JP2007312580A - Manufacturing method of resin-mold stator, and the resin-mold stator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method, capable of manufacturing a resin mold stator that is superior in various characteristics, such as thermal conductivity, heat radiation performance, crack resistance and heat resistance, by making a molded resin composition permeate into between stator windings, even if a resin mold stator, has high occupation rate for a stator wiring in a slot. <P>SOLUTION: The manufacturing method of the resin mold stator has a step of executing wiring processing of winding an insulation-coated stator wiring of dimensions of not larger than 2.0 mm around a stator core so that the occupation rate of in the slot is not less than 70%; a step of arranging the stator core, provided with the sator winding in a die; and a step of molding the molded resin composition, while pressurizing and supplying it into the die by a pressurizing gelling method to form the resin-molded stator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin molded stator manufacturing method and a resin molded stator, and more particularly to a resin molded stator manufacturing method and a resin molded stator that are suitably used as a stator for a hybrid electric vehicle motor.

  With the demand for energy saving and resource saving in industrial equipment, home appliances, automobiles, etc., there is a demand for higher efficiency, smaller size and lighter motors for driving these products. In particular, motors in electric vehicles and hybrid electric vehicles are required to have high efficiency and small size and light weight as well as improved fuel efficiency aimed at protecting the global environment, as well as being installed in a limited mounting space.

  Under such circumstances, improvement of thermal conductivity, heat dissipation, crack resistance, and heat resistance is desired for improvement in reliability, particularly for problems caused by generated heat. Further, with the rapid spread of hybrid electric vehicles and the like, there is a strong demand for shortening the manufacturing process of motors used, improving productivity, and reducing manufacturing costs.

  A stator winding provided in the stator of such a motor is generally varnish-insulated to protect it. In addition to the electrical insulation of the stator windings, the varnish insulation treatment provides the stator with functions such as physical support, pinhole and machining flaw coating, and heat transfer to the stator core.

  As the insulating varnish used for the varnish insulation treatment, an unsaturated polyester resin or an epoxy resin is usually used. And the varnish insulation process is performed by impregnating an insulation varnish by the immersion impregnation (dipping) method or the dripping impregnation (drip) method (for example, refer patent document 1). Moreover, in order to improve thermal conductivity, the thing containing fillers, such as an alumina, is used as an insulating varnish (for example, refer patent document 2).

On the other hand, in a small motor or the like, a stator core provided with stator windings is placed in a mold, and then a mold resin composition is injected into the mold to integrate the stator core and the stator windings. (For example, refer to Patent Documents 3 and 4).
JP 2005-285933 A Japanese Patent Laid-Open No. 2003-244907 JP-A-8-182271 JP-A-10-243595

  As described above, in the conventional stator, the stator winding is impregnated with the insulating varnish by the immersion impregnation method or the dropping impregnation method, or the stator core provided with the stator winding is disposed in the die, It is manufactured by injecting a mold resin composition.

  However, as for the method of impregnating the insulating varnish by the conventional immersion impregnation method or the drop impregnation method, if the space factor of the stator winding in the slot becomes high, the insulating varnish cannot be sufficiently impregnated, and heat dissipation is ensured. It becomes difficult. In addition, since the insulating varnish adheres to unnecessary portions of the stator, a trimming process for removing the adhered insulating varnish is required, and the manufacturing process of the stator increases and the manufacturing cost increases.

  As for the method of injecting the mold resin composition into the mold, an unsaturated polyester resin, an epoxy resin, or the like that is solid at room temperature used for a so-called molding material is used as the mold resin composition. However, it is difficult to sufficiently penetrate between the stator windings, and it is difficult to improve various characteristics including heat dissipation. In particular, in order to achieve a small size and high efficiency, for the case where the space factor of the stator winding in the slot is increased, such a decrease in the permeability of the mold resin composition becomes remarkable, and heat dissipation is started. It is difficult to improve various characteristics.

  The present invention has been made to solve the above-described problems, and even when a resin-molded stator having a high space factor of the stator windings is manufactured, a mold resin is interposed between the stator windings. It is an object of the present invention to provide a production method capable of producing a resin molded stator that can sufficiently infiltrate the composition and is excellent in various properties such as heat dissipation, crack resistance, and heat resistance.

