Laminate, motor coil wire, motor, and method for manufacturing the same.

Abstract

The present invention provides a laminate that can provide sufficient bonding force between multiple motor coil conductors and between motor coil conductors and insulating paper within the slots of a motor stator, a motor coil conductor using the above laminate, and a motor using the above motor coil conductor. [Solution] A laminate comprising an adhesive layer 1, an insulating film 2 made of polyphenylene sulfide, and an adhesive layer 3 in this order, wherein the adhesive layer is heat-foaming and the adhesive layer is non-foaming.

Description

Technical Field

[0001] The present invention relates to a laminate, a coil conductor for a motor, a motor, and methods for manufacturing these.

Background Art

[0002] The stator constituting a motor is formed from a stator core formed by laminating steel plates provided with an annular yoke, a plurality of teeth protruding radially inward from the yoke, and slots formed between adjacent teeth. For example, a coil pre-wound with a conductor is fitted around these teeth and fixed, thereby manufacturing the stator core. When installing the coil on this stator core, in order to ensure the insulation between the stator core and the coil, it is common to place insulating paper in the slots of the stator core and then fit and install the coil around the teeth. After the insulating paper is arranged in the slots and the coil is arranged around the teeth, for example, varnish (adhesive) is impregnated into the coil from the coil end, and by curing the varnish, both the stator core and the insulating paper and the insulating paper and the coil are fixed to further ensure the insulation between the stator core and the coil. Here, impregnating with varnish can be expected to have effects such as fixing the coil and the stator core, improving the insulation between the coil and the stator core, sealing the coil, and promoting heat dissipation from the coil by filling the gaps between the coils with varnish.

[0003] Here, Patent Document 1 discloses a technique for performing insulation treatment and fixing the coil by supplying varnish between the stator core and the insulating paper. More specifically, in order to facilitate the supply of varnish, it is disclosed to provide an opening for supplying varnish in the insulating paper.

[0004] ​​​Patent Document 2 discloses an improved insulating sheet that eliminates the method of fixing the stator core and coil by using general insulating paper, placing it in the slots of the stator core, inserting the coil around the teeth, and then dripping varnish, and instead uses an improved insulating sheet that provides excellent adhesion between the stator core and coil, solves problems such as damage to the insulating sheet or the insulating coating of the coil when placing the coil around the teeth, and eliminates the need for large-scale equipment for dripping varnish, as well as a method for fixing coils to a stator core using this insulating sheet.

[0005] Patent Document 3 discloses a method for manufacturing a motor stator, which comprises a stator core made of laminated steel plates having an annular yoke, a plurality of teeth projecting radially inward from the yoke, and slots formed between adjacent teeth, and a coil made of windings wound around the slots of the stator core. The method involves heating and expanding a rectangular sheet-shaped foamed resin sheet, whose surface is at least made of foamed resin, while sandwiched between the inner wall surface of the stator core in the slots and the coil, thereby fixing the coil to the stator core. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-166731 [Patent Document 2] Japanese Patent Publication No. 2013-62911 [Patent Document 3] Japanese Patent Publication No. 2011-244596 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, if there are gaps between the coil wires that make up the coil in the stator of the motor described above, even if electrical insulation between the stator core and the coil wires is ensured due to the gap between the stator core and the coil wires within the slots of the stator core, the fixing force between the coil wires may not be sufficient. Depending on the state in which the motor is rotating and the state of the device such as the vehicle on which the motor is mounted, some vibration may occur in the coil wires. If the coil wires are not fixed with sufficient fixing force, the vibrations in the coil wires may cause the motor to deteriorate prematurely, generate noise, and cause discomfort to the operator of the device.

