KR102347870B1 - Axial Gap Type Electric Motor and Electric Water Pump Using the Same - Google Patents

Abstract

The present invention relates to an axial gap type electric motor employing a non-rare earth magnet and a water pump using the same.
An axial gap type electric motor for a water pump (EWP) of the present invention includes 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 the upper cover to generate a rotating magnetic field to rotate and drive the rotor; and a partition wall disposed on the body case to separate the rotor and the stator, wherein the rotor includes a non-rare earth magnet.

Description

Axial Gap Type Electric Motor and Electric Water Pump Using the Same

The present invention relates to an axial gap type electric motor, and more particularly, to an axial gap type electric motor employing a non-rare earth magnet and an electric water pump using the same.

In general, a water pump applied to a vehicle is a device that circulates coolant, and is driven by a belt to rotate a pump impeller to suck and discharge coolant to circulate the coolant, An engine-driven water pump having a seal unit assembled therein to prevent leakage of coolant, an electric motor is driven by electricity supplied from a battery, etc., and the impeller rotates by the electric motor to supply coolant An electric water pump that circulates cooling water by suction and discharge is typically used.

Among them, since the electric water pump does not require engine driving force of a vehicle compared to the engine-driven water pump, engine efficiency is increased compared to the engine-driven water pump, and thus fuel efficiency is improved. Furthermore, since it provides the advantage of precisely controlling the temperature of the coolant, it has been widely applied to various vehicle models.

In addition, in the case of an electric vehicle, a hybrid vehicle, or a fuel cell vehicle, a situation in which driving is performed with the engine stopped (in the case of a hybrid vehicle), or even a situation in which an engine to drive a water pump is not provided (electric vehicle, In the case of a fuel cell vehicle), the importance of the electric water pump is increasing as compared to the engine-driven water pump.

On the other hand, among the electric water pumps, the canned type electric water pump is a pump driven by an electric motor having a can-shaped sealing container inside a stator, and a rotor and The can structure is inserted between the stators and the hydraulic power unit is extended to the rotor part so that the rotor is immersed in the cooling water, so that the input water cools the frictional heat generated in the rotor appropriately.

Korean Patent Registration No. 10-0900120 (Patent Document 1) discloses a pump unit having an impeller for sucking and discharging liquid, a motor unit driving the pump unit, a casing containing the pump unit, the motor unit and the A pump including a partition plate for isolating a pump unit and a mold resin integrally molded with the motor unit to protect the motor unit has been proposed.

The conventional pump structure of Patent Document 1 has a structure in which the magnet and the state core are positioned in the radial direction so that water flows into the magnet. It has a waterproof structure using (Can) or injection molding. As a result, the air gap between the rotor and the stator core increases and magnetic flux loss occurs a lot, making it difficult to match the desired pump (motor) capacity with general magnets, so expensive rare earth magnets are generally used. are doing

In general, inner rotor type internal motors are used for water pumps (EWP), compressors, and oil pumps. is implemented, so the unit price is high.

In addition, the motor for water pump is an inner rotor type motor, and the rare earth magnet (Nd-Fe-B) used in the rotor contains iron, so there is a problem that the magnet rusts when it comes into contact with water, so the rotor part is also waterproof. is hiring Therefore, the motor for the water pump has a structure in which the air gap between the rotor and the stator becomes large, so that the amount of Nd used by the rotor magnet is inevitably increased.

Furthermore, in the inner rotor type motor, the inner shoe portion of the stator core opposite to the rotor magnet is generally not “rounded” (R), so the back electromotive force (EMF) waveform is sine. ) There is a problem with noise and vibration because it cannot be made into a curved line. That is, in general, the inner side of the core is designed to form a concentric circle with respect to the center. Therefore, the core structure of the conventional stator requires an auxiliary part or design for improving the noise and vibration problems separately.

In order to improve such vibration and noise generation, in the prior art, it is generally performed in the form of giving “R” to the magnet of the rotor. However, if the magnet has a segment structure, there is no problem, but in the case of an integrated structure in which the magnet is divided and magnetized, it is impossible to form “R”.

On the other hand, the conventional motor for water pump is grounded between the core of the stator and the printed circuit board (PCB) on which the motor driving circuit is mounted. There is a problem that should be added.

: Korean Patent Publication No. 10-0900120

The present invention was devised in view of these conventional problems, and its purpose is to reduce the air gap by separating using a thin plate partition between the rotor and the stator. An object of the present invention is to provide an axial gap type electric motor having magnetic energy equivalent to that of an electric motor using a magnet and a water pump using the same.

Another object of the present invention is to provide an axial gap type electric motor that is designed for waterproofing with a simple structure and can be completely waterproofed, and a water pump using the same.

Another object of the present invention is to apply SMC (Soft Magnetic Composites) instead of general electrical steel sheet (S-60) to the stator core (teeth) of the longitudinal motor to minimize the core loss generated in the motor. It is to provide an axial gap type electric motor optimized for , and a water pump using the same.

Another object of the present invention is to form “R” in the shape of the core (teeth) by manufacturing the teeth of the stator core by a compression molding method using SMC (Soft Magnetic Composites) powder to convert the Back EMF (Electromotive Force) waveform into a sine curve. curve) to provide an axial gap type electric motor capable of improving noise and vibration generation and a water pump using the same.

According to an embodiment of the present invention, an axial gap type electric motor for a water pump (EWP) includes 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 the upper cover to generate a rotating magnetic field to rotate and drive the rotor; and a partition wall disposed on the body case to separate the rotor and the stator, wherein the rotor includes a non-rare earth magnet.

