JP5660942B2 - Electric pump and rotor for electric pump - Google Patents

Description

  The present invention relates to an electric pump provided with an axial gap type motor, and an electric pump rotor used therefor.

  In general, an electric pump includes a pump chamber (swirl chamber) that houses an impeller and a motor that rotationally drives the impeller, and by rotating the impeller, centrifugal force is applied to the liquid sucked into the pump chamber, and the pump chamber For example, it is used for cooling an engine mounted on a vehicle.

  As a motor used for an electric pump, in addition to a radial gap type motor in which the rotor and the stator are arranged opposite to each other in the radial direction of the rotating shaft, the rotor and the stator are arranged to face each other in the axial direction of the rotating shaft. There is an axial gap type motor.

  The axial gap type motor can be shortened in the axial direction as compared with the radial gap type motor, and thus is suitable for downsizing. In addition, in the axial gap type motor, by arranging a pair of rotors in the axial direction with respect to the stator, the magnetic flux loop formed in the axial direction of the stator can be used effectively. A small and efficient motor can be realized.

  Patent Document 1 describes an electric pump provided with an axial gap type motor. In the electric pump described in Patent Document 1, a rotor is rotatably supported on a shaft via a bearing, and an impeller is integrally formed on a rotating shaft of the rotor. Thereby, since there is no gap between the rotor and the impeller in the axial direction, it is possible to eliminate the fluid stirring resistance in the gap. Further, the rotor yoke and the rotor magnet can be easily fixed by covering the rotor with the resin constituting the impeller.

  An electric pump including an axial gap type motor in which a rotor and an impeller are integrated by covering the rotor with a resin constituting the impeller is also described in, for example, Patent Documents 2 and 3.

JP 2006-299975 A JP 2010-11581 A JP 2008-99456 A

  However, in the electric pumps described in Patent Documents 1 to 3, since the surface of the rotor facing the stator is covered with resin, the distance between the rotor magnet and the stator core is increased by the thickness of the resin. As a result, there is a problem that the performance of the motor cannot be exhibited sufficiently. Further, if the gap between the rotor and the stator is narrowed in order to improve the performance of the motor, the stirring resistance of the fluid flowing in the gap is increased, which in turn leads to a reduction in pump performance.

  The present invention has been made in view of this point, and a main object of the present invention is to provide an electric pump including an axial gap motor that can improve the performance of the motor and can be reduced in size.

  In order to solve the above-described problems, the present invention provides a plurality of rotor magnets on one surface of a rotor yoke, a communication hole is formed in the rotor yoke, and an impeller is integrated with the other surface of the rotor yoke by insert molding. In addition to molding, the resin constituting the impeller is filled between adjacent rotor magnets through communication holes.

  The rotor integrally molded with the impeller in this way can reduce the distance between the rotor magnet and the stator core because the surface of the rotor magnet facing the stator is not covered with resin. Thereby, the performance of the motor can be improved and the electric pump can be miniaturized. Further, by filling the space between the rotor magnets with resin, the surface of the rotor facing the stator can be flattened. Thereby, the stirring resistance of the fluid in the clearance gap between a rotor and a stator can be reduced. Further, since the impeller is integrally formed with the rotor yoke, it is not necessary to fix the rotor to the shaft with a bolt of the impeller by press-fitting and fixing the rotor to the shaft. Thereby, the surface shape of the center part of the impeller 20 can be optimally designed to be streamlined so that the stirring resistance is reduced hydrodynamically.

  That is, an electric pump according to the present invention includes a rotor that rotates about a rotation axis together with a shaft, a stator that is disposed opposite to the rotor in the axial direction of the rotation axis, and a side opposite to the surface of the rotor that faces the stator. An impeller fixed to the surface of the motor and a housing provided with a pump chamber for accommodating the impeller and forming a fluid flow around the rotation shaft, and the rotor is formed in a substantially circular plate shape fixed to the shaft. The rotor yoke has a plurality of rotor magnets distributed in the circumferential direction on a surface facing the stator of the rotor yoke, and the rotor yoke is integrally formed with the impeller by insert molding to constitute the impeller The resin is connected to the resin filled between adjacent rotor magnets through at least one communication hole formed in the rotor yoke. And wherein the Rukoto.

  ADVANTAGE OF THE INVENTION According to this invention, the electric pump provided with the axial gap type motor which was small and improved the motor efficiency and the pump efficiency can be provided.