[0008] Therefore, in view of the above circumstances, the object of the present invention is to provide a laminate that can provide sufficient bonding force between multiple motor coil conductors and between motor coil conductors and insulating paper within the slots of the motor stator, a motor coil conductor using the above laminate, and a motor using the above motor coil conductor. [Means for solving the problem]

[0009] To solve the above problems, a preferred embodiment of the present invention consists of the following configuration. (1) A laminate comprising, in this order, an adhesive layer, an insulating film made of polyphenylene sulfide, and an adhesive layer, wherein the adhesive layer is heat-foaming and the adhesive layer is non-foaming. (2) Furthermore, it is preferable that the laminate of (1) has a thickness of the adhesive layer before foaming of 40 μm or more and 200 μm or less. (3) Furthermore, it is preferable that the laminate of (1) has a thickness of the adhesive layer after foaming that is 2 times or more and 10 times or less than the thickness of the adhesive layer before foaming. (4) It is also preferable that the motor coil conductor comprises the laminate of (1) and a coil conductor, wherein the coil conductor is covered with one layer of the laminate, and the coil conductor is located on the side of the adhesive layer of the laminate with respect to the laminate. (5) It is also preferable that the motor comprises the motor coil wires, insulating paper and slots of (4), wherein the insulating paper and a plurality of the motor coil wires are arranged inside the slots in this order from the stator core side, the spacing between the plurality of motor coil wires is 0.5 mm or more and 1 mm or less, and the plurality of motor coil wires and the motor coil wires and insulating paper are fixed by the foamed adhesive layer. (6) It is also preferable to employ the method for manufacturing a motor coil conductor according to claim 4, which includes a step of covering the coil conductor with the laminate of (1) such that the coil conductor is located on the adhesive layer side of the laminate. (7) It is also preferable to employ the motor manufacturing method described in claim 5, which includes the steps of arranging the motor coil wires and the insulating paper in this order from the stator core side, and arranging a plurality of motor coil wires at intervals of 0.5 mm or more and 1 mm or less. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a laminate that can provide sufficient bonding force between multiple motor coil conductors and between motor coil conductors and insulating paper within the slots of the motor stator, a motor coil conductor using the above laminate, and a motor using the above motor coil conductor. [Brief explanation of the drawing]

[0011] [Figure 1] This is a conceptual diagram of a side view of a laminate according to one embodiment of the present invention. [Figure 2] This is a conceptual diagram of a motor coil conductor covered with a laminate according to one embodiment of the present invention. [Figure 3] This is a conceptual diagram of a cross-section of a motor according to one embodiment of the present invention, in which motor coil wires of different sizes are inserted into slots. [Figure 4]This is a conceptual diagram of the side view of a motor according to one embodiment of the present invention, in which motor coil wires of different sizes are inserted into slots. [Modes for carrying out the invention]

[0012] The laminate of the present invention will now be described. The laminate of the present invention comprises, in this order, an adhesive layer, an insulating film made of polyphenylene sulfide, and an adhesive layer, wherein the adhesive layer is heat-expandable and the adhesive layer is non-expandable. The adhesive layer is located on the surface side of the coil conductors to which the laminate covers, and is required to be heated and expanded to fix the insulating paper located between the coil conductors and between the inner wall surface of the stator core and the coil to the coil. The insulating film is required to be heat-resistant because it is in close proximity to the coil, which is the heat-generating part of the motor, and is also required to be durable in high-temperature oil in addition to providing electrical insulation between the coil and the motor outer shell material.

[0013] Insulating films made of polyphenylene sulfide have excellent heat resistance, moisture resistance, and oil resistance, making them suitable for use as insulating films for motors that require long-term durability in high-temperature environments. Here, the laminate of the present invention will be described with reference to Figure 1. Figure 1 is a conceptual side view of a laminate according to one embodiment of the present invention, in which an adhesive layer 1, an insulating film 2 made of polyphenylene sulfide, and a tack layer 3 are laminated in this order.

[0014] The following describes the various components of the laminate in the present invention.