The rotor includes a plurality of magnets arranged in an annular shape; and a back yoke installed on the rear surface of the magnet to form a magnetic circuit, wherein the rotor is integrally formed under the impeller and rotatably supported on a support shaft having one end supported by the partition wall.

In this case, the partition wall serves as an air gap between the rotor and the stator.

In addition, the axial gap type electric motor for a water pump (EWP) according to an embodiment of the present invention includes a sleeve bearing coupled to the outer periphery of the support shaft to rotatably support the rotor; and a bearing housing integrally formed with the lower plate of the impeller to accommodate the sleeve bearing therein.

The stator may include: a stator core having a plurality of teeth and a back yoke interconnected with the plurality of teeth to form a magnetic circuit; a plurality of bobbins made of an insulating material integrally formed so as to surround an outer circumferential surface around which coils of each of the plurality of teeth are to be wound; and a coil wound around the outer circumferential surface of the bobbin, wherein each of the plurality of teeth has a “T” shape and is made of Soft Magnetic Composites (SMC), and the back yoke includes a plurality of electrical steel plates. It may be formed by stacking.

In addition, each of the plurality of teeth may include a coil winding unit on which the coil is wound; and a shoe having a flange extending from the coil winding unit, wherein an edge between the side surface and the tip surface of the shoe and the tip surface of the shoe may be "rounded (R)" processed.

Furthermore, the coil winding portion may be formed of a triangular pole, and the shoe may have a trapezoidal cross-section.

The stator core may include a plurality of teeth arranged in an annular shape on the same circumference and parallel to the axial direction so as to face the magnets of the rotor; and a back yoke connected to the plurality of teeth at right angles to form a magnetic circuit.

In this case, the plurality of teeth may be press-fitted to the assembly hole or assembly groove of the back yoke, respectively.

In the stator, a plurality of teeth are arranged in an annular shape parallel to the axial direction on the same circumference to face the magnet of the rotor, and the plurality of teeth are connected at right angles to the back yoke to form a magnetic circuit. can be provided

A water pump according to an embodiment of the present invention includes: a pump cover having an inlet through which a fluid is introduced and an outlet through which the introduced fluid is discharged; a body case coupled to the pump cover to form a fluid flow passage inside the pump cover and having a lower space; an upper cover coupled to the lower end of the body case to set the lower space to a sealing state; a rotor rotatably supported in the fluid flow passage; an impeller integrally formed with the rotor on the upper side of the rotor; a stator disposed in the lower space to generate a rotating magnetic field to rotate and drive the rotor; and a partition wall disposed on the body case to separate the rotor and the stator, wherein the rotor and the stator form an axial gap type electric motor.

In addition, the water pump according to an embodiment of the present invention includes: a pump housing having a space in a sealed state on one side, and an inlet through which a fluid is introduced and an outlet through which the introduced fluid is discharged are connected through a fluid flow passage; a rotor rotatably supported in the fluid flow passage; an impeller integrally formed with the rotor on the upper side of the rotor; a stator disposed in the lower space to generate a rotating magnetic field to rotate and drive the rotor; a partition wall disposed inside the pump housing to separate the rotor and the stator; and a support shaft rotatably supporting the rotor, one end supported by the partition wall, wherein the rotor and the stator form an axial gap type electric motor, and the rotor may include a non-rare earth magnet.

the stator includes a stator core each having a plurality of teeth on which a coil is wound and a back yoke connected to the plurality of teeth at right angles to form a magnetic circuit; Each of the plurality of teeth may be made of Soft Magnetic Composites (SMC), and the back yoke may be made of an electrical steel sheet.

In this case, each of the plurality of teeth has a flange extending from the coil winding portion of the shoe facing the rotor, and the edge between the side surface and the tip surface of the shoe may be “rounded (R)”.

In addition, the rotor may include a ferrite (Ferrite) magnet.

Further, in the stator, a plurality of teeth are annularly arranged on the same circumference and parallel to the axial direction so as to face the magnet of the rotor, and the plurality of teeth are connected to the back yoke at right angles to form a magnetic circuit. It has a core, and the teeth may be compression molded or extrusion molded by any one of an amorphous metal powder, a spherical soft magnetic powder, or an alloy powder mixed with an amorphous metal powder and a spherical soft magnetic powder.

A water pump according to an embodiment of the present invention includes a bearing coupled to an outer periphery of the support shaft to rotatably support the rotor; and a bearing housing integrally formed with the lower plate of the impeller to accommodate the bearing therein.

As described above, in the axial gap type motor of the present invention, when a longitudinal motor having the same outer diameter as a general internal type motor is applied, the separation using a thin plate partition wall between the rotor and the stator causes an air gap It is possible to reduce the , so that even if a ferrite magnet, which is a non-rare earth magnet, is used, it has the same magnetic energy as an electric motor using a rare earth magnet containing Nd.

In the present invention, it is designed with a simple structure by separating the rotor and the stator by the bulkhead of the body case in which the stator is embedded, so that it can be completely waterproofed.

In addition, in the present invention, as the rotor and the stator are separated by using a thin plate partition, a ferrite magnet, which is an inexpensive non-rare earth magnet, may be used as the magnet of the rotor.

Furthermore, the electric motor of the present invention is an axial gap type in which the rotor and the stator face each other with a thin plate barrier therebetween. Accordingly, it is possible to increase the efficiency of the motor by further reducing the air gap compared to the conventional motor employing the rare earth magnet.