  Moreover, even if the present invention is a resin-molded stator having a high space factor of the stator windings, the mold resin composition is sufficiently permeated between the stator windings, and heat dissipation, crack resistance, heat resistance, etc. An object of the present invention is to provide a resin-molded stator excellent in various characteristics.

  The method of manufacturing the resin-molded stator of the present invention includes a step of winding a stator winding having a diameter of 2.0 mm or less having an insulating coating on the stator core so that the space factor in the slots of the stator core is 70% or more, A step of disposing a stator core provided with the stator winding in a mold; and a step of forming a resin mold stator by pressurizing a mold resin composition into the mold by a pressure gelation method; It is characterized by having.

  In the method for producing a resin-molded stator of the present invention, the mold resin composition is (a) an epoxy resin having more than one epoxy group per molecule, (b) an acid anhydride curing agent, and (c) a filler. The viscosity at 140 ° C. is 0.005 Pa · s or more and 2.0 Pa · s or less, the curing time at 140 ° C. is 60 seconds or more and 300 seconds or less, and the thermal conductivity of the cured product is It is preferably 0.5 W / m · K or more.

  In the mold resin composition, the (a) epoxy resin having more than one epoxy group per molecule contains an alicyclic epoxy resin, and the (c) filler has an average particle size of 3 μm or more, It is preferable to contain at least one selected from spherical silica, alumina, magnesia, boron nitride, aluminum nitride and silicon nitride of 30 μm or less.

  In addition, in the molding by the pressure gelation method, the injection pressure when pressurizing and replenishing the mold resin composition is 0.3 MPa or more and 1.0 MPa or less, and the molding time is 10 minutes or more and 30 minutes or less. Is preferred.

  The resin-molded stator of the present invention includes a stator core, a stator winding having a diameter of 2.0 mm or less having an insulation coating wound in a slot of the stator core with a space factor of 70% or more, the stator core, and the stator winding A mold resin composition provided so as to cover the wire, and the mold resin composition provided so as to cover the stator core and the stator winding is provided by a pressure gelation method. It is characterized by being.

  According to the present invention, by producing a resin-molded stator using a pressure gelation method, a stator winding having a diameter of 2.0 mm or less in a slot of the stator has a high space factor of 70% or more. Even if it is provided, the mold resin composition can be sufficiently infiltrated between the stator windings and is excellent in various properties such as thermal conductivity, heat dissipation, crack resistance and heat resistance. A resin molded stator can be manufactured.

  Further, according to the present invention, since the resin-molded stator is manufactured using the pressure gelation method, the insulating varnish does not adhere to unnecessary portions as in the conventional drop impregnation method. Can be omitted, the workability in manufacturing the stator can be improved, and the manufacturing cost of the stator can be reduced.

Hereinafter, the present invention will be described in detail.
The method for producing a resin-molded stator of the present invention includes a step of winding a stator winding having a diameter of 2.0 mm or less having an insulating coating on the stator core so that the space factor in the slots of the stator core is 70% or more (hereinafter referred to as “winding process”). , Called a winding step), a step of arranging the stator core provided with the stator winding in the mold (hereinafter referred to as an arrangement step), and a mold in the die by the pressure gelation method. A step of forming the resin composition by pressurizing the resin composition to form a resin molded stator (hereinafter referred to as a molding step).

  In the method for producing a resin-molded stator of the present invention, a stator core having an insulation coating is pre-wound into a stator core by performing molding while replenishing a mold resin composition by a pressure gelation method, Even when a stator winding having a diameter of 2.0 mm or less is wound with a high space factor of 70% or more in the slot, a mold resin composition is used between the stator windings. It can be effectively infiltrated, and a resin molded stator excellent in various properties such as thermal conductivity, heat dissipation, crack resistance, and heat resistance can be obtained.

  Here, the pressure gelation method means that a mold is set to a mold resin composition, for example, a curable epoxy resin composition at a sufficiently high temperature to start thermosetting, and the mold resin composition is placed in the mold. The mold resin composition is gradually cured by injecting the mold resin composition, and the mold resin composition is further added from the outside of the mold into the mold so as to compensate for the reduction (volume reduction) accompanying the curing of the mold resin composition. It is a method of continuing to replenish pressure.

  Hereafter, the manufacturing method of the resin mold stator of this invention is demonstrated concretely. FIG. 1 shows a specific example of the molding step. The mold 1 includes, for example, a fixed mold 1a, a split mold 1b, and a movable mold 1c. The mold 1 is provided with a gate port 1d for injecting a mold resin composition.

