Stator and method for manufacturing the stator

Abstract

Stator (10) comprising: a stator core (11) in which a coil strand (13) is wound around each of a plurality of tooth regions (11b) formed as an annular yoke region (11a); an annular plate (15) located at a point where it overlaps an annular region of the stator core (11) in a direction along an axial center X of the stator core (11); a plurality of terminals (16) supported by the plate (15) to which end regions (13a) of a plurality of coil strands (13) extending from the stator core (11) are each connected;and a resin (17) enclosing the stator core (11) and the plate (15) in a state in which part of the plurality of terminals (16) is exposed, in which a plurality of engagement retention areas (15a) corresponding to the plurality of terminals (16) are formed in the plate (15) on a side facing away from the stator core (11), and each of the terminals (16) has a flat base area (16a) that fits into one of the engagement retention areas (15a), a coil connection area (16b) that projects upwards in a perpendicular direction from the base area (16a) and is connected to the end area (13a) of a coil strand (13), and a printed circuit board connection area (16c) that projects towards the side of the plate (15) facing away from the stator core (11) and is exposed by the resin (17).

Description

TECHNICAL FIELDThis disclosure relates to a resin stator and a method of manufacturing the stator.BACKGROUND ARTFor a stator having the above-described configuration, a technique is known in which a stator core is formed in which a coil strand is wound around a tooth portion of an annular core, the stator core is inserted into resin to produce a stator in a state in which an end portion of each coil strand is pulled out from a hollow portion of an annular plate located on an end surface of the stator core, as disclosed in JP 2016-82 643 A1. U.S. Pat. No. 2015 / 0 076 943 A1, JP H08-79 999 A and CN 1 04 767 295 A disclose further stators.In the technique disclosed in JP 2016-82 643 A1, the entire stator core is inserted into the resin such that the coil strand is exposed to the outside of the resin to connect a power terminal to the exposed portion of the coil strand.As disclosed in JP 2016-82 643 A1, a structure in which the stator core is formed from resin by insert molding is important from the viewpoint of improving the water resistance.However, in the structure disclosed in JP 2016-82 643 A1, the manufacturing process is complicated because the coil strands led out from the tooth portions are inserted through hole portions corresponding to the number of tooth portions. Moreover, in a process of connecting the power terminal to the coil leg after the stator core is molded of resin, improvement is desired because the number of connection points increases.Accordingly, there is a need for a resin-molded stator and a method for manufacturing a stator.SUMMARYA feature of a stator according to an aspect of this disclosure is that the stator includes the features according to claim 1.According to this configuration, since the terminal to which the end portion of the coil harness is connected is in a state of being exposed from the resin, it is possible to directly connect the terminal to the winding of a control card. Moreover, since a plurality of end portions of terminals of the plurality of coil harnesses are wound around a plurality of yoke portions, it is possible to reduce the number of portions connected to a card (circuit board) or to a power terminal, compared to a configuration in which all end portions of the coil harnesses wound around a tooth portion are led out of the resin because the plurality of end portions are connected to the terminal.Consequently, a stator is formed that facilitates electrical connection to the coil string while having the advantageous effects involved in forming the stator from resin.According to another configuration, a through hole may be drilled in the plate at a position overlapping an intermediate position of the coil strand wound around teeth of the plurality of tooth portions adjacent to each other in the circumferential direction.According to this configuration, when the stator core is accommodated in a cavity of a mold filled with resin, in a case where the resin flows in a direction (direction along a center axis of the annular stator core) perpendicular to the plate surface of the plate, the resin flowing through a space between the coil strands wound around the adjacent tooth portions flows through the through hole of the plate. Thus, there is no change in the position of the plate due to the reduction in the pressure acting on the plate.According to another configuration, an engagement holding portion for individually engaging and holding the plurality of terminals may be provided separately from a separation protrusion portion that separates the terminals, respectively.According to this configuration, it is possible to keep the plurality of terminals in an engagement state with the engagement holding portion, and adjacent terminals from the held terminals are provided while being separated by the separation protrusion