[0015] (1) Insulating film made of polyphenylene sulfide The insulating film made of the polyphenylene sulfide is, for example, a film mainly composed of a resin containing 85 mol% or more of para-phenylene sulfide units. From the viewpoint of heat resistance, it is preferable that the content of para-phenylene sulfide units is preferably 90 mol% or more, and more preferably 97 mol% or more. As a constituent component other than para-phenylene sulfide, a constituent containing a phenylene sulfide component is preferable. For example, meta-phenylene sulfide units, biphenylene sulfide units, biphenylene ether sulfide units, phenylene sulfone sulfide units, phenylene carbonyl sulfide units, and trifunctionalized phenylene sulfide components can be mentioned. The trifunctionalized phenylene sulfide component can be preferably used to introduce a branched chain into the molecule. Specifically, it can be mentioned that a trifunctionalized phenylene sulfide component obtained by using 1,2,4-trichlorobenzene during synthesis is introduced. The insulating film made of polyphenylene sulfide used in the laminate of the present invention is preferably manufactured, for example, by the steps shown below. The polyphenylene sulfide raw material is melted at 290 to 360 °C, formed into a film shape using a slit die, and then wound around a casting drum with a surface temperature of 20 to 70 °C and cooled and solidified to obtain an unstretched film. Subsequently, it is stretched 3.0 to 5.0 times in the longitudinal direction at 90 to 120 °C to obtain a uniaxially stretched film. Then, the uniaxially stretched film is introduced into a tenter, preheated at 90 to 120 °C, and then stretched 2.0 to 4.0 times in the width direction and heat-treated at 200 to 280 °C to obtain an insulating film made of biaxially oriented polyphenylene sulfide. Note that it is not necessarily limited to the manufacturing method shown here.

[0016] In the resin constituting the insulating film made of polyphenylene sulfide used in the laminate of the present invention, various additives, for example, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents, crosslinking agents, etc., may be added within a range that does not deteriorate their properties.

[0017] (2) Adhesive layer (2.1) Curable adhesive The adhesive layer in the present invention is heat-expandable. The heat-expandable adhesive layer can be obtained, for example, by the adhesive layer containing a foaming agent. Here, an adhesive containing a foaming agent and further being curable is a heat-expandable adhesive. In addition, as the heat-expandable adhesive, a curable adhesive generally used for the adhesive layer of a foaming adhesive sheet can be used. Examples of the curable adhesive include heat-curable adhesives and photo-curable adhesives. Among them, heat-curable adhesives are preferred. Heat-curable adhesives are applicable even when the member does not have transparency, such as in the case of a member made of metal.

[0018] In addition, examples of the curable adhesive include epoxy resin-based adhesives, acrylic resin-based adhesives, phenolic resin-based adhesives, unsaturated polyester resin-based adhesives, alkyd resin-based adhesives, urethane resin-based adhesives, thermosetting polyimide resin-based adhesives, and the like.

[0019] Among these, the curable adhesive is preferably an epoxy resin-based adhesive. That is, the curable adhesive preferably contains an epoxy resin and a curing agent. Generally, epoxy resin-based adhesives are excellent in mechanical strength, heat resistance, insulation, chemical resistance, etc., have a small curing shrinkage, and can be used in a wide range of applications. In addition, the curing agent will be described in detail below.

[0020] (2.2) Curing agent Examples of the curing agent that can be used in the present invention include curing agents generally used for epoxy resin-based adhesives. Specific examples of the curing agent include imidazole-based curing agents, phenolic curing agents, amine-based curing agents, acid anhydride-based curing agents, isocyanate-based curing agents, and thiol-based curing agents. The content of the curing agent is, for example, 1 part by mass or more and 10 parts by mass or less when the resin component contained in the adhesive layer is 100 parts by mass.

[0021] (2.3) Foaming agent The foaming agent that can be used in the present invention is generally a foaming agent used in the adhesive layer of foamed adhesive sheets. The foaming agent may be one that undergoes a foaming reaction in response to heat, or one that undergoes a foaming reaction in response to light.

