Slim axial gap-type electric motor and water pump using same

Abstract

The present invention relates to a slim axial gap-type electric motor in which, after an integrated stator is formed, in order to reduce the overall size of the motor, coils are connected to each other in a state where an inner and an outer printed circuit board for coil connection are separately arranged thereinside and thereoutside, and a water pump using same. An axial gap-type electric motor of the present invention comprise a rotor and a stator, wherein the stator comprises: multiple split cores; multiple bobbins formed on the outer circumferences of the multiple split cores, respectively; U, V, and W three-phase coils wound on the outer circumferences of the multiple bobbins; a back yoke having a through-hole coupled to rear ends of teeth of the multiple split cores; an inner printed circuit board on which the U, V, and W three-phase coils are connected in a parallel circuit; and an outer printed circuit board for forming a neutral point for Y-connection of the U, V, and W three-phase coils, wherein each of the multiple bobbins, around which the U, V, and W three-phase coils are wound, has both ends fixed to the inner printed circuit board and the outer printed circuit board.

Description

Slim axial gap type electric motor and water pump using the same

[0001] The present invention relates to a slim axial gap type electric motor and a water pump using the same, and more particularly, to a slim axial gap type electric motor and a water pump using the same, which can increase the efficiency of the motor by forming an integral stator and combining a back yoke and inner and outer printed circuit boards for coil wiring to the teeth of a split core protruding from the rear of the integral stator, and which can significantly reduce the overall height of the pump while achieving complete waterproofing.

[0002] In general, a water pump applied to a vehicle is a device that functions to circulate coolant, and is configured to circulate coolant by rotating a pump impeller by being forcibly driven by a belt to suck in and discharge coolant, and an engine-driven water pump in which a seal unit is assembled inside to prevent coolant from leaking, and an electric water pump that drives an electric motor by electricity provided by a battery or the like, and circulates coolant by rotating an impeller by the electric motor to suck in and discharge coolant are representatively used.

[0003] Among these, the electric water pump has the advantage of increasing engine efficiency and thus improving fuel efficiency compared to the engine-driven water pump because it does not require engine driving power of the vehicle compared to the engine-driven water pump, and furthermore, it provides the advantage of being able to precisely control the temperature of the coolant, and thus has been widely applied to various vehicle models recently.

[0004] In addition, in the case of electric vehicles, hybrid vehicles, or fuel cell vehicles, the importance of electric water pumps is increasing compared to engine-driven water pumps because driving is performed with the engine stopped (in the case of hybrid vehicles) or even in situations where an engine to drive a water pump is not provided (in the case of electric vehicles or fuel cell vehicles).

[0005] Meanwhile, among the above electric water pumps, the canned type electric water pump is a pump driven by an electric motor having a can-shaped sealed container inside a stator, and is structured such that a can structure is inserted between a rotor and a stator, and the hydraulic section is extended to the rotor section so that the rotor is immersed in cooling water, thereby allowing the injected water to appropriately cool the frictional heat generated in the rotor.

[0006] Korean Patent Publication No. 10-2021-0108844 (Patent Document 1) proposes an axial gap type electric motor for a water pump (EWP), including: a rotor rotatably supported in a fluid flow passage between a pump cover and a body case; a stator disposed in a lower space formed by the body case and an upper cover to generate a rotating magnetic field to rotate the rotor; and a partition disposed on an upper portion of the body case to separate the rotor and the stator; wherein the rotor includes a non-rare earth magnet.

[0007] The conventional electric motor structure of Patent Document 1 has a problem of low assembly productivity, as the stator core of the stator is formed in a "T" shape and is composed of a back yoke formed by laminating a plurality of teeth made of soft magnetic composites (SMC) and a plurality of electrical steel plates interconnecting the plurality of teeth.

[0008] In addition, conventional axial gap type motors for water pumps employ a stator in which coils are wound on a bobbin that forms a coil winding area on the outer periphery of the core while using a long stator core in a "T" shape, and since multiple stator cores are arranged parallel to the axial direction, it has been very difficult for the water pump to have a slim structure in the axial direction.

[0009] The present invention has been devised in consideration of such conventional problems, and its purpose is to form an integral stator by insert molding using a bulk molding compound (BMC) or an insulating heat-dissipating composite made of plastic after winding a coil on a bobbin formed integrally around the outer periphery of a plurality of split cores formed of soft magnetic powder (SMC: Soft Magnetic Composites) or a plurality of silicon steels laminated and formed, and then using a heat-dissipating BMC (Bulk Molding Compound) or a plastic, which has a heat-dissipating effect, and a back yoke that functions as a magnetic circuit and inner and outer printed circuit boards (PCBs) for coil wiring are combined to the teeth of the split cores protruding toward the rear, and the shoe portion of the split core is exposed to the fluid flow passage to minimize the air gap and minimize the generation of magnetic flux leakage, thereby promoting an increase in motor efficiency, and to provide a slim axial gap type electric motor and a water pump using the same, which can significantly reduce the overall height of the pump while implementing complete waterproofing.

[0010] Another object of the present invention is to provide a slim axial gap type electric motor and a water pump using the same, which can significantly reduce the overall height of the pump by using an inner and / or outer printed circuit board (PCB) for coil wiring separately on the side of the bobbin or the outer or inner side of the back yoke.

[0011] Another object of the present invention is to provide a slim axial gap type electric motor and a water pump using the same, which can significantly reduce the overall height of the pump while increasing the efficiency of the motor by forming an integral stator and then assembling it at the bottom in a body case having a thin plate partition between the rotor and the stator.

[0012] Another object of the present invention is to provide a slim axial gap type electric motor and a water pump using the same, in which, after forming an integral stator, inner and / or outer printed circuit boards (PCBs) for coil wiring are arranged separately on the inner and outer sides to reduce the overall size, and coil wiring is performed, and a power terminal pin is used to connect the inner and / or outer printed circuit boards (PCBs) for coil wiring and a driving printed circuit board (PCB) in which a motor drive circuit is implemented.

[0013] Another object of the present invention is to provide a slim axial gap type electric motor capable of implementing complete waterproofing while significantly reducing the overall height of the pump by winding a coil on a bobbin integrally formed on the outer periphery of a plurality of split cores formed of a soft magnetic powder (SMC) or a plurality of silicon steels laminated and then insert-molding and integrating the coil with a body case using an insulating heat-dissipating composite material made of BMC or plastic having a heat-dissipating effect, and a water pump using the same.

[0014] Another object of the present invention is to provide a slim axial gap type electric motor and a water pump using the same, which can facilitate coil winding by forming a coil guide groove on a bobbin to avoid the problem of the covering of a coil start wire being peeled off when winding a coil on a bobbin, or can prevent the covering of a coil start wire from being peeled off and causing damage.

[0015] Another object of the present invention is to provide a slim axial gap type electric motor and a water pump using the same, which can easily implement parallel circuit connection of U, V, and W three-phase coils and a neutral point for Y-connection by using an inner and / or outer printed circuit board (PCB) for coil connection after forming an integral stator.

[0016] Another object of the present invention is to provide a slim axial gap type electric motor having magnetic energy equivalent to that of an electric motor using a rare earth magnet even when a ferrite magnet, which is a non-rare earth magnet, is used, by reducing the air gap between the rotor and the stator, and a water pump using the same.

[0017] Another object of the present invention is to provide a slim axial gap type electric motor with a simple structure and a waterproof design that enables complete waterproofing, and a water pump using the same.

