn 12a is placed along the elongated strand 11 before winding, A method of winding the engineering plastics 12 together to form them into a shape is conceivable. However, the method of winding the engineering plastic yarn 12a between the coil turns of the coil 10 formed as shown in FIG. 4 makes it easier to reliably place the engineering plastic yarn 12a at the portion between the coil turns, particularly at the corner B.

  As a method of arranging the engineering plastic between the coil turns of the coil 10, a method of inserting the engineering plastic formed in a comb-teeth shape in accordance with the interval of the coil turns between the coil turns in addition to the method of using the engineering plastic 12a as described above. Can be considered. The method using the engineering plastic yarn 12a is particularly suitable for continuously forming the engineering plastic layer 12 along the axial direction of the strands, whereas the method using the comb teeth is the engineering plastic layer such as only the corner B. It is suitable for forming 12 discontinuously along the axial direction of the strand.

  As described above, in the reactor according to the present embodiment, the engineering plastic layer 12 is formed on the portion of the wire 11 forming the coil 10 including the surface disposed between the coil turns, and the remaining portion is exposed. As a result, the occurrence of dielectric breakdown between the coil turns when the coil 10 receives vibration is suppressed, and the coil 10 can be cooled (heat radiation) with high efficiency. In the conventional general reactor 90, the casting resin 95 is filled inside the case for accommodating the coil 91, and the insulation between the coil turns is ensured by the casting resin 95 that has entered the gap between the coil turns. Further, the coil 91 has been cooled by allowing heat to escape to the bottom plate 94 of the case provided with a cooling mechanism as appropriate through the casting resin 95. However, in the reactor according to the present embodiment, insulation between coil turns and cooling of the coil 10 can be performed without using a casting resin due to the above configuration. And by not using casting resin, it is not necessary to use the case provided with a side wall part. Thereby, compared with the past, the whole reactor can be simplified and reduced in weight, and productivity can be improved.

  Examples of the present invention and comparative examples are shown below. In addition, this invention is not limited by these Examples.

<Preparation of test sample>
[Example 1]
The coil and core which have the shape shown in FIGS. 1-3 were produced, and those combination was formed. In producing the coil, the enamel-coated wire was wound into a predetermined rectangular shape, and then the PPS yarn was wound between the coil turns, the coil was heated to the melting point of PPS, and PPS was welded to the coil wire. Then, the coil was fixed to the bottom plate, and terminal connection etc. were performed and assembled as a reactor.

[Comparative Example 1]
A similar reactor was produced using polyethylene yarn instead of the PPS yarn of Example 1, and a reactor according to Comparative Example 1 was obtained.

<Test method>
[Evaluation of coating condition]
Each reactor was subjected to a vibration test in accordance with an automobile part vibration test method defined in JIS D1601. Then, after the vibration test, visually check whether there is any abnormality in the coating state, such as peeling, on the insulation coating layer (enamel coating layer) on the surface of the wire arranged in the region between the coil turns. went. Those in which no abnormalities such as peeling were found in the insulating coating layer were evaluated as acceptable “◯”, and those in which abnormalities such as peeling were observed were determined as “failed”.

[Reactor characterization]
Before and after the vibration test, the electrical characteristics of the reactor were evaluated, and it was confirmed whether or not the characteristics were deteriorated by the vibration test. Those in which the characteristics were not deteriorated were evaluated as acceptable “◯”, and those in which the characteristics were deteriorated or those in which the electrical characteristics could not be evaluated were determined as unacceptable “x”. Moreover, it was confirmed with respect to the reactor of Example 1 that the characteristics did not deteriorate with time due to the heat generated by the coil during the characteristic evaluation.

<Test results>
Table 1 shows the results of the evaluation of the covering state after the vibration test and the characteristics evaluation of the reactor for the reactors according to the examples and the comparative examples.

  As shown in Table 1, in the reactor of Comparative Example 1 using polyethylene, no abnormalities in the coating state such as peeling of the insulating coating layer were observed even after the vibration test. However, during the characteristic evaluation, the polyethylene resin was melted by the heat generated by the coil, and the characteristic evaluation could not be performed. This can be achieved by placing polyethylene between the coil turns to prevent the insulation coating from vibration, but because of its low heat resistance, it can be used by placing it between the coil turns at high temperatures. Indicates that it is not suitable.

  On the other hand, in the reactor using PPS, even if it passed through the vibration test, abnormality, such as abrasion, did not generate | occur | produce in the insulation coating layer of a strand, and the characteristic did not fall from an initial state. That is, by disposing the engineering plastic PPS between the coil turns, the insulating coating layer is prevented from being damaged by vibration. It was also found that the high heat resistance of PPS does not melt even when the coil generates heat, and can maintain the role of protecting the insulating coating layer between coil turns. A reactor having high resistance to the heat generation of the coil has been obtained in combination with the fact that the coil that has generated heat is cooled in the exposed portion that is not covered with PPS, and the reactor characteristics are not deteriorated over time due to heat generation. It was shown that.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the said embodiment and Example at all, and various modification | change is possible in the range which does not deviate from the summary of this invention. .

DESCRIPTION OF SYMBOLS 10 Coil 11 Strand 11a Conductor wire 11b Insulation coating layer 11c 1st opposing surface 11d 2nd opposing surface 12 Engineering plastic layer 12a Engineering plastic yarn 20 Magnetic core

Claims (5)

Having a coil formed by winding a conductor wire whose surface is covered with an insulating coating layer;
The surface of the element wire has a region where the engineering plastic is bonded to a portion where each coil turn is opposed to the adjacent coil turn, and a region where the engineering plastic is exposed without being bonded. .   The reactor according to claim 1, wherein the engineering plastic has a melting point of 200 ° C. or higher and lower than a melting point of the insulating coating layer.   3. The reactor according to claim 1, wherein the engineering plastic is bonded to both of mutually opposing portions of two adjacent coil turns.   The reactor according to any one of claims 1 to 3, wherein the coil is a square coil, and the engineering plastic is bonded to at least a corner portion of the square coil.   The reactor according to any one of claims 1 to 4, wherein the engineering plastic is continuously bonded over the entire axial direction of the element wire.

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