[0022] The foaming initiation temperature of the foaming agent is preferably above the softening temperature of the main component of the curable adhesive such as epoxy resin, and below the activation temperature of the curing reaction of the main component of the curable adhesive such as epoxy resin. The foaming initiation temperature of the foaming agent is, for example, 70°C or higher, and may also be 100°C or higher. If the reaction initiation temperature is too low, the reaction will start too early, and foaming may occur with low flexibility and fluidity of the resin component, making it difficult to achieve uniform foaming. On the other hand, the reaction initiation temperature of the foaming agent is, for example, 210°C or lower. If the reaction initiation temperature is too high, the resin component may deteriorate.

[0023] The blowing agents mentioned above may be, for example, organic or inorganic blowing agents. Examples of organic blowing agents include azo blowing agents such as azodicarbonamide (ADCA), azobisformamide, and azobisisobutyronitrile; fluoride alkane blowing agents such as trichloromonofluoromethane; hydrazine blowing agents such as p-toluenesulfonyl hydrazide; semicarbazide blowing agents such as p-toluenesulfonyl semicarbazide; triazole blowing agents such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso blowing agents such as N,N-dinitrosoterephthalamide. On the other hand, examples of inorganic blowing agents include ammonium carbonate, ammonium bicarbonate, ammonium nitrite, ammonium borohydride, and azides. The blowing agents may be used individually or in combination of two or more.

[0024] The foaming ratio of the adhesive layer is not particularly limited, but is preferably 4 times or more, more preferably 5 times or more, and even more preferably 6 times or more. Furthermore, the foaming ratio is preferably 15 times or less, more preferably 12 times or less, and even more preferably 10 times or less. If the foaming ratio is too low, the adhesion after foaming and curing may decrease when the gap between the members is wide. Conversely, if the foaming ratio is too high, the adhesion after foaming and curing may decrease even when the gap between the members is narrow.

[0025] Here, the expansion ratio can be calculated using the following formula. Foaming ratio (times) = Thickness of adhesive layer after foaming and curing / Thickness of adhesive layer before foaming and curing The thickness of the adhesive layer before foaming is preferably 40 μm or more, more preferably 50 μm or more, and even more preferably 60 μm or more. If the adhesive layer is too thin, it may not be possible to adequately fill the gaps between the components and achieve sufficient adhesion. On the other hand, the thickness of the adhesive layer before foaming is preferably 250 μm or less, more preferably 220 μm or less, and even more preferably 200 μm or less. If the adhesive layer is too thick, the workability when winding it onto the coil wire may deteriorate.

[0026] The adhesive layer can be formed, for example, by applying an adhesive composition containing the above-mentioned curable adhesive and foaming agent, and then removing the solvent. Examples of application methods include roll coating, reverse roll coating, transfer roll coating, gravure coating, gravure reverse coating, comma coating, rod coating, blade coating, bar coating, wire bar coating, die coating, lip coating, dip coating, and the like.

[0027] The adhesive composition may or may not contain a solvent. In this specification, "solvent" has a broad meaning, including not only a strict solvent but also a dispersion medium. Furthermore, any solvent contained in the adhesive composition is removed by volatilization when the adhesive composition is applied and dried to form an adhesive layer.

[0028] Here, it is preferable that the thickness of the adhesive layer of the laminate of the present invention after foaming is 2 to 10 times the thickness of the adhesive layer before foaming. When the above ratio is 2 or more, the laminate of the present invention has better adhesive performance after foaming. On the other hand, when the above ratio is 10 or less, the laminate of the present invention becomes easier to wrap around coil wires. The above thickness of the adhesive layer after foaming refers to the thickness after the adhesive layer before foaming is treated under the following conditions, where the heating temperature is 160°C to 220°C and the heating time is 5 minutes to 30 minutes.

[0029] (3)Adhesive layer The adhesive layer of the laminate of the present invention is non-foaming. A non-foaming adhesive layer can be obtained by having the adhesive layer not contain a foaming agent, or by having it contain only a very small amount of foaming agent, as is the case with adhesive layers. If the adhesive layer contains a foaming agent, the foaming agent content is preferably 1% by mass or less of the total adhesive layer.