[0018] According to one embodiment of the present invention, an axial gap type electric motor for an electric water pump (EWP) comprises: a rotor rotatably supported in a fluid flow passage between a pump cover and a body case; and a stator integrally formed with the body case to generate a rotating magnetic field to rotate the rotor, wherein the stator comprises: a plurality of split cores each having a “T” shape in cross section; a plurality of bobbins formed on the outer periphery of each of the plurality of split cores; a U, V, W three-phase coil wound on the outer periphery of the plurality of bobbins; a back yoke having a plurality of through-holes arranged in an annular shape, the through-holes being coupled to rear ends of teeth of the plurality of split cores; an inner printed circuit board (PCB) on which a parallel circuit connection of the U, V, W three-phase coils is formed; And an outer printed circuit board (PCB) for forming a neutral point for Y-connection of the U, V, W three-phase coil; wherein each of the plurality of bobbins on which the U, V, W three-phase coils are wound is characterized in that both ends are fixed to the inner printed circuit board (PCB) and the outer printed circuit board (PCB).

[0019] In this case, the stator may have a shoe of each of the plurality of split cores exposed to the fluid flow passage.

[0020] In addition, the U, V, W three-phase coils may form a parallel circuit by connecting the start lines of a plurality of coils assigned to each of the U, V, and W phases, and may form a neutral point (COM) for Y-connection by commonly connecting the end lines of the plurality of coils, and the inner printed circuit board (PCB) may include first to third conductive patterns for commonly connecting the start lines of the plurality of coils assigned to each of the U, V, and W phases, and the outer printed circuit board (PCB) may include a circular conductive pattern to which all the end lines of the plurality of coils assigned to each of the U, V, and W phases are commonly connected.

[0021] Furthermore, the axial gap type motor according to the present invention may further include U, V, W power terminal pins, each of which has one end connected to the first to third conductive patterns so as to be connected to the U, V, W three-phase output terminals of the inverter circuit through the connector housing.

[0022] According to another embodiment of the present invention, an axial gap type electric motor for an electric water pump (EWP) comprises: a rotor rotatably supported in a fluid flow passage between a pump cover and a body case; a stator disposed in a lower space formed by the body case and an upper cover for generating a rotating magnetic field to rotate the rotor; and a partition wall disposed on an upper portion of the body case for separating the rotor and the stator; wherein the stator comprises: a plurality of split cores each having a cross-section having a "T" shape; a plurality of bobbins formed on the outer periphery of each of the plurality of split cores; a U, V, W three-phase coil wound on the outer periphery of the plurality of bobbins; a back yoke having a plurality of through-holes arranged in an annular shape, the through-holes being coupled to rear ends of teeth of the plurality of split cores; an inner printed circuit board (PCB) on which a parallel circuit connection of the U, V, W three-phase coils is formed; And an outer printed circuit board (PCB) for forming a Y-connection of the U, V, W three-phase coils; wherein the plurality of bobbins on which the U, V, W three-phase coils are wound are characterized in that both ends are fixed to the inner printed circuit board (PCB) and the outer printed circuit board (PCB).

[0023] In this case, the stator may be press-fitted with the plurality of split cores into through holes formed in the bulkhead so that each shoe may be exposed to the fluid flow passage.

[0024] In addition, the bulkhead of the body case has a plurality of through holes at positions corresponding to the plurality of split cores, and the heads of the plurality of split cores coupled to the plurality of through holes are positioned so that the shoes are exposed to the fluid flow passage, and the split cores may be made of a soft magnetic powder (SMC).

[0025] Furthermore, the bulkhead of the body case has a plurality of through holes at positions corresponding to the plurality of split cores, and the heads of the plurality of split cores coupled to the plurality of through holes are positioned so that the shoes are exposed to the fluid flow passage, and the split cores are formed by laminating silicon steel, and can be waterproof-sealed so that the exposed shoes and the bulkhead form the same plane.

[0026] According to one embodiment of the present invention, a water pump (EWP) includes a pump housing having a pump cover having an inlet for introducing fluid and an outlet for discharging the introduced fluid, and a body case coupled to a lower portion of the pump cover to form a fluid flow passage between the inlet and the outlet; a rotor rotatably supported in the fluid flow passage; an impeller integrally formed with the rotor on an upper side of the rotor; and a stator integrally formed with the body case to generate a rotating magnetic field to rotate the rotor, wherein the stator includes a plurality of split cores each having a “T” shape in cross section; a plurality of bobbins formed on the outer periphery of each of the plurality of split cores; a U, V, W three-phase coil wound on the outer periphery of the plurality of bobbins; a back yoke having a plurality of through holes arranged in an annular shape, the through holes being coupled to rear ends of teeth of the plurality of split cores; an inner printed circuit board (PCB) on which a parallel circuit connection of the U, V, W three-phase coils is formed; And an outer printed circuit board (PCB) for forming a neutral point for Y-connection of the U, V, W three-phase coil; wherein each of the plurality of bobbins on which the U, V, W three-phase coils are wound is characterized in that both ends are fixed to the inner printed circuit board (PCB) and the outer printed circuit board (PCB).

[0027] In this case, the stator has a shoe of each of the plurality of split cores exposed to the fluid flow passage, and the split cores may be made of a soft magnetic powder (SMC).

[0028] In addition, the plurality of split cores may be formed integrally with a partition wall for separating the rotor and the stator, each of which is disposed on the upper portion of the body case so that the shoe portion of the head is exposed to the fluid flow passage.

[0029] Furthermore, the water pump according to the present invention further includes a driver printed circuit board (PCB) mounted on a lower side of the stator and having a motor drive circuit for applying a motor drive signal to the U, V, W three-phase coil of the stator, wherein the inner printed circuit board and the driver printed circuit board are electrically connected using a plurality of connection pins, and the driver printed circuit board and the connector housing can be connected using a plurality of power terminal pins.

[0030] In addition, the U, V, W three-phase coils may form a parallel circuit by connecting the start lines of a plurality of coils assigned to each of the U, V, and W phases, and may form a neutral point (COM) for Y-connection by commonly connecting the end lines of the plurality of coils, and the inner printed circuit board (PCB) may include first to third conductive patterns for commonly connecting the start lines of the plurality of coils assigned to each of the U, V, and W phases, and the outer printed circuit board (PCB) may include a circular conductive pattern to which all the end lines of the plurality of coils assigned to each of the U, V, and W phases are commonly connected.

[0031] Furthermore, the water pump according to the present invention may further include a support shaft receiving portion formed to extend downwardly in the center of a bulkhead formed on the upper portion of the body case; a support shaft having a hollow portion with a lower end fixed to the center of the support shaft receiving portion and a screw tap formed therein; a rotor support body for integrating an impeller with the upper portion of the rotor; a bearing housing formed to protrude downwardly in the center of the rotor support body; and a sleeve bearing installed inside the bearing housing to rotatably support the rotor and the impeller about the support shaft.

[0032] As described above, in the present invention, a coil is wound on a bobbin formed integrally around the outer periphery of a plurality of split cores formed of soft magnetic powder (SMC: Soft Magnetic Composites) or a plurality of silicon steels laminated and formed, and then an insulating heat-dissipating composite material made of bulk molding compound (BMC) having a heat-dissipating effect is used to form an integral stator by insert molding, thereby preventing moisture penetration. In addition, inner and outer printed circuit boards (PCBs) for coil wiring and a back yoke that serves as a magnetic circuit are combined with teeth of the split cores protruding toward the rear, thereby exposing the shoe portion of the split cores to the fluid flow passage, thereby minimizing the air gap and minimizing the generation of magnetic flux leakage, thereby promoting an increase in motor efficiency, and it is possible to realize complete waterproofing while significantly reducing the overall height of the pump.

[0033] In addition, in the present invention, the overall height of the pump can be significantly reduced by using the inner and / or outer printed circuit boards (PCBs) for coil wiring separately on the side of the bobbin or the outer or inner side of the back yoke.