portion therebetween. Consequently, it is possible to avoid proximity between the terminals and ensure high terminal insulation property.According to another configuration, an insulator may be provided along an outer periphery of the yoke portion, and a part of the plate may be engaged with the insulator.According to this structure, a part of the plate is engaged with the insulator, whereby it is possible to maintain a state in which respective positional relationships are set.A feature of a method of manufacturing a stator according to another aspect of this disclosure is that the method comprises the steps according to claim 5.According to this configuration, it is possible to manufacture a stator in a state where the terminal to which the end portion of the coil harness is connected is exposed from resin, and also to directly connect the terminal to the wire terminal of the control card. Moreover, the plurality of end portions of the terminals of the plurality of coil harnesses wound around the plurality of tooth portions are connected to the terminals. Consequently, for example, it is possible to reduce the number of regions connected to a circuit board or a power terminal, compared to a structure in which all end portions of the coil strands wound around a yoke portion are led out of the resin.Consequently, a stator is formed that facilitates electrical connection to the coil train and has the advantageous effects achieved by the resin molding.BRIEF DESCRIPTION OF THE DRAWINGSThe above and other features and characteristics of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. The following are shown: FIG. 1 is a cross-sectional view of a water pump; FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 ; FIG. 3 is a perspective view of a stator; FIG. 4 is an exploded perspective view of a stator core and an insulator; FIG. 5 is an exploded perspective view of the stator; FIG. 6 is a cross-sectional view showing the stator being in a mold; and FIG. 7 shows a flow chart of a method for producing a stator.DETAILED DESCRIPTIONAn embodiment will be described below with reference to the drawings.Basic StructureAs shown in FIG. 1, a water pump 100 is formed by connecting a motor housing constituting a motor portion M, a pump housing 2 constituting a pump portion P, and a control housing 3 for controlling a rotation of a pump rotor 6 through the motor portion M.The water pump 100 circulates cooling water between an internal combustion engine and a radiator in a vehicle, for example, in a car. As shown in FIGS. 1, 2 to 3, the motor portion M includes an annular stator 10 integrally formed with the motor housing 1, and a motor rotor 20 rotatably supported about a rotation axis center X.The motor portion M is formed as a DC brushless motor, and the stator 10 has a structure common to a three-phase motor.The pump housing 2 is connected to an end portion of the motor housing 1 and formed into a centrifugal type, having a suction cylinder 2a for sucking cooling water and a discharge cylinder 2b for discharging the cooling water. A support shaft 25 is provided coaxially with the rotation axis center X, and extends from a partition wall 1 aformed in the motor housing 1 in a position perpendicular to the rotation axis center X to an inside of the suction cylinder 2 aof the pump housing. The motor rotor 20 is rotatably supported with respect to the support shaft 25.The control housing 3 is constituted by a cover member provided on a side opposite to the pump housing 2 in the motor housing 1. A control board 4 is provided more inside than the control case 3. Moreover, the pump rotor 6 is integrally formed with the motor rotor 20, and the pump rotor 6 forms a plurality of vanes (vaned wheels) 6b on a disk 6a.Motor SectionAs shown in FIGS. 1, 2, 3, 4 to 5, the motor portion M includes the annular stator 10 integrally formed with the motor housing 1 and the motor rotor 20 rotatably supported with respect to the support shaft 25. The motor rotor 20 includes a rotor core 22 having six permanent magnets 22 aat an end portion of a rotor body 21 made of resin. Moreover, the disk 6 aof the pump rotor 6 is formed at the other end portion of the rotor body 21.The stator 10 includes an annular stator core 11 having a rotation axial center X as a center, an annular plate 15 having the rotation axis center X as a center, a plurality (three) of terminals 16, and a resin 17 for molding the stator core 11 and the plate 15 in a state where a part of the plurality of terminals 16 is exposed. The plate 15 is located at a position where it overlaps the annular stator core 11 in the direction along the rotational axial center X.The stator core 11 is formed by arranging a plurality (nine) of split cores 11S formed by laminating a plurality of magnetic steel plates in the circumferential direction. Each of the split cores 11S has an outer peripheral yoke portion 11 a, an inter-tooth portion 11 b, and an inner peripheral flange portion 11 c, and is covered with an insulator 12 made of an insulating resin.As shown in FIG. 4, the insulator 12 is formed of two parts provided in the lamination direction of the magnetic steel plates so as