  In the mold 1, for example, a stator core 4 in which a stator winding 3 is wound through a bobbin 2 is disposed. The stator core 4 having the stator winding 3 is previously wound outside the mold 1 by a winding process, and is placed in the mold 1 by a subsequent placement process. Here, the stator winding 3 has an insulation coating and has a diameter of 2.0 mm or less. The stator winding 3 is wound so that the space factor in the slots of the stator core 4 is 70% or more. In addition, as the stator core 4 provided with such a stator winding 3, the one manufactured by a known manufacturing method can be used.

  The mold 1 in which the stator core 4 having the stator winding 3 is arranged in this manner is sufficient for the mold resin composition to start thermosetting by a heating device (not shown) provided in the mold 1. Heat to high temperature. At this time, if the mold 1 has the gate opening 1d side as the mold lower part 1B and the part far from the gate opening 1d side as the mold upper part 1U, the temperature of the mold upper part 1U becomes higher than the mold lower part 1B. The mold 1 may be heated.

  For example, an injection nozzle 11 connected via a transport line 10 to a storage device or storage tank (not shown) in which a molding resin composition for injection is stored is connected to the gate port 1d of the mold 1, and this injection A mold resin composition is injected into the mold 1 from the nozzle 11. The mold resin composition injected from the gate port 1d flows, for example, into the mold 1 in the direction indicated by the arrow, and is sequentially injected into each space in the mold 1 and provided in the stator core 4. It also penetrates between the stator windings 3.

  The mold resin composition injected into the mold 1 starts to be cured, for example, from the upper part 1U of the mold. At this time, the mold resin composition is continuously pressurized and supplied from the injection nozzle 11 into the mold 1 so as to compensate for the reduction due to the hardening of the mold resin composition injected into the mold 1. And the pressurization replenishment of a mold resin composition is stopped in the stage which gelatinization of the mold resin composition was complete | finished. Thereafter, if necessary, post-curing (secondary curing) or the like is performed to complete the curing to obtain a resin-molded stator.

  The injection pressure when pressurizing and replenishing the mold resin composition by the pressure gelation method as described above is preferably 0.3 MPa or more and 1.0 MPa or less. Moreover, it is preferable that the shaping | molding time of shaping | molding by the above-mentioned pressure gelation method shall be 10 minutes or more and 30 minutes or less.

  When the injection pressure is less than 0.3 MPa, the mold resin composition is not sufficiently replenished, and defects such as cracks, nests, and voids are likely to occur. In addition, after injecting the mold resin composition into the mold 1, it is in a liquid state, a gelled state in which the curing progresses to some extent from this liquid state, and a state in which toughness at the final stage of curing is further imparted. However, when the injection pressure exceeds 1.0 MPa, cracks are likely to occur at the boundary portions of various cured states.

  Further, although slightly different depending on the mold resin composition to be used, if the molding time is less than 10 minutes, the mold resin composition may be insufficiently cured, and if the molding time is about 30 minutes, sufficient curing is achieved. If it exceeds that, it is not preferable because the productivity is impaired.

  Further, in such a pressure gelation method, the injection pressure when the mold resin composition is pressurized and replenished is reduced according to the progress of the curing reaction of the mold resin composition injected into the mold 1. It is preferable. That is, the injection pressure when replenishing the pressure is relatively high until the weak point where defects such as cracks, nests, and voids tend to occur structurally or in shape from the liquid state to the gelled state. It is preferable to change the injection pressure at the time of replenishing the pressure so as not to cause an internal defect in a stepwise manner so as to be relatively low.

  By doing in this way, generation | occurrence | production of the defects, such as a crack, a nest, and a void, can be suppressed in the weak part which a defect, such as a crack, a nest, and a void tends to generate | occur | produce structurally or in shape. In particular, in the case of a complicated shape in which the stator winding 3 is provided on the stator core 4 as in the present invention, there are many weak points where defects such as cracks, nests and voids are likely to occur structurally or in shape. However, it is possible to effectively suppress the occurrence of defects such as cracks, nests, and voids in the weak points by gradually changing the injection pressure at the time of replenishing pressure as described above.