[0030] Conventional adhesives can be used as the non-foaming adhesives described above. Here, the heat-foaming adhesives and the non-foaming adhesives described above can be distinguished by the specific gravity of the coating film after heating under the conditions of a heating temperature of 160°C to 220°C and a heating time of 5 minutes to 30 minutes after the formation of each coating film. Examples of non-foaming adhesives include acrylic adhesives, rubber adhesives, polyester adhesives, urethane adhesives, and silicone adhesives, and among these, acrylic adhesives are preferably used in terms of transparency, light resistance, heat resistance, and heat and humidity resistance. The glass transition temperature of the resin constituting the above adhesive is preferably 0°C or lower, more preferably -10°C or lower, and particularly preferably -20°C or lower, from the viewpoint of ensuring adhesiveness. The lower limit is about -80°C.

[0031] The adhesive composition that can be used in the laminate of the present invention preferably contains a crosslinking agent. Examples of such crosslinking agents include polyisocyanate compounds, epoxy resins, melamine resins, urea resins, dialdehydes, and methylol polymers, but in the present invention, polyisocyanate compounds are preferably used. One type of crosslinking agent may be used alone, or two or more types may be used in combination. The content of the above crosslinking agent is suitable in the range of 0.01 to 20 parts by mass, and preferably in the range of 0.1 to 10 parts by mass, per 100 parts by mass of adhesive.

[0032] The method for applying the adhesive composition to obtain the adhesive layer of the present invention is not particularly limited, and conventionally known coating methods can be used. For example, coating methods such as immersion coating, spray coating, spinner coating, bead coating, wire bar coating, blade coating, roller coating, curtain coating, slot die coater, gravure coater, slit reverse coater, microgravure, and comma coater can be used.

[0033] The thickness of the adhesive layer of the present invention is suitable in the range of 5 to 100 μm, preferably in the range of 10 to 75 μm, and particularly preferably in the range of 10 to 50 μm.

[0034] The following describes the coating of the coil conductor with a laminate and the laminated structure of the coil conductor in the present invention.

[0035] (4) Method of covering coil conductors with laminate A coil conductor comprises multiple strands and a covering member. Each strand has an insulating coating on its outer surface. The core wire is a conductor and is formed in a linear shape from a conductive metal such as copper, aluminum, silver, gold, or alloys thereof. The insulating coating is formed from an insulator such as enamel resin or metal oxide.

[0036] The laminate of the present invention is wound diagonally with respect to the longitudinal direction of the coil conductor, with the adhesive layer facing the coil conductor. That is, a motor coil conductor equipped with the laminate of the present invention comprises a laminate and a coil conductor, the coil conductor is covered with one layer of the laminate, and it is preferable that the coil conductor is located on the side of the adhesive layer of the laminate. Figure 2 shows a conceptual diagram of a motor coil conductor covered with a laminate according to one embodiment of the present invention. In the conceptual diagram shown in Figure 2, the laminate 12 covers the coil conductor 11 at an angle of approximately 60 degrees with respect to the longitudinal direction (up and down direction of the paper) of the coil conductor 11. The motor coil conductor has an uncovered portion 13 and a covered portion 14. The laminates are wound without overlapping each other, and the coil conductor is covered with one layer of the laminate. Based on the above, it is preferable to employ a manufacturing method for motor coil wires that includes a step of covering the coil wires with a laminate, with the coil wires positioned on the adhesive layer side of the laminate. Furthermore, in the above motor coil wire, the coil wire is positioned on the adhesive layer side of the laminate relative to the laminate. By adopting this positional relationship, in a motor using the above motor coil wire, the insulating paper in contact with the inner wall of the motor's slot comes into contact with the foamed layer of the laminate, and the foamed adhesive layer fills the space between the insulating layer and the insulating film made of polyphenylene sulfide of the laminate, thereby firmly fixing the motor insulating coil wire inside the slot.