In the present invention, the stator core (teeth) of the longitudinal motor applies SMC (Soft Magnetic Composites) instead of the general electrical steel plate (S-60) to optimize the core (teeth) shape to minimize the iron loss generated in the motor. .

In addition, in the present invention, by forming a stator core (teeth) by a compression molding method using SMC (Soft Magnetic Composites) powder, an “R” is formed in the shape of the core (teeth) to convert the Back EMF (Electromotive Force) waveform to a sine curve. curve) to improve noise and vibration generation.

1 is a front view of a water pump using an axial gap type electric motor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 .
3 is an exploded perspective view for each assembly of a water pump using an axial gap type electric motor according to an embodiment of the present invention.
4 is an exploded perspective view of a water pump using an axial gap type electric motor according to an embodiment of the present invention.
5 is a perspective view of an axial gap type electric motor according to an embodiment of the present invention.
6 is an axial cross-sectional view illustrating a complete waterproof structure between a stator and a rotor by installing a bulkhead at the upper end of a body case in a water pump using an axial gap type electric motor according to an embodiment of the present invention.
7A to 7D are views showing the coupling relationship between the teeth of the stator core and the back yoke according to the first embodiment in the axial gap type electric motor of the present invention, respectively, a plan view of the stator core, a plan view of the back yoke, and FIG. 7A The BB line shows a cross-sectional view and a perspective view.
8A to 8D are views showing the coupling relationship between the teeth of the stator core and the back yoke according to the second embodiment in the axial gap type electric motor of the present invention, respectively, a plan view of the stator core, a plan view of the back yoke, and FIG. 8A CC line shows a cross-sectional view and a perspective view.
9A to 9D are views showing the coupling relationship between the teeth and the back yoke of the stator core according to the third embodiment in the axial gap type electric motor of the present invention, respectively, a plan view of the stator core, a plan view of the back yoke, and FIG. 9A DD line shows a cross-sectional view and a perspective view.
10A to 10D are views showing the coupling relationship between the teeth of the stator core and the back yoke according to the fourth embodiment in the axial gap type electric motor of the present invention, respectively, a plan view of the stator core, a plan view of the back yoke, and FIG. 10A The EE line shows a cross-sectional view and a perspective view.
11A to 11D are views showing the coupling relationship between the teeth of the stator core and the back yoke according to the fifth embodiment in the axial gap type electric motor of the present invention, respectively, a plan view of the stator core, a plan view of the back yoke, and FIG. 11A FF line shows a cross-sectional view and a perspective view.
12A and 12B show a square wave back EMF waveform obtained when the inner shoe portion of the stator core is not treated with “R” in a conventional internal electric motor, and a sine wave form obtained in an axial gap type motor according to the present invention, respectively. It is a diagram showing the Back EMF waveform of

Hereinafter, preferred embodiments according to the present invention will be described with reference to the accompanying drawings.

In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. Definitions of these terms should be made based on the content throughout this specification.

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

1 to 6 , a water pump (EWP) 200 using an axial gap type electric motor according to the present invention is largely a pump housing 10, an axial gap type electric motor 100, an impeller 20 and A driver 50 is included.

The pump housing 10 has an inlet 11a through which a fluid, such as cooling water, is introduced in the center of one end, and an outlet 11b through which the fluid introduced at one side of the other end is discharged. The pump cover 11 is formed and the opening of the pump cover 11 is covered to form a fluid flow passage P inside the pump cover 11, and a lower space ( 14), the body case 12 made of an inverted cup shape, and the stator 40 and the stator 40 of the electric motor 100 built in the sealed lower space 14 inside the body case 12. A driver 50 for driving is built-in and includes an upper cover 13 coupled to the lower end of the body case 12 .

The pump cover 11 and the body case 12 preferably have a cylindrical shape and have a mutually fixed coupling structure.

For mutual fixed coupling between the pump cover 11 and the body case 12, for example, four fixing extensions 11c protrude, and a fixing screw or fixing bolt is fastened to the coupling hole.

In addition, between the pump cover 11 and the body case 12, a circular protrusion 11d and a circular groove 12a are formed on each flange, and an O-ring for sealing (12a) is formed in the groove (12a). 63) is inserted.

Furthermore, the O-ring 64 is also inserted into the coupling portion between the body case 12 and the upper cover 13 to maintain the sealing state of the lower space 14 . In addition, it is also possible to realize a more perfect sealing state by a method of bonding the coupling portion between the body case 12 and the upper cover 13 using a laser welding method.

A connector housing 13a in which a terminal terminal for applying a driving signal to the driver 50 from the outside is disposed extends from the lower surface of the upper cover 13 .

The pump cover 11 , the body case 12 , and the upper cover 13 forming the pump housing 10 may be formed using, for example, a resin such as Poly Phenylene Sulfide (PPS).

In the fluid flow passage P of the bent portion between the inlet 11a and the outlet 11b of the pump cover 11, the rotor 30 of the electric motor 100 is integrally formed on the lower side and the impeller 20 is disposed. has been

In addition, the open lower end of the pump cover 11 is extended to secure a wider space than the inlet 11a so that the impeller 20 can be disposed in the fluid flow passage P, and the opening of the pump cover 11 is At the upper portion of the body case 12 corresponding to the lower end, a flange is extended to form a concave structure.

The impeller 20 has a plurality of blades 23 between the upper plate 21 and the lower plate 22 in the form of a disk so as to discharge a fluid such as coolant flowing in from the inlet 11a through the outlet 11b disposed on the side thereof. are arranged radially. The upper plate 21 has a through hole formed in the center and has a downward beam shape that increases in diameter from the upper side to the lower side, and the lower plate 22 is composed of a circular plate surrounding the upper side and the outer side of the rotor 20 . The lower plate 22 and the rotor 20 may be integrated with the insert molding method.