  When changing the injection pressure when pressurizing and replenishing the mold resin composition, for example, 0.5 MPa until the mold resin composition around the stator core 4 having the mold upper part 1U and the stator winding 3 is in a gelled state. Pressurization and replenishment were performed at the injection pressure, and the mold resin composition in the vicinity of the gate port 1d was held at an injection pressure of 0.5 MPa until it became a gelled state. Finally, the vicinity of the gate port 1d became a gelled state. The method of releasing the injection pressure of pressurization supply at the time is mentioned. By doing in this way, it can suppress more effectively that defects, such as a crack, a nest, and a void, generate in a resin mold stator.

  Suitable mold resin compositions for use in the present invention include, for example, (a) an epoxy resin having more than one epoxy group per molecule, (b) an acid anhydride curing agent and (c) a filler. It is mentioned as a thing.

  (A) As an epoxy resin having more than one epoxy group per molecule, the molecular weight, molecular structure, etc. are not necessarily limited as long as the epoxy resin has more than one epoxy group per molecule. A known epoxy resin can be used, but a liquid that is liquid at room temperature is preferably used because of the impregnation of the stator winding 3.

  Specific epoxy resins include, for example, aromatic epoxy resins such as bisphenol type, novolac type, and biphenol type, and alicyclic epoxy resins obtained by epoxidation of cyclohexane derivatives and the like. They can be used in combination. In particular, from the viewpoint of improving the heat resistance and moisture resistance of the resin molded stator to be produced, it is preferable to contain an alicyclic epoxy resin.

  (B) Any acid anhydride curing agent having an acid anhydride curing agent group in the molecule can be used without particular limitation, as long as it has an acid anhydride curing agent group in the molecule. Specific examples of the acid anhydride curing agent include hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride and the like, and these can be used alone or in combination of two or more. (B) The content of the acid anhydride curing agent is preferably 80 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the epoxy resin as the component (a).

  (C) As a filler, what is generally used as a filler of an epoxy resin composition can be used without a restriction | limiting in particular. Specific examples of the filler include silica such as crystalline silica and fused silica, metal oxides such as alumina and magnesia, metal hydrates such as aluminum hydroxide and magnesium hydroxide, aluminum nitride, boron nitride, and silicon nitride. These nitrides can be used, and these can be used alone or in admixture of two or more.

  In the present invention, from the viewpoint of improving the thermal conductivity of the cured product of the mold resin composition and improving the heat dissipation of the resin mold stator, etc., from silica, alumina, magnesia, boron nitride, aluminum nitride, boron nitride and silicon nitride. It is preferable to contain at least one selected from the high thermal conductive fillers to be contained in the mold resin composition.

Moreover, in order to maintain the moldability of the mold resin composition, the filler is preferably spherical. Furthermore, from the viewpoint of maintaining the moldability of the mold resin composition and the thermal conductivity of the cured product, the filler preferably has an average particle diameter (D ₅₀ ) of 3 μm or more and 30 μm or less. The average particle size is measured by, for example, a laser diffraction method, and indicates the size of particles that are accumulated from a low particle size and reach 50% by volume.

  (C) The filler content is preferably determined in consideration of the balance between the moldability of the mold resin composition and the thermal conductivity of the cured product. For example, the thermal conductivity of the cured product is 0.5 W / m · The content is preferably adjusted so as to be K or more. Specifically, the filler (c) is preferably 100 parts by mass or more and 1000 parts by mass or less with respect to 100 parts by mass of the epoxy resin as the component (a). (C) If the content of the filler is less than 100 parts by mass, the thermal conductivity of the cured product may be insufficient, and the mechanical strength, heat resistance, moisture resistance and the like may not be sufficient. On the other hand, when the content of the filler (c) exceeds 1000 parts by mass, the viscosity of the mold resin composition increases and the moldability may not be sufficient.

  In addition to the components (a) to (c) as described above, the mold resin composition used in the present invention includes, for example, a curing accelerator and a coupling agent as necessary and within the limits of the present invention. , Various additives such as a leveling agent, an antifoaming agent, a stress relaxation agent, and a pigment can be contained.

  Any curing accelerator can be used without particular limitation as long as it has a function of promoting the curing reaction between the epoxy resin of component (a) and the acid anhydride curing agent of component (b). -Imidazole compounds such as ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1,8-diazabicyclo [5,4,0] undecene-7 And tertiary amines such as (DBU) and benzyldimethylamine (BDMA). When a curing accelerator is contained, for example, it is contained so as to be 0.3 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the epoxy resin as the component (a).