[0037] Furthermore, the motor coil conductor of the present invention is not limited to the embodiments described above, and various modifications and improvements are possible within the scope of the claims of this application and their equivalents.

[0038] (5) Laminated structure of motor coil conductors When multiple coil wires covering the laminate of the present invention are laminated, the structure may consist of coil wires of different sizes being laminated alternately. Here, Figure 3 shows a conceptual cross-section of a motor formed by inserting motor coil wires of different sizes into slots according to one embodiment of the present invention. In the conceptual diagram shown in Figure 3, coil wires 1 (indicated by reference numeral 21 in Figure 3) and coil wires 2 (indicated by reference numeral 22 in Figure 3) of different sizes are laminated alternately, resulting in a structure where gaps are created between adjacent coil wires. The width of these gaps is preferably 0.5 mm or more, more preferably 0.6 mm or more, and even more preferably 0.7 mm or more. If the gaps are too narrow, the adhesive layers may come into contact with each other when forming the laminated structure of the coil wires, potentially worsening workability when inserting them into the slots. On the other hand, the width of the gaps is preferably 1.0 mm or less, more preferably 0.9 mm or less, and even more preferably 0.8 mm or less. If the gaps are too wide, the foamed adhesive layer may not be able to sufficiently fill the gaps between the coil wires, potentially resulting in insufficient adhesion between the coil wires.

[0039] Next, the fabricated laminated structure is heated, causing the adhesive layer of the laminate to foam, filling the gaps between the coil wires and fixing them together. For example, the laminated structure can be heated by placing it in an oven. The oven temperature is preferably 160°C or higher, more preferably 170°C or higher, and even more preferably 180°C or higher. If the oven temperature is too low, the foaming ratio of the adhesive layer is low, and the gaps between the coil wires may not be sufficiently filled, resulting in insufficient fixing between the coil wires. On the other hand, the oven temperature is preferably 220°C or lower, more preferably 210°C or lower, and even more preferably 200°C or lower. The heating time is preferably 5 minutes or more, more preferably 7 minutes or more, and even more preferably 10 minutes or more. If the heating time is too short, the foaming ratio of the adhesive layer is low, and the gaps between the coil wires may not be sufficiently filled, resulting in insufficient fixing between the coil wires. By performing the heat treatment as described above, the adhesive layer of the laminate foams up, and the foamed adhesive layer fixes the multiple motor coil wires to each other and to the insulating paper. Furthermore, this motor includes motor coil wires, insulating paper, and slots, and the insulating paper and the multiple motor coil wires are arranged inside the slots in this order from the stator core side, and it is preferable that the spacing between the multiple motor coil wires is 0.5 mm or more and 1 mm or less.

[0040] Furthermore, the laminated structure for motor coil conductors of the present invention is not limited to the embodiments described above, and various modifications and improvements are possible within the scope of the claims of this application and their equivalents. [Examples]

[0041] [Evaluation Method] The configuration and effects of the present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. Prior to describing each example, various evaluation methods will be described.

[0042] [Measuring the film thickness of adhesive and bonding layers] The thickness of the adhesive layer formed in the form of a sticky tape was measured using a constant-pressure thickness measuring instrument (TECLOCK, PG-01J) in accordance with JIS K 7130:1999.

[0043] [Evaluation of heat-expandable adhesive layers] Adhesive was applied to PPS film adhesive tape, dried in an oven at 90°C for 10 minutes, and then heated in the oven at a set temperature of 180°C for another 10 minutes. The thickness of the adhesive layer after heat foaming was measured. Next, the foaming ratio was determined from the thickness of the adhesive layer before and after heat foaming using the aforementioned foaming ratio formula, and an adhesive layer with a foaming ratio of 1.2 or higher was defined as a heat-foaming adhesive layer.