[0034] In this case, only one of the inner and outer printed circuit boards (PCBs) can be used if the inner or outer diameter size is sufficient.

[0035] Furthermore, in the present invention, after forming an integrated stator, in order to reduce the overall size, the coil wiring is performed by dividing the inner and / or outer printed circuit boards (PCBs) for coil wiring into the inner and outer sides and arranging them, and a power terminal pin can be used to connect between the inner and / or outer printed circuit boards (PCBs) for coil wiring and the driving printed circuit board (PCB) in which the motor drive circuit is implemented.

[0036] In addition, in the present invention, a coil is wound on a bobbin formed integrally around the outer periphery of a plurality of split cores formed of soft magnetic powder (SMC: Soft Magnetic Composites) or a plurality of silicon steels laminated and formed, and then an insulating heat-dissipating composite material made of bulk molding compound (BMC) or plastic having a heat-dissipating effect is used to insert-mold and integrate the coil into the body case, thereby significantly reducing the overall height of the pump while achieving complete waterproofing.

[0037] Moreover, conventionally, when winding a coil on a bobbin, a coil start wire comes out from the outside and is wound from the inside of the bobbin and then layer by layer toward the outside. However, if there is no start wire escape groove, the start coil may collide with the coil during coil winding, causing the coating of the coil to peel off, which may cause problems with aligned winding. In the present invention, in order to avoid the problem of the coating of the coil start wire being peeled off when winding a coil on a bobbin, a coil guide groove is formed on the bobbin to facilitate coil winding or prevent the coating of the coil start wire from being peeled off and causing damage.

[0038] In the present invention, only one coil guide groove can be formed so that the coil start line's winding start point can be located only on either the left or right, or two coil guide grooves can be formed so that the coil start line's winding start point can be located on both the left and right sides. In the illustrated embodiment, the coil guide groove exists only on the outside, but it is also possible to set it on the inside.

[0039] In the present invention, after forming an integrated stator, a parallel circuit connection of U, V, and W three-phase coils and a neutral point for Y-connection can be easily implemented by using an inner and / or outer printed circuit board (PCB) for coil connection.

[0040] In the present invention, the air gap can be reduced by separating the rotor and stator without using a thin plate barrier, so that even when using a non-rare-earth magnet, a ferrite magnet, the motor has magnetic energy equivalent to that of a motor using a rare-earth magnet containing Nd. Furthermore, the performance of the motor can be improved by using a rare-earth magnet containing bonded Nd.

[0041] Furthermore, the electric motor of the present invention is an axial gap type with a rotor and stator facing each other, and thus can be used in an open structure without the need for a separate magnetic waterproof structure such as a rare earth magnet. Therefore, compared to conventional electric motors employing rare earth magnets, the air gap can be further reduced, thereby increasing the efficiency of the electric motor.

[0042] In the present invention, a slim structure can be realized by placing the main printed circuit board (PCB) for the motor drive circuit outside the pump housing, and it is also possible to place the main printed circuit board (PCB) for the motor drive circuit inside the pump housing.

[0043] FIG. 1 is a perspective view of a water pump using an axial gap type electric motor according to an embodiment of the present invention.

[0044] Fig. 2 is a front view of a water pump using an axial gap type electric motor according to an embodiment of the present invention.

[0045] FIG. 3 is a plan view of a water pump using an axial gap type electric motor according to a first embodiment of the present invention.

[0046] Figures 4a and 4b are cross-sectional views taken along line AA and line BB of Figure 3, respectively.

[0047] Figure 5 is an exploded perspective view of a water pump using an axial gap type electric motor according to an embodiment of the present invention.

[0048] Figures 6a and 6b are a perspective view and an exploded perspective view, respectively, of the water pump of Figure 1 with the upper cover removed.

[0049] FIGS. 7A to 7C are a plan view, a bottom perspective view, and an exploded perspective view, respectively, of a stator of an axial gap type motor according to an embodiment of the present invention.

[0050] Figures 8a and 8b are perspective views of the assembled state of the split core, bobbin, and back yoke, respectively, and a cross-sectional view taken along line DD of Figure 8a.

[0051] Figures 9a and 9b are perspective views showing an insulating bobbin coupled to a tooth of a split core and a perspective view of the split core, respectively.

[0052] Figures 10a and 10b are a plan view of the assembled state of the inner PCB and the outer PCB and a circuit diagram for parallel circuit wiring of the U, V, and W three-phase coils, respectively.

[0053] Figures 11 and 12 are cross-sectional views of a water pump using an axial gap type electric motor according to the second and third embodiments of the present invention, respectively.

[0054] Hereinafter, a preferred embodiment according to the present invention will be described with reference to the attached drawings.

[0055] In this process, the sizes and shapes of components depicted in the drawings may be exaggerated for clarity and convenience. Furthermore, terms specifically defined in consideration of the structure and operation of the present invention may vary depending on the intent or custom of the user or operator. Definitions of these terms should be based on the content throughout this specification.

[0056] The axial gap type motor employing the non-rare earth magnet of the present invention can be implemented as a vertical shaft motor and is applied to a built-in water pump (EWP), compressor, oil pump, etc. In the following description, an example of the axial gap type motor being applied to a water pump (EWP) is described.

[0057] Referring to FIGS. 1 to 6b, a water pump (EWP) (100) using an axial gap type electric motor according to a first embodiment of the present invention largely includes a pump housing (10), an axial gap type electric motor (200), and an impeller (20).

[0058] The above pump housing (10) has an inlet (11a) for introducing a fluid such as a coolant at the center of one end, an outlet (11b) for discharging the introduced fluid is formed extending at one end of the other end, and includes a pump cover (11) that is open at the center of the other end, and a body case (12) that is formed in an inverted cup shape so as to cover the open portion of the pump cover (11) to form a fluid flow passage (P) inside the pump cover (11), and to have a lower space outside the fluid flow passage (P).

[0059] In this case, the pump housing (10) may include an upper cover that is separated from the body case (12) and coupled to the lower part of the body case (12) so that the stator (40) of the electric motor (200) can be easily assembled into the sealed lower space inside the body case (12).

[0060] In the present invention, the driver for driving the stator (40) may be placed outside the pump housing (10) to form a slim water pump (EWP) (100). However, the driver may also be formed integrally with a printed circuit board (PCB) (50) for the driver placed inside the pump housing (10), as illustrated in FIG. 12.

[0061] The pump cover (11) above has an O-ring (17) attached to the outer circumference of the inlet (11a) to be used for sealing when combined with the fluid supply unit that supplies fluid.

[0062] The above pump cover (11) and body case (12) are preferably formed in a cylindrical shape and have a mutually fixed connection structure. For mutually fixed connection between the pump cover (11) and the body case (12), for example, five fixing screws or fixing bolts are fastened to the connection holes formed in the outer periphery of the pump cover (11) and the body case (12).

[0063] The above pump cover (11) and body case (12) are preferably formed in a cylindrical shape and have a mutually fixed connection structure. For mutually fixed connection between the pump cover (11) and the body case (12), a fixing screw or fixing bolt (11e) is fastened to a connection hole provided in a plurality of protrusions (11c, 12a) protruding from the outer periphery of the pump cover (11) and the body case (12).

[0064] Additionally, an O-ring (18) for sealing can be inserted into the outer peripheral portion where the pump cover (11) and the body case (12) are mutually joined.

[0065] Moreover, an O-ring is inserted into the joint between the body case (12) and the upper cover to maintain the sealing state of the lower space.

[0066] In addition, it is possible to achieve a more perfect sealing state by joining the joint between the body case (12) and the upper cover using a laser welding method.