  The mold resin composition used in the present invention is prepared by sufficiently mixing, for example, the epoxy resin of component (a) and the filler of component (c) as a main component, and separately, an acid anhydride curing agent and curing of component (b). It can be prepared by thoroughly mixing accelerators or the like to form a curing agent component, and uniformly mixing these main component and curing agent component.

  The mold resin composition obtained by mixing such a main ingredient component and a curing agent component preferably has a viscosity at 140 ° C. of 0.005 Pa · s or more and 2.0 Pa · s or less, and 140 ° C. The curing time is preferably 60 seconds or more and 300 seconds or less.

  If the viscosity of the molding resin composition is less than the above lower limit value, the amount of adhesion to the stator winding 3 or the stator core 4 may be insufficient, and if it exceeds the above upper limit value, penetration between the stator windings 3 may occur. This is not preferable because the property may be lowered. The viscosity of the mold resin composition is measured according to JIS C2105.

  Further, if the curing time of the mold resin composition is less than the above lower limit value, there is a possibility that the filling property to voids generated in the mold 1 during the molding process may not be sufficient, and if the above upper limit value is exceeded, The molding time including post-curing (secondary curing) becomes long, which may reduce productivity, which is not preferable. In addition, the measurement of the curing time of the mold resin composition is performed by measuring the curing time at 140 ° C. by a test tube method.

  Moreover, as above-mentioned, it is preferable that the mold resin composition is prepared so that the heat conductivity of hardened | cured material may be 0.5 W / m * K or more. If the heat conductivity of the cured product of the mold resin composition is less than the above heat conductivity, the heat dissipation of the resin mold stator cannot be sufficiently improved, and the reliability may not be sufficiently improved. is there.

  Hereinafter, the present invention will be described in more detail with reference to examples. Below, manufacture of the resin composition used by the Example and the comparative example is demonstrated first.

(Resin composition 1)
70 parts by mass of a bisphenol A diglycidyl ether type epoxy resin (made by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 828, liquid (normal temperature)), alicyclic epoxy resin (produced by Daicel Chemical Industries, trade name: CEL2021A, liquid (normal temperature) ) 30 parts by mass, crushed fused silica (manufactured by Tatsumori Co., Ltd., trade name: RD-8, average particle size (D ₅₀ ) 15 μm), 300 parts by mass, spherical fused silica (manufactured by Denka Co., Ltd., trade name: FB950, average particle size) (D ₅₀ ) 25 μm) 400 parts by mass, spherical aluminum nitride (manufactured by Matsuo Sangyo Co., Ltd., trade name: FAN-f05, average particle size (D ₅₀ ) 5 μm), 100 parts by mass, antifoaming agent (manufactured by Toshiba Silicone Co., Ltd., trade name) TSA720) 0.1 part by mass, silane coupling agent (manufactured by Nihon Unicar Co., Ltd., trade name: A-187) 0.5 part by mass at 80 ° C. for 1 hour under vacuum kneading, main agent It was and minutes. Further, 100 parts by mass of methyltetrahydrophthalic anhydride and 1.8 parts by mass of 2-ethyl-4-methylimidazole as a curing accelerator were mixed to obtain a curing agent component. And the resin composition 1 (mold resin composition) was manufactured by mixing these main ingredient components and curing agent components uniformly.

(Resin composition 2)
70 parts by mass of a bisphenol A diglycidyl ether type epoxy resin (made by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 828, liquid (normal temperature)), alicyclic epoxy resin (produced by Daicel Chemical Industries, trade name: CEL2021A, liquid (normal temperature) ) 30 parts by weight, spherical fused silica (Denka Co., Ltd., trade name: FB950, average particle size _(D 50) 25 [mu] m) 60 parts by mass, antifoaming agent (Toshiba silicone Co., Ltd., trade name TSA720) 0.1 parts by weight, 0.5 parts by mass of a silane coupling agent (trade name: A-187 manufactured by Nihon Unicar Co., Ltd.) was vacuum kneaded at 80 ° C. for 1 hour to obtain a main component. Further, 100 parts by mass of methyltetrahydrophthalic anhydride and 1.8 parts by mass of 2-ethyl-4-methylimidazole as a curing accelerator were mixed to obtain a curing agent component. And the resin composition 2 (mold resin composition) was manufactured by mixing these main ingredient components and curing agent components uniformly.