It is sectional drawing which showed the structure of the electric pump in one Embodiment of this invention. It is the figure which showed the structure of the rotor integrally molded with the impeller, (a) is sectional drawing, (b) is a top view, (c) is sectional drawing along AA of (b). FIG. 2 is a partial cross-sectional view showing a positional relationship between a rotor and a stator in an axial gap motor, where (a) is a diagram showing a positional relationship in the present invention, and (b) is a diagram showing a conventional positional relationship. . It is the fragmentary sectional view which showed the structure of the impeller. It is the top view which showed the other structure of the rotor integrally molded with the impeller. It is sectional drawing which showed the structure of the rotor integrally molded with the impeller in the modification of this invention. It is sectional drawing which showed an example of the aspect of the rotating mechanism of the rotor integrally molded with the impeller. It is sectional drawing which showed the other example of the aspect of the rotating mechanism of the rotor integrally molded with the impeller.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the present embodiment, the direction parallel to the rotation axis is referred to as “axial direction”, and the radial direction around the rotation axis is referred to as “radial direction”. The present invention is not limited to the following embodiment. Moreover, it can change suitably in the range which does not deviate from the range which has the effect of this invention. Furthermore, combinations with other embodiments are possible.

  FIG. 1 is a cross-sectional view schematically showing the configuration of an electric pump according to an embodiment of the present invention.

  As shown in FIG. 1, a rotor 10 that rotates about a rotation axis J is fixed to a shaft 30, and a stator 40 is disposed in the axial direction of the rotation axis J so as to face the rotor 10. The motor is configured. The impeller 20 is fixed to the surface of the rotor 10 opposite to the surface facing the stator 40, and the impeller 20 is accommodated in the first housing 50.

  Pump chambers 70 and 71 that form a fluid flow around the rotation axis J are provided in the first housing 50, and the liquid sucked into the pump chamber 70 by the rotation of the impeller 20 causes centrifugal force. As a result, it is pushed out into the pump chamber 71 on the radially outer side, and finally discharged from an outlet (not shown) provided in the first housing 50.

  As shown in FIG. 1, the rotor 10 and the impeller 20 are integrally formed by insert molding.

  2A and 2B are diagrams schematically showing a configuration of the rotor 10 integrally formed with the impeller 20, FIG. 2A is a cross-sectional view, and FIG. 2B is a plan view seen from the stator 40 side. 2 (c) is a cross-sectional view along AA in FIG. 2 (b).

  As shown in FIGS. 2A to 2C, the rotor 10 is divided in a circumferential direction into a substantially circular plate-like rotor yoke 11 fixed to the shaft 30 and a surface of the rotor yoke 11 facing the stator 40. And a plurality of rotor magnets 12 arranged.

  Here, the rotor magnet 12 is arranged so that the magnetic poles in the axial direction (S pole and N pole) are alternately different, and the rotor yoke 11 is press-fitted into the shaft 30 with the through hole 14 formed in the center thereof. By doing so, it is fixed to the shaft 30.

  The rotor yoke 11 is integrally formed with the impeller 20 by insert molding, and the resin constituting the impeller 20 is interposed between adjacent rotor magnets 12 via at least one communication hole 13 formed in the rotor yoke 11. It is connected to the filled resin 23. Thereby, the surface of the rotor 10 facing the stator 40 is flattened by the resin 23 filled between the plurality of rotor magnets 12.

  That is, according to the present invention, the plurality of rotor magnets 12 disposed on the surface of the rotor yoke 11 facing the stator 40 need to be provided with a constant interval in order to suppress a magnetic short circuit between the adjacent rotor magnets 12. In particular, if the resin constituting the impeller 20 can be injected between the adjacent rotor magnets 12 during insert molding, the rotor magnet 12 is fixed to the rotor yoke 11 by the resin filled between the rotor magnets 12. The present invention has been conceived by thinking that it is possible.

  In order to fill the resin between the rotor magnets 12, a communication hole 13 penetrating in the axial direction is formed in a portion of the rotor yoke 11 where the rotor magnet 12 is not disposed (a portion where no magnetic flux loop is formed). It is necessary to keep it. If such a communication hole 13 is provided, a part of the resin injected to form the impeller 20 on one surface of the rotor yoke 11 at the time of insert molding is formed in the rotor yoke 11 via the communication hole 13. It flows into the other surface and is also injected between the rotor magnets 12. As a result, the resin constituting the impeller 20 formed on one surface of the rotor yoke 11 is connected to the resin 23 filled between the rotor magnets 12 disposed on the other surface of the rotor yoke 11, so that the rotor magnet 12 can be fixed to the rotor yoke 11. In addition, by filling the space between the rotor magnets 12 with the resin 23, the surface of the rotor 10 facing the stator 40 can be flattened.