to surround each split core 11S. The insulator 12 made up of the two parts is integrally formed with an inner flange portion 12 alocated on an inner circumferential side of the stator and an outer flange portion 12 blocated on an outer circumferential side, and a coil bobbin 13 is wound around an intermediate portion between the inner flange portion 12 aand the outer flange portion 12 b. An insulating film is formed on the coil string 13. The insulating film is removed by heating above a predetermined temperature, and a material having a property of exposing a conductor of a strand is used.In a state where end surfaces in the circumferential direction of the yoke portions 11 a, the plurality (nine) of split cores 11S are abutted to each other, the end surfaces are held in such a configuration, and thus the annular stator core 11 is formed.Specifically, a total of three coil strands 13 are used, and one coil strand 13 is wound around a plurality of tooth portions 11 bof one phase (more specifically, wound around the insulators 12). Strand ends 13 aare led outward at three locations, in a state in which the strand ends 13 a(end regions of the strand) of two coil strands 13 are bundled together into three coil strands 13. Moreover, a Y circuit (star circuit) or a Δ circuit (delta circuit) is realized by connecting the string end 13 a lead out as described above to the terminal 16.As shown in FIGS. 3 and 5, the three terminals 16 each have different shapes, and a base portion 16 a, a coil connection portion 16 b, and a circuit board connection portion 16 care formed by pressing a plate material of a good conductor such as a copper alloy. Moreover, a retaining hole portion 16d is drilled in the base portion 16a.The base portion 16a is formed flat. The coil connection portion 16 bis formed to protrude upward from the base portion 16 ain the perpendicular direction, and has an insertion space through which the strand end 13 acan be inserted. The circuit board connection portion 16 cis formed in a forked shape.As shown in FIGS. 3 and 5, the plate 15 is formed of a resin material so as to be annular so as to overlap the annular portion of the stator core in the direction along the rotational axial center X. Engagement holding portions 15 athat individually support the plurality (three) of terminals 16, a plurality of through holes 15 d, and a position aligning portion 15 fformed by cutting away a part of the outer periphery are bored in the plate 15.The engagement holding portions 15 ais recessed having a depth (depth equal to the thickness of the base portion 16 a) into which the base portions 16 aof the three terminals 16 fit, and a separation protrusion portion 15 bis formed at an intermediate position of the engagement holding portions 15 ain a neighboring positional relationship. A retaining shaft 15g inserted into each of the retaining hole portions 16d of the three terminals 16 is formed in each of the engagement retaining portions 15a. A part of the plurality of through holes 15 dis located at a position where an intermediate position space of the coil strand 13 wound around the adjacent tooth portions 11 bin the direction of the rotational axial center X is overlapped.When the stator 10 is assembled, the holding shaft 15 gis inserted into the holding hole portion 16 dof the terminal 16, and a portion of the holding shaft 15 gopposed from the base portion 16 ais used for heat curing (heat curing) connection by heating and pressing to form a large diameter.Moreover, an engaging portion 15 eis formed to protrude on a surface of the plate 15 facing the stator core 11. An engaging cut portion 12 ethat is engageable with the engaging portion 15 eis formed on an inner peripheral portion of the outer flange portion 12 bin the insulator 12.Stator Manufacturing MethodAs shown in FIG. 7, the stator 10 of the water pump 100 is manufactured by sequentially performing a stator core forming step S 1, a joining step S 2, and a forming step S 3.In the stator core forming step S 1, the insulator 12 is set in each of the nine split cores 11S, and the coil string 13 is wound around the insulator 12, and as shown in FIG. 5, the nine split cores 11S are annularly arranged with the end surfaces of the yoke portions 11 aadjacent to each other in the circumferential direction, and the end surfaces are clamped. Moreover, instead of a split core 11S, an annular stator core 11 may be used, which is not divided around which the coil string 13 is wound.In the stator core forming step S 1, the annular stator core 11 in which the coil bobbin 13 is wound around the tooth portion 11 bis formed. Moreover, when the coil line 13 is wound, a coil line 13 is wound around three tooth portions 11 bcorresponding to one phase of a three-phase coil. Consequently, three coil strands 13 are used.When the coil strand 13 is wound, one strand end 13 a(end portions of a winding start) and the other strand end 13 a(end portions of a winding end) on one side (upper side in FIGS. 3 and 5 ) of the stator core 11 are led out. Moreover, two phase ends 13 aof the three coil phases 13 are bundled according to a star connection or delta connection.Next, in the