(Resin composition 3)
70 parts by mass of a bisphenol A diglycidyl ether type epoxy resin (made by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 828, liquid (normal temperature)), alicyclic epoxy resin (produced by Daicel Chemical Industries, trade name: CEL2021A, liquid (normal temperature) ) 30 parts by mass, crushed fused silica (manufactured by Tatsumori Co., Ltd., trade name: RD-8, average particle size (D ₅₀ ) 15 μm), 300 parts by mass, spherical fused silica (manufactured by Denka Co., Ltd., trade name: FB942, average particle size) (D ₅₀ ) 16 μm) 700 parts by mass, spherical aluminum nitride (manufactured by Matsuo Sangyo Co., Ltd., trade name: FAN-f05, average particle size (D ₅₀ ) 5 μm), 100 parts by mass, antifoaming agent (manufactured by Toshiba Silicone Co., Ltd., trade name) TSA720) 0.1 part by mass, silane coupling agent (manufactured by Nihon Unicar Co., Ltd., trade name: A-187) 0.5 part by mass at 80 ° C. for 1 hour under vacuum kneading, main agent It was and minutes. Further, 100 parts by mass of methyltetrahydrophthalic anhydride and 1.8 parts by mass of 2-ethyl-4-methylimidazole as a curing accelerator were mixed to obtain a curing agent component. And the resin composition 3 (mold resin composition) was manufactured by mixing these main ingredient components and curing agent components uniformly.

  In Table 1, the composition of the resin compositions 1-3 is shown collectively. In addition, the unit of the numerical value in a table | surface is a mass part. Table 2 shows the viscosity of the resin compositions 1 to 3 at 140 ° C., the curing time at 140 ° C., and the thermal conductivity of the cured product. In Table 2, unsaturated polyester resin for molding material (trade name: AP214, manufactured by Kyocera Chemical Co., Ltd.) and polyester varnish for impregnation treatment (trade name: TVB2122, manufactured by Kyocera Chemical Co., Ltd.) used in Examples described later are used. The characteristics are shown together.

  Here, the viscosity of the resin composition was measured according to JIS C2105. Further, the curing time of the resin composition was measured by a test tube method. Furthermore, the thermal conductivity when the resin composition was used as a cured product was measured by a laser flash method at a measurement temperature of 25 ° C. using Rigaku LF / TCM-FA8510B.

Example 1
A stator core having an insulating coating was wound on the stator core via a bobbin to produce a stator core with a stator coil. Note that the stator winding having an insulation coating had a diameter of 0.8 mm, and the space factor of the stator winding in the stator core slot was set to 70%. Moreover, the mass of the whole stator core with a stator winding manufactured was 20 kgf.

Next, a stator core with stator windings was placed in a mold as shown in FIG. 1, and the entire mold was heated to 160 ° C. On the other hand, the resin composition 1 produced in advance was heated to 60 to 80 ° C., stirred, and sufficiently deaerated. And the resin composition 1 in which this deaeration was performed was inject | poured in the metal mold | die, and it shape | molded by the pressure gelation method. In the molding by the pressure gelation method, the molding time was 20 minutes, and the injection pressure when the resin composition 1 was replenished with pressure was 10 kgf / cm ² (0.98 MPa). Thereafter, the molded product was taken out from the mold and post-cured for 6 hours in a high-temperature bath at 160 ° C. to produce a resin-molded stator.

(Example 2)
A resin molded stator was manufactured in the same manner as in Example 1 except that the resin composition 2 was used.

(Example 3)
A resin molded stator was manufactured in the same manner as in Example 1 except that the resin composition 3 was used.

Example 4
A resin-molded stator was produced in the same manner as in Example 1 except that a commercially available unsaturated polyester resin for molding material (trade name: AP214, manufactured by Kyocera Chemical Co., Ltd.) was used as the resin composition.

(Comparative Example 1)
Using a stator core with a stator winding similar to that in Example 1, using a commercially available polyester-based impregnation varnish (Kyocera Chemical Co., Ltd., trade name: TVB2122), impregnation and curing treatment were performed by a dipping impregnation method to produce a stator. did. For Comparative Example 1, a trimming step for removing the insulating varnish adhering to unnecessary portions was performed.

(Comparative Example 2)
Using a stator core with a stator winding similar to that in Example 1 and the resin composition 1, instead of molding by the pressure gelation method, molding was performed by a conventional vacuum casting method to produce a resin-molded stator.