[0067] A connector housing (13a) is integrally extended from the lower portion of one side of the body case (12) or the upper cover to apply a driving signal from a driver disposed externally to a stator (40) disposed inside the housing (10). As described later, U, V, W power terminal pins (55c) are built into the inside of the connector housing (13a) to be connected to an inner printed circuit board (PCB) (44a) for coil wiring.

[0068] The pump cover (11), body case (12) and upper cover forming the above pump housing (10) can be formed using a resin such as, for example, PPS (Poly Phenylene Sulfide).

[0069] An impeller (20) having a rotor (30) of an electric motor (200) integrally formed on the lower side is disposed in the fluid flow passage (P) of the folded portion between the inlet (11a) and the outlet (11b) of the pump cover (11).

[0070] In addition, the open bottom of the pump cover (11) is extended to secure a wider space than the inlet (11a) so that the impeller (20) can be placed in the fluid flow passage (P), and a groove structure is formed on the upper part of the body case (12) corresponding to the open bottom of the pump cover (11).

[0071] The above impeller (20) has a plurality of blades (23) radially arranged between a circular upper plate (21) and a lower plate (22) so as to discharge a fluid such as cooling water flowing in from an inlet (11a) through an outlet (11b) arranged on the side. The upper plate (21) has a narrow-bottomed shape with a through hole formed in the center and an increasing diameter from top to bottom, and the lower plate (22) is formed as a circular plate that surrounds the upper side and the outer periphery of the rotor (20).

[0072] The above pump cover (11) has a flange formed to extend from the lower portion of the body that accommodates the impeller (20) inside so as to have the same outer diameter as the outer diameter of the body case (12). A plurality of reinforcing ribs (11f) are formed radially on the outer circumference of the body to reinforce the strength of the body.

[0073] Accordingly, the lower plate (22) is formed with the same diameter as the upper plate (21) corresponding to the diameter of the flange. In this case, the lower plate (22) and the rotor support (33) of the rotor (30) can be integrated using an insert molding method.

[0074] In addition, a bearing housing (62) is formed to protrude downward in the center of the rotor support (33), and a sleeve bearing (61) that rotatably supports the rotor support (33) of the rotor (30) is installed in the bearing housing (62).

[0075] A support shaft receiving portion (12c) is formed extending downwardly in the central portion of a bulkhead (12d) formed on the upper portion of the body case (12), and a lower portion of a support shaft (60) having a cross-section in the shape of the letter "U" is insert-molded and fixed to the center of the support shaft receiving portion (12c). In this case, a hollow portion (60a) having a screw tap formed therein is formed inside the support shaft (60), and by fastening a fixing bolt (24) to the hollow portion (60a), the impeller (20) and the rotor support (33) of the rotor (30) can be rotatably supported on the support shaft (60).

[0076] A thrust bearing (63) is inserted into the upper side of the support shaft receiving portion (12c) to support the lower side of the sleeve bearing (61).

[0077] Considering that the above sleeve bearing (61) comes into contact with a fluid, it is preferable to use an oilless bearing such as a carbon bearing or a plastic bearing.

[0078] Meanwhile, the present invention employs an axial gap type electric motor (200) including a stator (40) arranged in a sealed lower space inside the body case (12) and a rotor (30) arranged opposite the stator (40) in a fluid flow passage (P) outside the body case (12) as a driving means for rotating the impeller (20).

[0079] First, the rotor (30) is formed as a single body with the impeller (20) by sequentially installing a ring-shaped back yoke (31) and a magnet (32) on the lower surface of the lower plate (22). The magnet (32) of the rotor (30) may be formed of a plurality of N-pole and S-pole split magnet pieces, or a magnet in which the N-pole and S-pole are multi-polarly split and magnetized in a ring-shaped magnet may be used. The back yoke (31) is installed on the back surface of the magnet (32) to form a magnetic circuit.

[0080] The above back yoke (31) may be formed of, for example, a laminate of electrogalvanized steel sheets (EGI steel sheets).

[0081] A thin plate partition (12d) is installed on the upper part of the above body case (12) to separate the stator (40) and the rotor (30), and a plurality of split cores (41) are integrally formed in the partition (12d) by insert molding. In this case, the shoe (41a) portion of each of the plurality of split cores (41) is positioned so as to be exposed to the fluid flow passage (P).

[0082] As a result, a completely waterproof structure is implemented for the stator (40) of the present invention. That is, the stator (40) partially or completely formed integrally with the body case (12) can completely block contact with water in the fluid flow passage (P).

[0083] The above-mentioned bulkhead (12d) is formed with a relatively thin thickness compared to the cylindrical portion of the body case (12), and the stator (40) formed partially or entirely integrally with the body case (12) is positioned so that the shoe (41a) portion of each of the plurality of split cores (41) is exposed to the fluid flow passage (P), so that the magnet of the rotor (30) can use a ferrite magnet, which is a non-rare earth magnet, as described below.

[0084] That is, the electric motor (200) of the present invention is an axial gap type in which the rotor (30) and the stator (40) face each other with a thin plate partition (12d) therebetween, and can be used in an open structure without the need for a separate magnet waterproof structure such as a rare earth magnet. That is, even if the electric motor (200) according to the present invention is operated for a long time in a state in which the magnet (32) of the rotor (30) is in contact with the cooling water flowing in the fluid flow passage (P) inside the pump cover (11), the performance of the magnet does not deteriorate. Therefore, the electric motor (200) of the present invention can further reduce the air gap and increase efficiency compared to an electric motor that employs a rare earth magnet having a magnet waterproof structure.

[0085] In addition, in the present invention, when applying a longitudinal-axis type motor having the same outer diameter as a general internal-rotor type motor, it is possible to reduce the air gap by separating the magnet of the rotor (30) and the core of the stator (40) using a thin plate partition (12d), so that even if a ferrite magnet, which is a non-rare-earth magnet, is used, an axial gap type motor having the same magnetic energy as a motor using a rare-earth magnet containing Nd can be implemented.

[0086] However, in the present invention, it is also possible to improve the torque of the motor by using a bonded Nd magnet as the magnet of the rotor (30).

[0087] The above support shaft (60) can be integrally formed by insert molding in which a part of the support shaft (60) is inserted into the central portion of the partition wall (12d) during injection molding of the body case (12), or can be fixed by pressing into the support shaft receiving portion (12c) formed integrally in the central portion of the partition wall (12d).

[0088] A portion of the above-mentioned support shaft receiving portion (12c) extends from the bulkhead (12d) to the lower space and has a sufficient contact area to firmly support the lower end of the support shaft (60).

[0089] Hereinafter, a slim stator of an axial gap type motor according to one embodiment of the present invention will be described with reference to FIGS. 7a to 10b.

[0090] First, the body case (12) is injection-molded to form a plurality of through holes (12e) corresponding to the teeth (41c) of the plurality of split cores (41) in the bulkhead (12d) portion facing the rotor.

[0091] The stator (40) of the present invention is assembled by forming a bobbin (43) integrally or separately on the outer periphery of each tooth (41c) of a plurality of split cores (41).

[0092] As shown in Fig. 9a, the bobbin (43) has upper and lower flanges (43a, 43b) extended to form coil winding regions (43c) on the upper and lower portions, respectively.

[0093] A coil guide (43d) is formed extending from the lower flange (43b) of the bobbin (43) to form a coil guide groove in the bobbin (43) to avoid the problem of the covering of the coil start wire being peeled off when winding the coil (45) in the coil winding area (43c) of the bobbin (43).

[0094] In the present invention, only one coil guide groove can be manufactured so that the coil start line's winding start point can be located only on either the left or right side, or two coil guide grooves can be formed so that the coil start line's winding start point can be located on both the left and right sides. In the illustrated embodiment, the coil guide groove exists only on the lower side (outer side), but it is also possible to set it on the upper side (inner side).