connection step S 2, the plate 15 is provided at an end portion of the stator core 11 on a side where the strand end 13 ais led out, and as shown in FIG. 3, the end portion of the coil strand 13 is connected to the coil connection portion 16 bof the terminal 16 in an inserted state.In the joining step S 2, a posture of the plate 15 is set appropriately with the rotation axis center X as a center, the engagement portion 15 eengages with the engagement portion 12 eof the outer flange portion 12 b, whereby the position of the plate 15 in the direction along the rotation axis center X is set accordingly, based on the position of the position aligning portion 15 f.When the plate 15 is placed, the terminal 16 in each of the three engagement holding portions 15 ais held in advance by heat curing as described above, and two strand ends 13 aof the coil strand 13 are bundled and inserted into the coil connecting portion 16 b. Moreover, the support of the terminals 16 on the three engagement holding portions 15 acan be performed after the board 15 is mounted.The insulating film of the two strand ends 13 ais removed by heat by applying pressure using a joining tool while heating the coil connection portion 16 b, and the two strand ends 13 aare inserted through the inner surfaces of the coil connection portion 16 bin a pressing state.In the connection step S 2, since the two leg ends 13 aand the coil connection portion 16 bare connected on the upper surface of the plate 15, for example, in a situation where the coil leg 13, which is another end portion, is present in the vicinity of the joint, a problem that the connection tool unintentionally comes into contact with the coil leg 13 and thus the insulating film melts can be prevented.In the molding step S 3, as shown in FIG. 6, the stator core 11, the plate 15, and a part of the terminals 16 are accommodated in a space of a mold 13, and a process of injecting resin into the mold is performed.In the molding step S 3, resin in a molten state is injected into a region where the stator core 11 is located in the direction of an arrow In from a side opposite to the end region where the plate 15 is located. The resin flows as shown by the arrow in FIG. 6, and the cavity is filled with the resin by injecting the resin. When the resin flows, it flows through a gap of the intermediate position of the coil strand 13 wound around the adjacent insulators 12 (tooth portions 11 b), and reaches the position of the plate 15.The stator core 11, the plate 15, and a part of the terminals 16 constitute the stator 10 formed by the resin 17 by performing the molding step S 3. Specifically, in the molding step S 3, a process of inserting the support shaft 25 into the partition wall 1 ais also simultaneously performed, thereby forming the motor housing 1.Mounting of Water PumpThe stator 10 manufactured by the manufacturing method is integrally formed with the motor housing 1. Consequently, the motor rotor 20 is located on the inside of the stator 10 (the pump rotor 6 is also arranged at the same time), the pump housing 2 is attached, the circuit board connection portion 16 cof the terminal 16 formed exposed from the resin 17 is connected to a printed winding of the control card 4 by soldering or the like, and the control housing 3 is attached to complete the water pump 100.As described above, the stator 10 molded by the resin 17 is formed such that it is possible not only to directly connect the printed winding of the control card 4 to the terminal 16, but also to shorten the connection process because there are only three terminals 16.In the connection step S 2, moreover, it is possible to prevent disadvantages caused by heat damaging the insulating film of the coil strand 13 during connection. When the resin flows through the inside of the mold 30 during the molding of the resin 17, it is possible to prevent the position of the plate 15 from shifting due to the resin pressure by using the plate (15).The disclosure may be applied to the resin-molded stator and the method for manufacturing a stator.Principles, a preferred embodiment and an application of the present invention have been described above. However, the invention is not limited thereto, and in particular is not limited to the specific embodiments disclosed. The embodiments disclosed herein are merely exemplary and not limiting. Changes and modifications may be made without departing from the scope of the invention. Accordingly, it is expressly understood that changes and modifications and equivalent constructions fall within the scope of the invention as defined in the claims.It is expressly emphasized that all features disclosed in the description and / or the claims are to be regarded as separate and independent from each other for the purpose of original disclosure as well as for the purpose of restricting the claimed invention independently of the combinations of features in the embodiments and / or the claims. It is expressly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of original disclosure as well as for the purpose of restricting the claimed invention, in particular also as a boundary of a range specification.