  Next, with respect to the stators manufactured in Examples and Comparative Examples, the stator appearance was evaluated and the filling rate of the resin (resin composition) in the stator slots was measured. Moreover, about the stator manufactured by the Example and the comparative example, while measuring the temperature rise of a stator, evaluation of crack resistance was performed. The results are shown in Table 3.

  In addition, the appearance of the stator was evaluated by visually observing the appearance of the stator. If there was a sink, it was indicated as “x” in the table, and if there was no sink, it was determined as “good”. It showed in. The resin (resin composition) filling rate in the stator slot is measured by cutting the stator slot and measuring the area filled with the resin (resin composition). Relative evaluation was made assuming that the area when completely filled was 100%.

  The stator temperature was increased by energizing the stator at 20 ° C. for 2 hours, measuring the surface temperature of the stator immediately after energization with a surface thermometer, and taking the difference from the surface temperature of the stator before energization. The crack resistance of the stator was determined by visually observing the appearance of the stator after 1000 cycles, with the operation of leaving the stator at -40 ° C. for 30 minutes and then leaving it at 125 ° C. for 30 minutes as one cycle. In the table, the evaluation is indicated by “◯” as the crack resistance is good if no crack is observed, and indicated by “△” if the crack is slightly observed. What occurred was indicated by "x".

  As apparent from Table 3, in the stator of Example 1 and the stator of Comparative Example 2 using the same resin composition 1, the stator of Example 1 by the pressure gelation method is superior in stator appearance, It was confirmed that the temperature rise of the stator was also suppressed.

  For example, as is apparent from the results of the stators of Examples 1 to 3, the resin composition having a viscosity at 140 ° C. in the range of 0.005 Pa · s to 2.0 Pa · s is used. It was confirmed that the filling rate in the slot was sufficient. Further, it was recognized that a stator having an excellent appearance and the like can be produced without reducing productivity by using a resin composition having a curing time at 140 ° C. in the range of 60 seconds to 300 seconds. . Furthermore, it was recognized that the temperature rise of the stator can be effectively suppressed by using a resin composition having a cured product with a thermal conductivity of 0.5 W / m · K or more.

Sectional drawing which shows an example of the shaping | molding process of this invention typically.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Mold, 1a ... Fixed mold, 1b ... Split mold, 1c ... Movable mold, 1d ... Gate opening, 2 ... Bobbin, 3 ... Stator winding, 4 ... Stator core, 1B ... Lower mold part, 1U ... Upper part of mold, 10 ... transport line, 11 ... injection nozzle

Claims (5)

Winding a stator winding having a diameter of 2.0 mm or less having an insulating coating so that the space factor in the slots of the stator core is 70% or more;
Disposing a stator core provided with the stator winding in a mold;
And a step of forming a resin mold stator by pressurizing and replenishing the mold resin composition into the mold by a pressure gelation method.   The mold resin composition contains (a) an epoxy resin having more than one epoxy group per molecule, (b) an acid anhydride curing agent, and (c) a filler, and is at 140 ° C. Viscosity of 0.005 Pa · s or more and 2.0 Pa · s or less, curing time at 140 ° C. is 60 seconds or more and 300 seconds or less, and the thermal conductivity of the cured product is 0.5 W / m · K or more. The method of manufacturing a resin molded stator according to claim 1.   The (a) epoxy resin having more than one epoxy group per molecule contains an alicyclic epoxy resin, and the (c) filler is spherical silica having a mean particle size of 3 μm or more and 30 μm or less, alumina, The method for producing a resin-molded stator according to claim 2, comprising at least one selected from magnesia, boron nitride, aluminum nitride, and silicon nitride.   The molding by the pressure gelation method is characterized in that an injection pressure when pressurizing the mold resin composition is 0.3 MPa or more and 1.0 MPa or less, and a molding time is 10 minutes or more and 30 minutes or less. A method for manufacturing a resin-molded stator according to any one of claims 1 to 3. A stator core, a stator winding having a diameter of 2.0 mm or less having an insulation coating wound in a slot of the stator core with a space factor of 70% or more, and the stator core and the stator winding are provided. A resin molded stator having a molded resin composition,
A resin-molded stator, wherein a molded resin composition provided so as to cover the stator core and the stator windings is provided by a pressure gelation method.

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