[0044] [Evaluation of non-foaming adhesive layer] PPS film adhesive tape was dried in an oven at 90°C for 10 minutes, and then heated in the oven at a set temperature of 180°C for another 10 minutes. The thickness of the adhesive layer after heating was measured. Next, the foaming ratio of the adhesive layer was determined from the thickness of the adhesive layer before and after heating using the following formula, and an adhesive layer with a foaming ratio of less than 1.2 was defined as a non-foaming adhesive layer. The foaming ratio of the adhesive layer (times) = Thickness of the adhesive layer after heating / Thickness of the adhesive layer before heating [Sample adhesion evaluation] Regarding the laminated structure for motor coil wires of the present invention, in order to evaluate whether the adhesive layer located on the outermost surface of the laminate covering the coil wires fills the gaps between coil wires and fixes adjacent coil wires together after heat foaming, the structure was examined under a microscope (Keyence Corporation, VHX-X1) at 100x magnification. As an evaluation criterion for the state of fixation, it was determined that if there were no gaps between the foamed adhesive layers and the foamed adhesive layer was sufficiently filled, it was judged as "good," and if there were gaps between the foamed adhesive layers and they were not fixed to each other, it was judged as "not fixed."

[0045] [Example 1] (1) PPS film adhesive tape A PPS film adhesive tape was created by laminating a release film onto the adhesive layer side of a PPS film adhesive tape (manufactured by Teraoka Seisakusho Co., Ltd., film thickness 25 μm, adhesive layer thickness 15 μm), which is an insulating film (PPS film) made of polyphenylene sulfide with an adhesive layer applied to the back surface.

[0046] (2) Formation of the adhesive layer An adhesive composition (ThreeBond 2280H, manufactured by ThreeBond Corporation, with a solid content of 75%) was applied to the side of the PPS film adhesive tape opposite to the release film using an applicator, so that the thickness after coating was 80 μm. Then, it was dried in an oven at 90°C for 10 minutes to form an adhesive layer.

[0047] (3) Wrapping the laminate around the coil wire After cutting the laminate with the adhesive layer into strips 10 mm wide and 150 mm long, the release film on the adhesive side was peeled off, and as shown in Figure 2, with the adhesive side facing the coil wire, the laminate was spirally wrapped around a coil wire 9 mm wide and 70 mm long, ensuring that the laminate itself did not overlap. The laminate covered 50 mm along the length of the coil wire, leaving the remaining 20 mm uncovered.

[0048] (4) Laminated structure of coil conductors For the coil wires wound around the laminate, multiple films were inserted to adjust the spacing between the uncovered portions so that the gap was 0.7 mm. Three coil wires 1 and two coil wires 2 were then superimposed as shown in Figure 3, and the uncovered portions were secured with heat-resistant tape to create a laminated structure in which the coil wires maintained the above-mentioned spacing. Next, the fabricated laminated structure was inserted, with the portion wound around the laminate at the front, into a glass case that mimicked the inside of a stator slot, with an opening cross-section of 10 mm in width, 20 mm in length, and 45 mm in depth, as shown in Figure 4. Furthermore, a film simulating insulating paper was inserted into the gap between the glass case and the laminated structure, and the gap between the inserted film and the laminated structure was adjusted to 200 μm.

[0049] (5) Fixation between coil wires due to heating and foaming A glass case containing the aforementioned laminated structure was heated in an oven at a set temperature of 180°C for 10 minutes to prepare an evaluation sample of the foamed adhesive layer.

[0050] [Example 2] An evaluation sample was prepared in the same manner as in Example 1, except that the adhesive layer was applied so that its thickness after coating was 100 μm.

[0051] [Example 3] An evaluation sample was prepared in the same manner as in Example 1, except that the adhesive layer was applied so that its thickness after coating was 60 μm.

[0052] [Example 4] An evaluation sample of the foamed adhesive layer was prepared in the same manner as in Example 1, except that the glass case into which the laminated structure was inserted was heated in an oven at a set temperature of 180°C for 30 minutes.

[0053] [Example 5] An evaluation sample of the foamed adhesive layer was prepared in the same manner as in Example 1, except that the spacing between the coil wires was set to 0.8 mm when laminating the coil wires.