In addition, a bearing housing 62 is protruded from the center of the lower plate 22 , and a sleeve bearing 61 , which rotatably supports the rotor 20 on the support shaft 60 , is installed in the bearing housing 62 . .

Considering that the sleeve bearing 61 is in contact with a fluid, it is preferable to use an oilless bearing such as a carbon bearing or a plastic bearing.

Meanwhile, in the present invention, as shown in FIGS. 2 to 6 , a core-type stator disposed in the sealed lower space 14 inside the body case 12 as a driving means for rotationally driving the impeller 20 . An axial gap type electric motor 100 including 40 and a rotor 30 disposed opposite to the stator 40 in the fluid flow passage P outside the body case 12 is employed.

First, the rotor 30 is a ring-shaped back yoke 31 and a magnet 32 are sequentially installed on the bottom surface of the lower plate 22 to constitute a single body with the impeller 20. The magnet 32 of the rotor 30 is made of a plurality of divided magnet pieces of N and S poles, or a magnet in which N and S poles are divided into multipoles in a ring-shaped magnet may be used, and the back yoke ( 31) is installed on the rear surface of the magnet 32 to form a magnetic circuit.

A partition wall 12b of a thin plate for separating the stator 40 and the rotor 30 is installed on the upper portion of the body case 12 to implement a completely waterproof structure for the stator 40 . That is, the stator 40 disposed in the sealed lower space 14 inside the body case 12 can completely block contact with water.

The barrier rib 12b is formed to have a relatively thin thickness compared to the cylindrical portion of the body case 12 so that the magnet of the rotor 30 is formed as a non-rare-earth magnet, a ferrite magnet, as will be described below. can be used

That is, the electric motor 100 of the present invention is an axial gap type in which the rotor 30 and the stator 40 face each other with the thin plate partition 12b interposed therebetween, without the need for a separate magnetic waterproof structure such as a rare earth magnet. It can be used in an open structure. That is, in the electric motor 100 according to the present invention, even if the magnet 32 of the rotor 30 is operated for a long time in a state in which the magnet 32 of the rotor 30 is in contact with the coolant flowing through the fluid flow passage P inside the pump cover 11, the performance of the magnet decreases. This does not happen. Therefore, in the electric motor 100 of the present invention, the efficiency can be increased by further reducing the air gap compared to the electric motor employing the rare earth magnet having a magnet waterproof structure.

In addition, in the present invention, when a vertical motor having the same outer diameter as a general internal type electric motor is applied, an air gap is formed between the rotor 30 and the stator 40 by using a thin plate partition 12b. It is possible to reduce , so that an axial gap type motor having the same magnetic energy as a motor using a rare earth magnet containing Nd can be implemented even when a ferrite magnet, which is a non-rare earth magnet, is used.

The support shaft 60 is integrated with an insert molding method in which a part of the support shaft 60 is inserted into the center of the partition wall 12b during injection molding of the body case 12 or It is fixed by being press-fitted to the integral support shaft accommodating part 12c formed in the central part of the partition 12b.

A part of the support shaft accommodating part 12c extends from the partition wall 12b to the lower space 14, and a part extends and protrudes upward of the partition wall 12b. The support shaft 60 has a sufficient contact area. firmly support the lower part of the

Hereinafter, a stator of an axial gap type electric motor according to an embodiment of the present invention will be described.

4 to 6, the stator 40 is installed in the lower space 14 that maintains the sealing state, and faces the rotor 30 in the axial direction with the partition wall 12b of the thin plate interposed therebetween. arranged to constitute an axial gap type motor.

The stator 40 includes a stator core 45 having a plurality of teeth 41 and a back yoke 42 that interconnects the plurality of teeth 41 to form a magnetic circuit, and the plurality of teeth 41 ) Each coil includes a plurality of bobbins 43 of an insulating material integrally formed to surround the outer circumferential surface to be wound, and a coil 44 wound around the outer circumferential surface of the bobbin 43 .

The plurality of teeth 41 forming the stator core 45 are each made in a “T” shape and may be manufactured by compression molding Soft Magnetic Composites (SMC), and the shoe portion is the rotor. The magnets of (30) are arranged in an annular shape parallel to the axial direction on the same circumference so as to face each other.

The tooth 41 is a soft magnetic powder (SMC), high magnetic permeability, low coercive force and high saturation magnetic induction isotropic magnetic material, for example, Fe-Ni, Fe-Co, Fe-Si alloy powder to be used. can If the tooth 41 is manufactured by compression molding or extrusion molding with this soft magnetic powder (SMC), it can be formed into a 3D structure, and the tooth 41 has isotropic properties.

As will be described later, the compression molding method of the teeth 41 with soft magnetic powder (SMC) is the “necessary” for forming a curved surface on the tip of the tooth 41 opposite to the magnet 32 of the rotor 30, that is, the shoe portion. It is important to be able to easily form "rounding (R)".

The tooth 41 of the present invention is formed by mixing an amorphous metal powder with high magnetic permeability and a binder in addition to compression molding of the soft magnetic powder (SMC), or an amorphous metal powder, a spherical soft magnetic powder (SMC) and a binder in a predetermined ratio. It can be molded by mixing. In this case, when 100% of the amorphous metal powder is used, when the spherical soft magnetic powder (SMC) is mixed in a predetermined ratio, the difficulty of high-pressure sintering can be solved and the magnetic permeability can be increased.