[0095] In the past, when winding a coil on a bobbin, a coil start wire would come out from the outside and be wound from the inside of the bobbin and then layer by layer to the outside. However, if there is no start wire escape groove, the start coil may collide with the coil during coil winding, causing the coil coating to peel off and problems with the aligned winding may occur.

[0096] In the present invention, by providing a coil guide (43d) that forms a coil guide groove inside, coil winding can be facilitated or the covering of the coil start wire can be prevented from being peeled off and causing damage.

[0097] After that, a coil (45) is wound on the coil winding area (43c) of the bobbin (43) and a back yoke (42) is assembled on the rear end of the tooth (41c) of the split core (41).

[0098] The above back yoke (42) has a plurality of through holes (42a) formed corresponding to the teeth (41c) of the plurality of split cores (41), and a through hole (42b) having an inner circumference similar to an inner printed circuit board (PCB) (44a) for coil wiring, which will be described later, is formed in the central portion.

[0099] A bobbin (43) is coupled to each of the above-described plurality of split cores (41), and six bobbins (43) on which U, V, and W three-phase coils (U1-U2, V1-V2, W1-W2) are wound are assembled between an inner printed circuit board (PCB) (44a) and an outer printed circuit board (PCB) (44b) as shown in Fig. 10a to form a stator assembly (i.e., a stator).

[0100] In this case, the bobbin (43) has inner and outer projections (43e, 43f) extended on the inner and outer sides, respectively, for fixing the bobbin, and a through hole for fastening a fixing screw or fixing bolt is formed in each of the inner and outer projections (43e, 43f).

[0101] The inner protrusion (43e) for fixing the bobbin is fixed to the inner printed circuit board (PCB) (44a), and the outer protrusion (43f) for fixing the bobbin is fixed to the outer printed circuit board (PCB) (44b).

[0102] The above stator assembly is formed by press-fitting the shoe (41a) portion located at the tip of a plurality of split cores (41) into the through hole (12e) of the body case (12), and then coating the boundary portion between the shoe (41a) exposed to the fluid flow passage (P) and the through hole (12e) of the body case (12) with, for example, epoxy, to achieve waterproofing and bonding.

[0103] Accordingly, the stator (40) of the present invention is installed in a lower space where the stator (40) maintains a sealing state by being press-fitted and fixed so that a plurality of split cores (41) are positioned so that the shoe (41a) portion is exposed to the fluid flow passage (P) in the body case (12), and can be arranged axially opposite to the rotor (30) to form an axial gap type motor.

[0104] As described later with reference to FIG. 10a, the above stator (40) can easily implement a parallel circuit connection of U, V, and W three-phase coils and a neutral point for Y-connection using an inner printed circuit board (PCB) (44a) and an outer printed circuit board (PCB) (44b).

[0105] In the present invention, a printed circuit board (PCB) (50) for a driver for driving the stator (40) may be installed in the lower space as shown in FIG. 12, or may be placed outside the pump housing (10) to form a slim water pump (EWP) (100) as shown in FIG. 11.

[0106] As shown in Fig. 12, a plurality of connection pins can be used to electrically connect between the inner printed circuit board (PCB) (44a) and the driver printed circuit board (PCB) (50), and a power terminal pin (55c) can be used to connect between the driver printed circuit board (PCB) (50) and the connector (13).

[0107] The above-described plurality of split cores (41) each have a shoe (41a) having a flat end exposed to a fluid flow passage (P), a fan-shaped head (41b), and teeth (41c) that extend from the head (41b) and protrude in a triangular or rectangular shape corresponding to the through hole (42a) of the back yoke (42).

[0108] The above multiple split cores (41) may each be formed of soft magnetic powder (SMC: Soft Magnetic Composites) or may be formed by laminating multiple silicon steels.

[0109] The above-described plurality of split cores (41) may each be made of isotropic magnetic materials having high magnetic permeability, low coercivity and high saturation magnetic induction, such as Fe-Ni, Fe-Co, and Fe-Si alloy powders, as soft magnetic powders (SMC). If the split cores (41) are manufactured using compression molding or extrusion molding using such soft magnetic powders (SMC), they can be formed into a 3D structure, and the cores have isotropic properties.

[0110] In the present invention, the split core (41) can be easily manufactured using a soft magnetic powder (SMC), and a “rounding (R)” required for forming a curve can be easily formed in the shoe portion to obtain a back EMF (Back Electromotive Force) waveform of a sine curve to prevent the occurrence of noise and vibration when the rotor of the driving motor rotates.

[0111] The split core (41) of the present invention can be formed by mixing amorphous metal powder with a binder and forming it in addition to compression molding of a soft magnetic powder (SMC), or by mixing amorphous metal powder, spherical soft magnetic powder (SMC), and a binder in a predetermined ratio. In this case, compared to using 100% of the amorphous metal powder, mixing spherical soft magnetic powder (SMC) in a predetermined ratio can resolve the difficulty of high-pressure sintering and increase the permeability.

[0112] In this case, when the plurality of split cores (41) are each made of soft magnetic powder (SMC: Soft Magnetic Composites), the split cores compression-molded with the soft magnetic powder (SMC) do not form rust when in contact with water.

[0113] When injection molding the above body case (12), a split core (41) made of soft magnetic powder (SMC) or silicon steel can be formed integrally by insert molding so that the shoe (41a) is positioned so that it is exposed to the fluid flow passage (P).

[0114] In addition, when a split core (41) made of a soft magnetic powder (SMC) or silicon steel is assembled and combined into the body case (12), a plurality of through holes (12e) are formed in the partition wall (12d) of the body case (12) at positions corresponding to the plurality of split cores (41), and after the shoes (41a) of the plurality of split cores (41) are positioned so as to be exposed to the fluid flow passage (P), a waterproof sealing treatment can be performed using epoxy or urethane at the boundary between the shoes (41a) and the through holes (12e).

[0115] In this structure where the shoe (41a) of the plurality of split cores (41) is exposed to the fluid flow passage (P), the gap between the rotor (30) and the stator (40) can be set to a minimum interval of 0.1 to 0.2T, thereby improving the efficiency of the motor.

[0116] In this case, if the plurality of split cores (41) are each formed by laminating a plurality of silicon steels, the split cores (41) made of silicon steel may form rust when in contact with water.

[0117] Accordingly, in this case, a plurality of through holes (12e) are formed in positions corresponding to the plurality of split cores (41) in the bulkhead (12d) of the body case (12), and the shoes (41a) of the plurality of split cores (41) are positioned so as to be exposed to the fluid flow passage (P), and then a waterproof sealing treatment can be performed by coating a thin film of epoxy or urethane so that the exposed shoes (41a) and the bulkhead (12d) form the same plane.

[0118] A plurality of teeth (41c) protruding from the lower portion of the above bobbin (43) are connected to the through holes (42a) of the back yoke (42) that form the magnetic circuit.

[0119] By fixing the teeth (41c) of the above-described plurality of split cores (41) to the through-holes (42a) of the back yoke (42) by, for example, press-fitting, a core-type stator (40) is formed. As a result, the leakage magnetic flux that deviates from the path in the magnetic circuit formed between the coil (45) of the stator (40) and the magnet (32) of the rotor (30) can be minimized, thereby increasing motor efficiency.

[0120] In addition, the stator (40) of the present invention can realize a slim structure by press-fitting the head (41b) of the split core (41) into the bulkhead (12d) of the body case (12).

[0121] The water pump (100) according to the present invention is driven by an axial gap type electric motor (200) in a U, V, W three-phase BLDC manner, and the slots and poles can be configured in a ratio of 3:4 or 3:2. The axial gap type electric motor (200) can be configured as a BLDC motor with a structure of, for example, 12 poles - 9 slots or 8 poles - 6 slots.