Claims

A stator (10) comprising: a stator core (11) in which a coil leg (13) is wound around each of a plurality of tooth portions (11b) formed as an annular yoke portion (11a); an annular plate (15) located at a position overlapping an annular portion of the stator core (11) in a direction along an axial center X of the stator core (11); a plurality of terminals (16) supported by the plate (15) and to which end portions (13a) of a plurality of coil legs (13) led out from the stator core (11) are respectively connected; and a resin (17) that encloses the stator core (11) and the plate (15) in a state where a part of the plurality of terminals (16) is exposed, in which a plurality of engagement holding portions (15a) corresponding to the plurality of terminals (16) are recessed in the plate (15) on a side opposite to the stator core (11), and each of the terminals (16) has a flat base portion (16a) that fits in one of the engagement holding portions (15a), a coil connection portion (16b) that protrudes upward in the vertical direction from the base portion (16a) and is connected to the end portion (13a) of a coil harness (13), and a circuit board connection portion (16c) that protrudes to the side of the plate (15) opposite to the stator core (11) and is exposed from the resin (17).The stator according to claim 1, wherein a through hole (15d) is drilled in the plate at a position overlapping an intermediate portion of the coil strand wound around portions of the plurality of tooth portions adjacent to each other in the circumferential direction.The stator according to claim 1 or 2, wherein an engagement holding portion (15a) for individually engaging and holding the plurality of terminals is provided separately from a separation protrusion portion (15b) separating the terminals, respectively.The stator according to any one of claims 1 to 3, wherein an insulator (12) is located along an outer periphery of the yoke portion, and a part of the plate is engaged with the insulator.The method for manufacturing a stator (10) according to any one of claims 1 to 4, comprising: a stator core forming step (S1) of forming a stator core (11) by winding a coil bobbin (13) around each of a plurality of tooth portions (11b) formed in an annular yoke portion (11a); a connecting step (S2) of connecting a plurality of end portions (13a) of the coil bobbin (13), which are led out from the stator core (11), to each of a plurality of terminals (16) located in an annular plate (15) that is at a position to overlap an annular portion of the stator core (11) toward along an axial center of the stator core (11); and a molding step (S3) of enclosing the stator core (11) and the plate (15) with a resin (17) in a state where a part of the plurality of terminals (16) is exposed, in which in the plate (15) on a side opposite to the stator core (11), a plurality of engagement holding portions (15a) corresponding to the plurality of terminals (16) are formed recessed, and each of the terminals (16) includes a flat base portion (16a) fitting in one of the engagement holding portions (15a), a coil connecting portion (16b) protruding upward in the vertical direction from the base portion (16a) and connected to the end portion (13a) of a coil harness (13), and a circuit board connecting portion (16c), which protrudes to the side of the plate (15) facing away from the stator core (11) and is exposed from the resin (17).

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