A plurality of electrical steel plates (silicon steel plates) made of thin plates are stacked on the rear end of the plurality of teeth 41 and are coupled to the plurality of teeth 41 to form a magnetic circuit. The annular back yoke has a predetermined width. (42) is arranged.

Flanges 43a and 43b are formed at both ends of each of the plurality of bobbins 43 to define an area in which the coil 44 is wound.

A conventional radial gap type electric motor uses a stator core in which a plurality of teeth are radially arranged on an inner periphery or an outer periphery of a back yoke. When stacking electrical steel sheets (silicon steel sheets) together (in a form connected to each other) with respect to the back yoke and the teeth, the core shape, especially the tip of the teeth facing the magnet of the rotor (that is, the shoe portion) ), the “rounding (R)” required to form a curved surface cannot be easily formed.

As a result, in the conventional radial gap type electric motor, a back electromotive force (EMF) waveform is obtained in the form of a square wave as shown in FIG. can't stop it from happening

The stator core 45 of the present invention is applied to an axial gap type electric motor differently from the stator core of the above-described radial gap type electric motor, and a plurality of teeth 41 and a back yoke 42 are Since the structure is connected at right angles, it is impossible to configure the plurality of teeth and the back yoke as an integrated thin plate laminate.

In order to solve this problem, in the stator core 45 of the present invention, the teeth 41 having a complex 3D shape are manufactured by compression molding soft magnetic powder (SMC), and the back yoke 42 is made of an electrical steel plate ( After preparing by punching a silicon steel sheet), it can be obtained by assembling a plurality of soft magnetic powder (SMC) teeth 41 to the back yoke 42 as shown in FIG. 7D .

The plurality of teeth 41 formed in the “T” shape are each manufactured by compression molding soft magnetic powder (SMC) to easily form “rounding (R)” in the core shape, which is an ideal sign as shown in FIG. 12B . Back Electromotive Force (S1: solid line) close to the sine curve (S2: dotted line) can be obtained (distortion factor: 0.5%), and as a result, noise and vibration generated by the rotation of the motor are improved can do.

In addition, the stator core 45 of the present invention is a structure in which a plurality of teeth 41 and the back yoke 42 are connected at right angles, and is specialized for a vertical motor, and the teeth 41 of the stator core 45 are general electric The shape of the core (teeth) was optimized by introducing “rounding (R)” to the tooth shape to minimize the core loss generated in the motor by applying SMC (Soft Magnetic Composites) rather than a steel plate.

In the stator 40 according to the present invention, first, a plurality of teeth 41 are manufactured with soft magnetic powder (SMC), and a plurality of electrical steel sheets (silicon steel sheets) are punched to form an annular back yoke having a predetermined width ( 42) is prepared.

Subsequently, the bobbin 43 is integrally formed on the teeth 41 by insert-molding each of the plurality of teeth 41 with thermosetting resin of an insulating material, thereby defining an area in which the coil is to be wound.

After that, the coil 44 is wound on the bobbin 43 integrally formed on the teeth 41, and one end of the teeth 41 is coupled to the assembly hole 42b of the back yoke 42, as shown in FIG. 7D. The assembly of the stator 40 is completed.

In the winding of the coil 44 with respect to the bobbin 43 , first, the coil 44 may be wound in a state in which the teeth 41 in which the bobbin is integrally formed are coupled to the back yoke 42 .

A driver 50 for generating a rotating magnetic field by applying a driving signal to the three-phase coil of the stator 40 is installed under the stator 40 . The driver 50 includes a printed circuit board (PCB) 51 on which various electronic components 54 forming a motor driving circuit are mounted.

A plurality of, for example, three protrusions 52 are formed to extend on the outer periphery of the printed circuit board (PCB) 51 , and a printed circuit board (PCB) 51 is formed on each of the three protrusions 52 , respectively. A through hole for fixing using a fixing screw or a fixing bolt 53 is formed in the fixing portion 12d installed inside the case 12 .

The back yoke 42 located on the upper side of the printed circuit board (PCB) 51 is also formed with three protrusions 42c extending in a portion corresponding to the three protrusions 52 of the printed circuit board (PCB) 51 , And, each protrusion (42c) is formed with a through hole through which the fixing screw or the fixing bolt (53) is fastened to the fixing portion (12d).

The stator core 41 of the present invention can be variously modified according to the assembly structure of the soft magnetic powder (SMC) teeth 41 and the back yoke 42, as will be described below with reference to FIGS. 7A to 11D. .

7A to 7D , the stator core 45 according to the first embodiment of the present invention includes nine soft magnetic powder (SMC) teeth 41 and a back yoke 42 .

The tooth 41 is made in a "T" shape by compression molding of soft magnetic powder (SMC), and the tip portion opposite to the magnet of the rotor, that is, the shoe 41a, is a coil winding portion ( 41b) has a structure in which the flange is extended.

The coil winding portion 41b has an approximately triangular pole, and the shoe 41a has an approximately tetragonal pole. The shoe 41a and the coil winding portion 41b have a substantially trapezoidal cross-section, and the edge of the shoe 41a and the coil winding portion 41b, which is the boundary between each surface and the surface, is treated with “rounding (R)” to have a curved surface. is formed with

Therefore, in the electric motor employing the stator core 45 according to the first embodiment, a back EMF (Back Electromotive Force) waveform S1 close to an ideal sine curve S2 is obtained as shown in FIG. 12B. (distortion rate: 0.5%), and as a result, noise and vibration generation according to the rotation of the motor can be improved, and core loss generated from the motor can be minimized.