[0122] When the above motor (200) has an 8-pole-6-slot structure as shown in FIG. 7c, the U, V, W three-phase coils (total of 6 coils) (U1-U2, V1-V2, W1-W2) wound on the 6 split cores (41) of the stator (40) can form a parallel circuit as shown in FIG. 10b with 2 coils (U1-U2, V1-V2, W1-W2) for each of the U, V, and W phases.

[0123] The six split cores (41) in which the U, V, W three-phase coils (U1-U2, V1-V2, W1-W2) are wound on a bobbin (43) are designed so that the U1, V1, W1, U2, V2, W2 coils are sequentially arranged for each of the U, V, and W phases, as shown in Fig. 10a. The inner printed circuit board (PCB) (44a) and the outer printed circuit board (PCB) (44b) are designed so that the U1, V1, W1, U2, V2, W2 coils are sequentially arranged for each of the U, V, and W phases.

[0124] Referring to Fig. 10a, the inner printed circuit board (PCB) (44a) has six connection terminals arranged so that the U, V, and W three-phase coils (U1-U2, V1-V2, W1-W2) are arranged in the order of U1, V1, W1, U2, V2, W2, and two coils (U1-U2, V1-V2, W1-W2) for each of the U, V, and W phases are interconnected by connecting the start lines of each of the U1-U2, V1-V2, and W1-W2 coils to connect a parallel circuit.

[0125] In addition, as shown in Fig. 7b, one side of the U, V, W power terminal pin (55c) is connected to the start line of the U2, V2, W2 coils so as to be connected to the U, V, W three-phase output terminals (Uout, Vout, Wout) of the inverter circuit (56) provided in the motor drive circuit.

[0126] In order to interconnect the start lines of each of the U1-U2, V1-V2 and W1-W2 coils, three patterned first to third conductive patterns (441-443) are formed on the substrate (440) of the inner printed circuit board (PCB) (44a).

[0127] The first conductive pattern (441) connects the start line (U-phase S) of the U-phase coil (U1) arranged on the upper side (0 degrees) of the inner printed circuit board (PCB) (44a) and the start line (U-phase S) of the U-phase coil (U2) arranged on the lower side (180 degrees), the second conductive pattern (442) connects the start line (V-phase S) of the V-phase coil (V1) arranged on the 60 degrees of the inner printed circuit board (PCB) (44a) and the start line (V-phase S) of the V-phase coil (V2) arranged on the 240 degrees, and the third conductive pattern (443) connects the start line (W-phase S) of the W-phase coil (W1) arranged on the 120 degrees of the inner printed circuit board (PCB) (44a) and the start line (W-phase S) of the W-phase coil (W2) arranged on the 300 degrees. It is wired to connect the line (W phase S).

[0128] In addition, the outer printed circuit board (PCB) (44b) has end lines corresponding to the start lines of each of the U, V, W three-phase coils (U1-U2, V1-V2, W1-W2) of the inner printed circuit board (PCB) (44a), and a circular conductive pattern (446) is formed on the outer printed circuit board (PCB) (44b) to form a neutral point (COM) for Y-connection of the U, V, W three-phase coils (U1-U2, V1-V2, W1-W2) by connecting the end lines (U-phase E, V-phase E, W-phase E) of the six coils (U1-U2, V1-V2, W1-W2) in common.

[0129] Accordingly, the end wires of the U1, V1, W1, U2, V2, and W2 coils, which are sequentially arranged and assembled between the inner printed circuit board (PCB) (44a) and the outer printed circuit board (PCB) (44b), are connected to a circular conductive pattern (446) forming a common electrode (COM) to form a neutral point for Y-connection.

[0130] In the present invention, the start lines of two coils (U1-U2, V1-V2, W1-W2) of the U, V, W three-phase coil (U1-U2, V1-V2, W1-W2) are interconnected using the first to third conductive patterns (441-443) formed on the inner printed circuit board (PCB) (44a) to form a parallel circuit, and the end lines of the U, V, W three-phase coils (U1-U2, V1-V2, W1-W2) are commonly connected to a circular conductive pattern (446) forming a common electrode (COM) on the outer printed circuit board (PCB) (44b), thereby easily implementing a neutral point for Y-connection of the U, V, W three-phase coils (U1-U2, V1-V2, W1-W2).

[0131] The inner printed circuit board (PCB) (44a) above has six protrusions (444) protruding to support one side of the six bobbins (43) and to fix six inner protrusions (43e) provided on the bobbins, and the outer printed circuit board (PCB) (44b) also has six protrusions (445) protruding to support the other side of the six bobbins (43) and to fix six outer protrusions (43f) provided on the bobbins.

[0132] Moreover, the above motor (200) can be driven by a 6-step electric wave driving method using an inverter, for example.

[0133] The above axial gap type motor (200) can detect the rotational position of the rotor (30) by using, for example, a Hall sensor as a rotor position detection element when driven by a three-phase (U, V, W) drive method. To this end, when the rotor (30) rotates, the rotational position of the rotor (30) can be detected by a Hall sensor assembly installed on a printed circuit board (PCB). In the case of a three-phase drive method, the rotor position detection element that detects the position signal of the rotor (30) can use, for example, two or three Hall elements. The Hall sensor assembly can have a structure in which three Hall sensors and peripheral circuit elements are mounted on a printed circuit board (PCB).

[0134] Additionally, the above axial gap type motor (200) can of course use a sensorless type motor drive circuit without using a Hall sensor.

[0135] A water pump (EWP) (100) using an axial gap type electric motor according to the first embodiment is configured such that the shoe (41a) of the split core (41) of the stator assembly of the axial gap type electric motor (200) is press-assembled into the through hole (12e) of the body case (12), and then the rear end of the stator assembly is stored in the lower space, and then the upper cover is coupled to the lower side.

[0136] The water pump (EWP) (100) using an axial gap type motor according to the third embodiment of the present invention illustrated in FIG. 12 is different from the first embodiment in that the stator assembly (i.e., stator) of the axial gap type motor (200) is formed integrally with the body case (12).

[0137] The stator (40) of the axial gap type motor (200) according to the third embodiment of the present invention is first formed by forming a bobbin (43) integrally or separately on the outer periphery of each of a plurality of split cores (41) and assembling them, then winding a coil (45) on the outer periphery of the bobbin (43) and assembling a back yoke (42) on the rear end of the tooth (41c) of the split core (41).

[0138] After that, the assembly of the plurality of split cores (41), bobbin (43) and back yoke (42) is assembled between the inner printed circuit board (PCB) (44a) and the outer printed circuit board (PCB) (44b) shown in Fig. 10a to form a stator assembly.

[0139] After preparing the stator assembly as described above, it can be integrally formed during injection molding of the body case (12) using an insert molding method.

[0140] In this case, the head (41b) of the plurality of split cores (41) can be positioned so that the tip of the flat-shaped shoe (41a) is exposed to the fluid flow passage (P).

[0141] The above multiple split cores (41) may each be formed of soft magnetic powder (SMC: Soft Magnetic Composites) or may be formed by laminating multiple silicon steels.

[0142] In this case, when the plurality of split cores (41) are each made of soft magnetic powder (SMC: Soft Magnetic Composites), the split cores (41) compression-molded with the soft magnetic powder (SMC) do not form rust when in contact with water. Therefore, the shoe (41a) of the plurality of split cores (41) is positioned in the partition wall (12d) of the body case (12) so that it is exposed to the fluid flow passage (P).