[0054] [Comparative Example 1] An evaluation sample was prepared in the same manner as in Example 1, except that the adhesive layer was applied so that its thickness after coating was 30 μm.

[0055] [Comparative Example 2] An evaluation sample was prepared in the same manner as in Example 1, except that the glass case into which the laminated structure was inserted was heated in an oven at a set temperature of 140°C for 10 minutes.

[0056] [Comparative Example 3] An evaluation sample was prepared in the same manner as in Example 1, except that the glass case into which the laminated structure was inserted was heated in an oven at a set temperature of 150°C for 10 minutes.

[0057] [evaluation] The adhesion state between coil conductors and between the coil conductors and the film simulating insulating paper was evaluated for the samples prepared as described above. The contents of the prepared samples and the evaluation results are shown in Tables 1 and 2.

[0058] [Table 1]

[0059] [Table 2]

[0060] From the above results, in the embodiment of the present invention, the adhesive layer on the outermost surface of the laminate wound around the coil wire expands due to heating and foaming, filling the gaps between adjacent coil wires and allowing them to be fixed together. Similarly, the gaps between the coil wire and the film simulating insulating paper are also filled by the heated and foamed adhesive layer, allowing them to be fixed together. From the embodiment of the present invention, a laminate can be obtained that satisfies the fixing of multiple motor coil wires to each other and between motor coil wires and insulating paper within the slots of a motor stator.

[0061] On the other hand, in the comparative example, if the thickness of the adhesive layer after coating is thin, the thickness of the adhesive layer after heat foaming is not sufficient to fill the gaps between the coil wires, and the coil wires cannot be fixed together. Also, if the heating temperature when foaming the adhesive layer is low, the foaming ratio of the adhesive layer will be low, so the thickness of the adhesive layer after heat foaming may not be sufficient to fill the gaps between the coil wires, and it may not be possible to reliably fix the coil wires together. [Industrial applicability]

[0062] According to the present invention, even when there are gaps between the coil conductors in the motor stator, it is possible to manufacture a motor stator in which the coil conductors are fixed together and the stator core, insulating paper, and coils are more securely fixed. [Explanation of symbols]

[0063] 1: Adhesive layer, 2: PPS film, 3: Adhesive layer, 11: Coil wire, 12: Laminate, 21: Coil wire 1, 22: Coil wire 2, 23: Insulating paper (film), 31: Glass case, 32: Opening, 33: Adjustment film

Claims

1. A laminate comprising, in this order, an adhesive layer, an insulating film made of polyphenylene sulfide, and an adhesive layer, wherein the adhesive layer is heat-foaming and the adhesive layer is non-foaming.

2. The laminate according to claim 1, wherein the thickness of the adhesive layer before foaming is 40 μm or more and 200 μm or less.

3. The laminate according to claim 1, wherein the thickness of the adhesive layer after foaming is 2 times or more and 10 times or less than the thickness of the adhesive layer before foaming.

4. A motor coil conductor comprising a laminate and a coil conductor as described in claim 1, wherein the coil conductor is covered with one layer of the laminate, and the coil conductor is located on the side of the adhesive layer of the laminate with respect to the laminate.

5. A motor comprising the motor coil wires, insulating paper, and slots described in claim 4, wherein the insulating paper and a plurality of the motor coil wires are arranged inside the slots in this order from the stator core side, the spacing between the plurality of motor coil wires is 0.5 mm or more and 1 mm or less, and the plurality of motor coil wires and the motor coil wires and insulating paper are fixed by the foamed adhesive layer.

6. A method for manufacturing a motor coil conductor according to claim 4, characterized in that it includes a step of covering the coil conductor with the laminate described in claim 1, with the coil conductor positioned on the adhesive layer side of the laminate.

7. A method for manufacturing a motor according to claim 5, characterized by comprising the steps of arranging the motor coil wires and the insulating paper described in claim 4 in that order from the stator core side, and arranging a plurality of the motor coil wires at intervals of 0.5 mm or more and 1 mm or less.

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