In the stator core 45 according to the first embodiment of the present invention, nine teeth 41 are assembled to a back yoke 42 having nine assembly holes 42b.

The back yoke 42 is obtained by punching and laminating a plurality of electrical steel sheets (silicon steel sheets), and a central portion to form a ring shape having a predetermined width to serve as a magnetic circuit path between adjacent teeth 41 The through hole 42a is formed in the , and nine assembly holes 42b are formed on the same circumference.

The back yoke 42 has three protrusions 42c extending on the outer periphery, and a through hole is formed in each protrusion 42c. It is fixed using the fixing bolt 53 at (12d).

The stator core 45 according to the first embodiment of the present invention has a structure in which the nine teeth 41 are press-fitted or fixed on the same line when the nine teeth 41 are assembled into the nine assembly holes 42b of the back yoke 42 . can be adopted, in this case the stopper (stopper) role can be the bobbin 43 is wound coil 44.

8A to 8D , the stator core 45a according to the second embodiment of the present invention includes nine soft magnetic powder (SMC) teeth 41 and a back yoke 421 .

The nine soft magnetic powder (SMC) teeth 41 in the stator core 45a according to the second embodiment are the same as those of the first embodiment, except for the back yoke 421 .

The back yoke 421 has a through hole 42a formed in the center to form a ring shape having a predetermined width to serve as a magnetic circuit path between the adjacent teeth 41, and nine assembly grooves ( 421b) is formed.

The back yoke 421 according to the second embodiment has a through hole formed in a portion forming the assembly groove 421b, and an electrical steel sheet (silicon steel sheet) is additionally laminated on the lower side of the assembly groove 421b to be completed. can

The stator core 45a according to the second embodiment of the present invention can adopt a structure in which the nine teeth 41 are press-fitted when assembling the nine assembling grooves 421b of the back yoke 421, In this case, the bobbin 43 on which the coil 44 is wound may serve as a stopper.

As a result, when one end of the teeth 41 is assembled into the assembly groove 421b of the back yoke 421, the contact area between the teeth 41 and the back yoke 421 increases compared to the first embodiment. do.

Accordingly, the stator core 45 according to the second embodiment of the present invention is wound on the teeth 41 as the contact area between the nine soft magnetic powder (SMC) teeth 41 and the back yoke 421 increases. When heat is generated from the coil 44, heat is rapidly dissipated from the teeth 41 through the back yoke 421 having a large area, so that it has a better heat dissipation function than that of the first embodiment.

In the stator core 45a according to the second embodiment of the present invention, the configuration of the soft magnetic powder (SMC) teeth 41 except for the back yoke 421 is the same as that of the first embodiment, the shoe 41a and the coil winding. Each surface of the portion 41b and the edge, which is the boundary portion of the surface, are formed into a curved surface by processing "rounding (R)".

Therefore, the stator core 45a according to the second embodiment is treated with “rounding (R)” at the edge, which is the boundary between each surface, and is close to an ideal sine curve (S2) as shown in FIG. 12B. It is possible to obtain a back electromotive force (EMF) waveform S1 (distortion factor: 0.5%), and as a result, noise and vibration generation according to the rotation of the motor can be improved, and also, the core loss generated in the motor ) can be minimized.

9A to 9D , the stator core 45b according to the third embodiment of the present invention includes nine soft magnetic powder (SMC) teeth 411 and a back yoke 421 .

In the stator core 45b according to the third embodiment, the back yoke 421 is the same as that of the second embodiment, except for nine soft magnetic powder (SMC) teeth 411 .

The tooth 411 is made in a "T" shape by compression molding of soft magnetic powder (SMC), and the tip portion opposite to the magnet of the rotor, that is, the shoe 411a, is a coil winding portion ( 41b) has a structure in which the flange is extended.

The coil winding portion 41b forming the tooth 411 has an approximately triangular pole, the shoe 411a has an approximately quadrangular pole, and the shoe 411a has an approximately trapezoidal cross-section, and the shoe 411a and the edge of the coil winding portion 41b, which is the boundary between each surface, is formed into a curved surface by processing “rounding (R). In addition, the shoe 411a facing the magnet of the rotor is as shown in FIG. 9c . Similarly, the front-end|tip has comprised the curved-surface shape.

Therefore, the stator core 45b according to the third embodiment is treated with “rounding (R)” at the edge, which is the boundary between each surface, and is close to the ideal sine curve (S2) as shown in FIG. 12B. It is possible to obtain a back electromotive force (EMF) waveform S1, so that it is possible to improve the generation of noise and vibration according to the rotation of the electric motor.

In addition, the stator core 45b according to the third embodiment can minimize core loss generated in the electric motor and has an excellent heat dissipation function.

The stator core 45b according to the third embodiment of the present invention adopts a press-fitting structure when the teeth 411 are assembled into the assembly grooves 421b of the back yoke 421 in the same manner as in the second embodiment. In this case, the bobbin 43 on which the coil 44 is wound may serve as a stopper.

10A to 10D , the stator core 45c according to the fourth embodiment of the present invention includes nine soft magnetic powder (SMC) teeth 41 and a back yoke 422 .

In the stator core 45c according to the fourth embodiment, nine soft magnetic powder (SMC) teeth 41 are the same as those of the first embodiment, and the back yoke 422 is different.

In the fourth embodiment, as shown in FIG. 10B, the back yoke 422 has a through hole 42a in the center to form a ring shape with a predetermined width to serve as a magnetic circuit path between adjacent teeth 41. It is formed, and the assembly hole to which one end of the teeth 41 is assembled is not formed.