[0143] However, when the plurality of split cores (41) are each formed by laminating a plurality of silicon steels, the split cores (41) made of silicon steel may form rust when in contact with water. Therefore, in this case, after the shoes (41a) of the plurality of split cores (41) are positioned so that they are exposed to the fluid flow passage (P) at positions corresponding to the plurality of split cores (41) on the partition wall (12d) of the body case (12), a waterproof sealing treatment may be performed by coating a thin film of epoxy or urethane so that the exposed shoes (41a) and the partition wall (12d) form the same plane.

[0144] In addition, the body case (12) surrounding the stator (40) may preferably be formed of an insulating heat-dissipating composite material having both heat dissipation and insulation performance. In this case, the molding material surrounding the stator (40) may also be made of general plastic.

[0145] It is preferable that the above stator (40) has an insulation performance of at least 10Kv or more, and considering the heat dissipation characteristics, it is preferable that the thermal conductivity is 3W / mK or more.

[0146] Considering the above, the insulating heat-dissipating composite used in the present invention may include a polymer matrix that acts as a binder and has a continuous use temperature of 150°C or higher, an insulating heat-dissipating filler made of ceramic added and dispersed to improve thermal conductivity, and reinforcing fibers added to reinforce strength.

[0147] The above polymer matrix may include one compound selected from the group consisting of polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES), polyether imide (PEI), and polyimide, or a mixture or copolymer of two or more compounds.

[0148] In this case, it is preferable that the polymer matrix has a continuous use temperature of 150°C or higher, and for example, polyphenylene sulfide (PPS) can be used.

[0149] Additionally, the insulating heat-dissipating filler may be provided in an amount of 75 to 100 parts by weight per 100 parts by weight of the polymer matrix.

[0150] In addition, the insulating heat-dissipating filler may include at least one selected from the group consisting of magnesium oxide, talc, titanium dioxide, aluminum nitride, silicon nitride, boron nitride, aluminum oxide, silica, zinc oxide, barium titanate, strontium titanate, beryllium oxide, silicon carbide, and manganese oxide.

[0151] The average particle diameter of the above insulating heat-dissipating filler may be 10 nm to 600 μm.

[0152] Moreover, the reinforcing fiber may be provided in an amount of about 30 parts by weight per 100 parts by weight of the polymer matrix, and for example, glass fiber may be used.

[0153] Additionally, the insulating composite may further include one or more additives selected from the group consisting of dispersants, antioxidants, workability improvers, coupling agents, stabilizers, flame retardants, pigments, and impact improvers.

[0154] The insulating composite material described above can be a heat-curable plastic material called BMC (Bulk Molding Compound). BMC is manufactured by first uniformly mixing (compounding) unsaturated polyester resin and fillers using a kneader, then secondarily impregnating the raw material with 6mm glass fibers and aging the resulting raw material for a certain period of time.

[0155] At the lower part of the above stator (40), a printed circuit board (PCB) (50) for a driver for applying a driving signal to the three-phase coil (45) of the stator (40) to generate a rotating magnetic field, as in the third embodiment shown in FIG. 12, may be installed. In the second embodiment shown in FIG. 11, the driver is omitted for slimming purposes, and the driver may be installed externally.

[0156] As described above, the axial gap type electric motor (200) for the water pump (100) according to the present invention can be formed or assembled integrally with the bulkhead (12d) of the body case (12) partially or entirely so that the stator (40) is completely separated from the fluid flow passage (P) inside the pump cover (11), and further, the lower part of the stator (40) is arranged in the lower space inside when coupled to the lower part of the body case (12) using the upper cover, and the rotor (30) is formed integrally with the impeller (20) and arranged in the fluid flow passage (P), and the stator (40) and the rotor (30) have a waterproofly separated structure.

[0157] When a water pump control signal is applied to the driver from a water pump (100) control device inside a vehicle, the driver applies a driving signal to a plurality of coils (45) of the axial gap type motor (200) from the driver when receiving a position signal of the rotor (30) from a hall sensor (not shown), and the stator (40) generates a rotating magnetic field from the plurality of coils (45).

[0158] When a rotating magnetic field is generated from a plurality of coils (45) of the stator (40), the rotor (30) placed in the fluid flow passage (P) rotates around the support shaft (60) together with the impeller (20), and as a result, cooling water is introduced from the inlet (11a) of the pump cover (11) according to the rotation of the impeller (20), and the introduced cooling water is discharged to the outlet (11b) along the fluid flow passage (P).

[0159] In the present invention, the impeller (20) and the rotor (30) disposed inside the fluid flow passage (P) are driven by the stator (40) of the electric motor (200) disposed outside the fluid flow passage (P) in a magnetic coupling manner, thereby realizing complete waterproofing of the stator (40) of the electric motor (200).

[0160] Moreover, in the present invention, since the stator (40) of the electric motor (200) is completely isolated from the fluid flow passage (P), a separate waterproofing treatment can be omitted, and thus the air gap between the rotor (30) and the stator (40) of the electric motor (200) can be set to an optimal state, thereby improving the efficiency of the electric motor (200).

[0161] As described above, in the present invention, a coil (45) is wound around a bobbin (43) integrally formed around the outer periphery of a plurality of split cores (41) formed of soft magnetic powder (SMC: Soft Magnetic Composites) or formed by laminating a plurality of silicon steels, and then an insulating heat-dissipating composite material made of BMC (Bulk Molding Compound) having a heat-dissipating effect is used to form an integral stator, thereby preventing moisture penetration.

[0162] In addition, by combining inner and outer printed circuit boards (PCBs) (44a, 44b) for coil wiring and a back yoke (42) that functions as a magnetic circuit to the teeth (41c) of the split core (41) protruding from the rear of the bobbin (43), a stator or a stator assembly is prepared, and the shoe (41a) portion of the split core (41) is set to be exposed to the fluid flow passage (P), thereby minimizing the air gap and minimizing the occurrence of magnetic flux leakage, thereby increasing the efficiency of the motor, and making it possible to implement complete waterproofing while significantly reducing the overall height of the pump.

[0163] In addition, in the present invention, the overall height of the water pump (100) can be significantly reduced by using the inner and / or outer printed circuit boards (PCBs) (44a, 44b) for three-phase coil wiring separately on the side of the bobbin (43) or the outer or inner side of the back yoke (42).

[0164] In this case, if the size of the inner or outer diameter is sufficient, only one of the inner and outer printed circuit boards (PCB) (44a, 44b) can be used.

[0165] Furthermore, in the present invention, a coil (45) is wound around a bobbin (43) integrally formed on the outer periphery of a plurality of split cores (41), and then an integral stator is formed by insert molding using an insulating heat-dissipating composite material made of BMC or plastic having a heat-dissipating effect. Then, in order to reduce the overall size, an inner and / or outer printed circuit board (PCB) (44a, 44b) for coil wiring is arranged separately on the inner and outer sides to perform coil wiring.

[0166] In the case of the third embodiment having a driver printed circuit board (PCB) (50) having a motor drive circuit implemented at the lower portion of the stator (40), a connection pin may be used between the inner and / or outer printed circuit boards (PCBs) (44a, 44b) for coil wiring and the driver printed circuit board (PCB) (50), and a power terminal pin (55c) may be used to connect between the driver printed circuit board (PCB) (50) and the connector housing (13a).

[0167] In addition, in the case of the second embodiment in which a printed circuit board (PCB) (50) for a driver is not provided at the lower portion of the stator (40), a power terminal pin (55c) can be used to connect between the inner printed circuit board (PCB) (44a) for coil wiring and the connector housing (13a).

[0168] In addition, in the present invention, a coil (45) is wound around a bobbin (43) integrally formed on the outer periphery of a plurality of split cores (41), and then an insulating heat-dissipating composite material made of BMC or plastic having a heat-dissipating effect is used to insert-mold the body case (12), thereby integrating the body case (12) and the stator (40), thereby significantly reducing the overall height of the water pump (100) while achieving complete waterproofing.