In the stator core 45c according to the fourth embodiment of the present invention, as shown in FIG. 10c , face-to-face bonding is made between nine soft magnetic powder (SMC) teeth 41 and a back yoke 422 .

Accordingly, the stator core 45c according to the fourth embodiment has a plurality of assembly slots formed on the outer periphery of the back yoke 422 for assembling between the nine soft magnetic powder (SMC) teeth 41 and the back yoke 422 . A fixing screw or a fixing bolt 53 may be fastened to the 42d to be fixed to a fixing unit provided in the body case 12 .

11A to 11D , the stator core 45d according to the fifth embodiment of the present invention includes nine soft magnetic powder (SMC) teeth 41 and a back yoke 42 .

In the stator core 45d according to the fifth embodiment, the nine soft magnetic powder (SMC) teeth 41 and the back yoke 42 are the same as in the first embodiment. The difference from the first embodiment is that a pin is attached to the back yoke 42 as shown in FIG. 11C for coupling between the back yoke 42 and the PCB 51 in order to improve EMC and EMI. 55) is installed.

Conventionally, it is configured in a way of grounding the bottom of the bearing housing or the core using a ring for grounding, so a separate connection configuration such as a jumper wire is required, which causes problems in unit cost and assembly.

In the present invention, a hole is made in the back yoke 42 and the pin 55 is press-fitted, and when the PCB 51 is assembled and the pin 55 comes out on the front side of the PCB 51 , the pin 55 is soldered to the back yoke 42 . ) and the method of interconnecting the GND of the PCB 51 can be adopted to improve EMC and EMI.

In the stator core 45 according to the present invention, when heat is generated from the coil 44 wound around the teeth 41, heat is rapidly dissipated from the teeth 41 through the back yoke 42 of a large area, and the back yoke ( 42 is a method of fixing to the body case 12 through a fixing screw or fixing bolt 53 or bonding a part of the back yoke 42 to the body case 12, as shown in FIGS. 2 and 6 . heat dissipation can be achieved.

In the above-described first to fifth embodiments, only the teeth 41 are made of soft magnetic powder (SMC), and the back yoke 42 is laminated after punching out a thin electrical steel sheet (silicon steel sheet). However, the present invention is not limited thereto, and it is of course also possible to assemble the teeth and the back yoke after manufacturing them from soft magnetic powder (SMC).

In the water pump 200 according to the present invention, the axial gap type electric motor 100 may be configured as a BLDC motor having a 10-pole-9 slot structure, for example. In addition, in the electric motor 100, when the coil 44 of the stator 40 is wound on the plurality of teeth 41, the coil 44 is wound in a U, V, W three-phase structure, and U, V, W The other end of the three-phase coil 44 may be connected in a star-connection method. Furthermore, the electric motor 100 may be driven in a 6-step radio wave driving method using, for example, an inverter.

The axial gap type electric motor 100 for the water pump 200 according to the present invention has a body case 12 in which the stator 40 is a waterproof space completely separated from the fluid flow passage P inside the pump cover 11. is disposed in the lower space 14 of the, the rotor 30 is integrally formed with the impeller 20 and is disposed in the fluid flow passage P, and the stator 40 and the rotor 30 are in the partition wall 12b It has a structure separated by

In the axial gap type electric motor 100 according to the present invention, when a water pump control signal is applied to the driver 50 from the water pump 200 control device inside the vehicle, the driver 50 is transmitted from a hall sensor (not shown). When receiving the position signal of the rotor, a driving signal is applied from the driver 50 to the stator coil 44 of the axial gap type electric motor 100, and the stator 40 has a rotating magnetic field from the plurality of teeth 41 Occurs.

When a rotating magnetic field is generated from the plurality of teeth 41 of the stator 40 , the rotor 30 disposed in the fluid flow passage P through the partition 12b moves the support shaft 60 together with the impeller 20 . The rotation is made about the center, and as a result, cooling water is introduced from the inlet 11a of the pump cover 11 according to the rotation of the impeller 43, and the introduced cooling water is introduced to the outlet 11b along the fluid flow passage P. is emitted

In the present invention, the impeller 20 and the rotor 30 disposed inside the fluid flow passage P by the stator 40 of the electric motor 100 disposed outside the fluid flow passage P are magnetically coupled. By driving, complete waterproofing of the stator 40 of the electric motor 100 can be realized.

Furthermore, in the present invention, as the stator 40 of the electric motor 100 is completely isolated from the fluid flow passage P, a separate waterproofing treatment can be omitted, and thereby the rotor 30 and the stator ( 40), the efficiency of the electric motor 100 can be improved by setting the air gap between them to an optimal state.

In addition, in the present invention, as the stator 40 of the motor is completely isolated from the fluid flow passage P, it is possible to support the support shaft 60 of the motor with a general bearing that does not employ a waterproof structure, thereby reducing costs. Durability can be improved.

In the present invention, by applying a longitudinal motor having the same outer diameter as an internal motor, even if a ferrite magnet, which is a non-rare earth magnet, is used, it can have the same magnetic energy as an electric motor using a rare earth magnet.

In the present invention, the stator core part of the vertical shaft type motor can optimize the core shape to minimize the iron loss generated in the motor by applying SMC (Soft Magnetic Composites) instead of a general electrical steel sheet.

In addition, in the present invention, a “round (R)” is formed in the shape of the core (teeth) by manufacturing the teeth of the stator core by the compression molding method using SMC powder, and the Back EMF (Electromotive Force) waveform is converted into a sine curve shape. It is possible to improve the generation of noise and vibration by making

The present invention relates to an axial gap type electric motor employing a non-rare earth magnet, and in particular, it can be applied to a vertical axis type permanent magnet synchronous motor. It can be applied to a water pump (EWP) for a cooling device that circulates cooling water such as a stack, a compressor, an oil pump, and the like.

10: pump housing 11: pump cover
11a: inlet 11b: outlet
11c: extension 12: body case
12a: groove 12b: bulkhead
12c: support shaft receiving portion 12d: fixed portion
13: upper cover 13a: connector housing
14: lower space 20: impeller
21: upper plate 22: lower plate
23: wing 30: rotor
31: back yoke 32: magnet
40: stator 41,411: teeth
41a, 411a; Shoe 41b: coil winding part
42,421,422: back yoke 42a: through hole
42b: assembly hole 42c: projection
43: bobbin 43a, 43b: flange
44: coil 45-45d: stator core
50: driver 51: PCB
52: projection 53: fixing bolt
54: electronic component 60: support shaft
61: sleeve bearing 62: bearing housing
63,64: O-ring 100: electric motor
200: water pump 55: pin

Claims (17)

An axial gap type electric motor for a water pump (EWP), comprising:
a rotor rotatably supported in a fluid flow passage between the pump cover and the body case;
a stator disposed in a lower space formed by the body case and the upper cover to generate a rotating magnetic field to rotate and drive the rotor; and
and a partition wall disposed on the body case and integrally formed with the body case and made of a thin plate to separate the rotor and the stator.
The rotor is annularly arranged and includes a plurality of magnets made of ferrite magnets; and a back yoke installed on the rear surface of the magnet to form a magnetic circuit, wherein the rotor is integrally formed under the impeller, a portion of the partition wall extends into the lower space, and a portion extends into the fluid flow passage. It is rotatably supported on the support shaft supported at one end of the support shaft receiving part,
In the stator, a plurality of teeth are arranged in an annular shape parallel to the axial direction on the same circumference to face the magnet of the rotor, and the plurality of teeth are connected to the back yoke at right angles to form a magnetic circuit. wherein the teeth are made of Soft Magnetic Composites (SMC), and the back yoke is formed by stacking a plurality of electrical steel plates. delete delete According to claim 1,
a sleeve bearing coupled to the outer periphery of the support shaft to rotatably support the rotor; and
The axial gap type electric motor further comprising a; bearing housing integrally formed with the lower plate of the impeller to accommodate the sleeve bearing therein. According to claim 1,
The stator is
a stator core having a plurality of teeth and a back yoke interconnected with the plurality of teeth to form a magnetic circuit;
a plurality of bobbins made of an insulating material integrally formed so as to surround an outer circumferential surface around which coils of each of the plurality of teeth are to be wound; and
a coil wound around the outer circumferential surface of the bobbin;
Each of the plurality of teeth is made in a "T" shape and is made of soft magnetic powder (SMC: Soft Magnetic Composites),
The back yoke is an axial gap type electric motor formed by stacking a plurality of electrical steel plates. 6. The method of claim 5,
Each of the plurality of teeth
a coil winding unit on which the coil is wound; and
and a shoe having a flange extending from the coil winding part;
The edge between the side and the tip of the shoe and the tip of the shoe are “rounded (R)” for an axial gap type electric motor. 7. The method of claim 6,
The coil winding part is formed of a triangular pole, and the shoe is an axial gap type electric motor having a trapezoidal cross-section. delete delete delete a pump cover having an inlet through which the fluid is introduced and an outlet through which the introduced fluid is discharged on one side and the other side, and the lower end open so that the impeller can be disposed in the fluid flow passage is extended to secure a wider space than the inlet;
a body case coupled to the pump cover to form a fluid flow passage inside the pump cover, the flange extending to form a recessed structure in the upper part corresponding to the open lower end of the pump cover, and having a lower space;
an upper cover coupled to the lower end of the body case to set the lower space to a sealing state;
a rotor rotatably supported in the fluid flow passage;
an impeller integrally formed with the rotor on the upper side of the rotor;
a stator disposed in the lower space to generate a rotating magnetic field to rotate and drive the rotor; and
and a partition wall disposed on the body case and integrally formed with the body case to separate the rotor and the stator.
The water pump in which the rotor and the stator form the axial gap type electric motor according to claim 1 . a pump housing having a lower space in a sealed state on one side, and an inlet through which a fluid is introduced and an outlet through which the introduced fluid is discharged are connected through a fluid flow passage;
a rotor rotatably supported in the fluid flow passage;
an impeller integrally formed with the rotor on the upper side of the rotor;
a stator disposed in the lower space to generate a rotating magnetic field to rotate and drive the rotor;
a partition wall disposed inside the pump housing and integrally formed with the body case to separate the rotor and the stator; and
and a support shaft rotatably supporting the rotor whose one end is supported by the partition wall;
The water pump in which the rotor and the stator form the axial gap type electric motor according to claim 1 . delete 13. The method of claim 11 or 12,
Each of the plurality of teeth has a flange extending from the coil winding portion of the shoe facing the rotor,
The edge between the side and the tip of the shoe is “rounded (R)” for the water pump. delete delete 13. The method of claim 12,
a bearing coupled to the outer periphery of the support shaft to rotatably support the rotor; and
The water pump further comprising a; bearing housing integrally formed with the lower plate of the impeller to accommodate the bearing therein.

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