[0169] Although the present invention has been described and illustrated with specific preferred embodiments as examples, the present invention is not limited to the above embodiments, and various changes and modifications may be made by a person having ordinary skill in the art to which the invention pertains within a scope that does not depart from the spirit of the present invention.

[0170] The present invention relates to an axial gap type electric motor having an integral stator core, and in particular, the electric motor can be applied to a water pump (EWP), compressor, oil pump, etc. for cooling devices that circulate coolant for electrical components, batteries, fuel cell stacks, etc., which are applied to hybrid, electric, and fuel cell vehicles.

Claims

1. A rotor rotatably supported in a fluid flow passage between the pump cover and the body case; and It includes a stator formed integrally with the above body case to generate a rotating magnetic field and drive the rotor to rotate; The above stator A plurality of split cores, each of which has a cross-section in the shape of the letter “T”; A plurality of bobbins formed on the outer periphery of each of the plurality of split cores; U, V, W three-phase coils wound on the outer periphery of the above plurality of bobbins; A back yoke having a plurality of through holes arranged in an annular shape, the through holes being joined to the rear ends of the teeth of the plurality of split cores; An inner printed circuit board (PCB) on which the parallel circuit wiring of the above U, V, and W three-phase coils is formed; and It includes an outer printed circuit board (PCB) for forming a neutral point for Y-connection of the above U, V, W three-phase coil; An axial gap type electric motor for a water pump (EWP), wherein each of the plurality of bobbins, each of which has the U, V, W three-phase coils wound on it, has both ends fixed to the inner printed circuit board (PCB) and the outer printed circuit board (PCB).

2. In paragraph 1, The above stator is an axial gap type motor for a water pump (EWP) in which each shoe of the plurality of split cores is exposed to the fluid flow passage.

3. In paragraph 1, The above U, V, W three-phase coils form a parallel circuit by connecting the start lines of multiple coils assigned to each of the U, V, and W phases, and form a neutral point (COM) for Y-connection by connecting the end lines of the multiple coils in common. The above inner printed circuit board (PCB) includes first to third conductive patterns for commonly connecting the start lines of a plurality of coils assigned to each of U, V, and W phases, The above outer printed circuit board (PCB) is an axial gap type motor for a water pump (EWP) including a circular conductive pattern to which all end wires of a plurality of coils assigned to each of the U, V, and W phases are commonly connected.

4. In paragraph 3, An axial gap type motor for a water pump (EWP) further comprising U, V, W power terminal pins, each end of which is connected to the first to third conductive patterns so as to be connected to the U, V, W three-phase output terminals of an inverter circuit through a connector housing.

5. A rotor rotatably supported in the fluid flow passage between the pump cover and the body case; A stator arranged in a lower space formed by the body case and the upper cover to generate a rotating magnetic field and drive the rotor to rotate; and A bulkhead is disposed on the upper part of the body case to separate the rotor and the stator; The above stator Multiple split cores; A plurality of bobbins formed on the outer periphery of each of the plurality of split cores; U, V, W three-phase coils wound on the outer periphery of the above plurality of bobbins; A back yoke having a plurality of through holes arranged in an annular shape, the through holes being joined to the rear ends of the teeth of the plurality of split cores; An inner printed circuit board (PCB) on which the parallel circuit wiring of the above U, V, and W three-phase coils is formed; and It includes an outer printed circuit board (PCB) for forming a Y-connection of the above U, V, W three-phase coils; An axial gap type electric motor for a water pump (EWP), wherein each of the plurality of bobbins, each of which has the U, V, W three-phase coils wound on it, has both ends fixed to the inner printed circuit board (PCB) and the outer printed circuit board (PCB).

6. In paragraph 5, The above stator is an axial gap type motor for a water pump (EWP) in which the plurality of split cores are press-fitted into through holes formed in the bulkhead and each shoe is exposed to the fluid flow passage.

7. In paragraph 5, The bulkhead of the above body case has a plurality of through holes at positions corresponding to the plurality of split cores, An axial gap type motor for an electric water pump (EWP), wherein the heads of the plurality of split cores coupled to the plurality of through holes are positioned so that the shoes are exposed to the fluid flow passage, and the split cores are made of a soft magnetic powder (SMC).

8. In paragraph 5, The bulkhead of the above body case has a plurality of through holes at positions corresponding to the plurality of split cores, An axial gap type electric motor for a water pump (EWP), wherein the heads of the plurality of split cores coupled to the plurality of through holes are positioned so that the shoes are exposed to the fluid flow passage, the split cores are formed by laminating silicon steel, and the exposed shoes and the bulkheads are waterproof-sealed to form the same plane.

9. A pump housing having a pump cover having an inlet for introducing fluid and an outlet for discharging the introduced fluid, and a body case coupled to the lower portion of the pump cover to form a fluid flow passage between the inlet and the outlet; A rotor rotatably supported in the above fluid flow passage; An impeller formed integrally with the rotor on the upper side of the rotor; and It includes a stator formed integrally with the above body case to generate a rotating magnetic field and drive the rotor to rotate; The above stator A plurality of split cores, each of which has a cross-section in the shape of the letter “T”; A plurality of bobbins formed on the outer periphery of each of the plurality of split cores; U, V, W three-phase coils wound on the outer periphery of the above plurality of bobbins; A back yoke having a plurality of through holes arranged in an annular shape, the through holes being joined to the rear ends of the teeth of the plurality of split cores; An inner printed circuit board (PCB) on which the parallel circuit wiring of the above U, V, and W three-phase coils is formed; and It includes an outer printed circuit board (PCB) for forming a neutral point for Y-connection of the above U, V, W three-phase coil; An axial gap type electric motor for a water pump (EWP), wherein the plurality of bobbins, each of which has the U, V, W three-phase coils wound on them, are fixed at both ends between the inner printed circuit board (PCB) and the outer printed circuit board (PCB).

10. In paragraph 9, The above stator is a water pump in which each shoe of the plurality of split cores is exposed to the fluid flow passage, and the split cores are made of a magnetic powder (SMC).

11. In paragraph 9, A water pump in which the plurality of split cores are formed integrally with a baffle for separating the rotor and the stator, and each of the plurality of split cores is positioned on the upper portion of the body case so that the shoe portion of the head is exposed to the fluid flow passage.

12. In paragraph 9, It further includes a driver printed circuit board (PCB) mounted on the lower side of the stator and having a motor drive circuit for applying a motor drive signal to the U, V, W three-phase coils of the stator; A water pump in which a plurality of connection pins are used to electrically connect between the inner printed circuit board and the driver printed circuit board, and a plurality of power terminal pins are used to connect between the driver printed circuit board and the connector housing.

13. In paragraph 9, The above U, V, W three-phase coils form a parallel circuit by connecting the start lines of multiple coils assigned to each of the U, V, and W phases, and form a neutral point (COM) for Y-connection by connecting the end lines of the multiple coils in common. The above inner printed circuit board (PCB) includes first to third conductive patterns for commonly connecting the start lines of a plurality of coils assigned to each of U, V, and W phases, A water pump in which the above outer printed circuit board (PCB) includes a circular conductive pattern to which all end wires of a plurality of coils assigned to each of the U, V, and W phases are commonly connected.

14. In paragraph 9, A support shaft receiving portion formed extending downwardly in the central portion of a bulkhead formed on the upper portion of the above body case; A support shaft having a lower portion fixed to the center of the support shaft receiving portion and a hollow portion with a screw tab formed inside; A rotor support for integrating an impeller into the upper portion of the rotor; A bearing housing formed by protruding downwardly in the central portion of the rotor support; and A water pump further comprising a sleeve bearing installed inside the bearing housing and rotatably supporting the rotor and impeller about the support shaft.

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