  FIG. 3 is a partial sectional view showing the positional relationship between the rotor and the stator in the axial gap type motor, and FIG. 3A is a diagram showing the positional relationship between the rotor 10 and the stator 40 in the present invention. FIG. 3B is a diagram illustrating a positional relationship between the conventional rotor 110 and the stator 140. The stator 40 has a canned structure in which a stator core 40a and a stator coil (not shown) wound around the stator core 40a are covered with a mold resin 40b.

  As shown in FIG. 3 (a), the rotor 10 integrally formed with the impeller 20 in the present invention is not covered with resin on the surface of the rotor magnet 12 facing the stator 40. Therefore, the rotor magnet 12 and the stator core 40a The distance D1 can be shortened. On the other hand, as shown in FIG. 3B, the rotor 110 integrally formed with the conventional impeller 120 is covered with a resin 122 on the surface facing the stator 140 of the rotor magnet 112. The distance D2 between 112 and the stator core 140a is longer than the distance D1 by the thickness of the resin 122. Therefore, by making the rotor 10 and the impeller 20 integrally formed as in the present invention, the distance D1 between the rotor magnet 12 and the stator core 40a can be shortened, so that the performance of the motor is improved. Can do.

  Further, as shown in FIG. 3A, in the rotor 10 integrally formed with the impeller 20 in the present invention, the resin 22 is filled between the rotor magnets 12, so that the rotor 10 on the side facing the stator 40 is disposed. The surface can be flattened. Thereby, the stirring resistance of the fluid in the clearance gap between the rotor 10 and the stator 40 can be reduced.

  Here, as shown in FIG. 2C, the side surface of the rotor magnet 12 preferably has an inclined portion 12 a where the distance between the adjacent rotor magnets 12 is increased on the side facing the stator 40. . Thereby, it becomes easy to make the surface of the resin 23 filled between the rotor magnets 12 flush with the surface of the rotor magnet 12, and the surface of the rotor 10 facing the stator 40 can be easily flattened.

  2 (a) and 2 (b), the rotor yoke 11 has a boss portion 15 having a through hole 14 at the center thereof, and the communication hole 13 extends along the outer periphery of the boss portion 15. It is preferable that a plurality are formed in the circumferential direction. Thereby, the flow of the resin injected between the rotor magnets 12 through the communication holes 13 can be performed more smoothly. As a result, the resin 23 can be uniformly filled between the rotor magnets 12.

  Further, the rotor yoke 11 can be fixed to the shaft 30 by press-fitting the through hole 14 of the boss portion 15 into the shaft 30. Since the impeller 20 is integrally formed with the rotor yoke 11, it is not necessary to fix the impeller 20 itself to the shaft 30. As a result, in order to fix the impeller 20 to the shaft 30, it is not necessary to insert a metal bush at the center portion of the impeller 20 and fasten it to the shaft 30 with bolts. It is possible to optimally design a streamline that mechanically reduces the stirring resistance.

  Further, since the communication hole 13 is formed outside the magnetic flux loop in which the rotor magnet 12 is not disposed, the communication hole 13 does not affect the magnetic flux loop and does not cause a reduction in performance of the motor.

  Further, the shape, number, position, and the like of the communication hole 13 formed in the rotor yoke 11 are not particularly limited, and can be appropriately determined according to the required performance of the motor.

  In addition, the structure of the rotor 10 integrally molded with the impeller 20 in the present invention can be formed using a normal insert molding method. Specifically, a plurality of rotor yokes 11 are temporarily fixed to one surface of the rotor yoke 11 in which the communication holes 13 are formed with an adhesive or the like, and the rotor yoke 11 is disposed in a mold, and the inside of the cavity that forms the impeller 20 is formed. Pour molten resin into At that time, a part of the injected resin passes through the communication hole 13 and is filled also between the rotor magnets 12 on the opposite surface of the rotor yoke 11. Thereby, the rotor 10 integrally formed with the impeller 20 having the configuration shown in FIGS. 2A to 2C can be formed.

  As described above, the electric motor according to the present invention is characterized by the configuration of the rotor 10 formed integrally with the impeller 20, and the specific configuration of the electric motor will be described again with reference to FIG. The configuration other than the rotor 10 integrally formed with the impeller 20 is not limited to the configuration shown in FIG. 1 and can be changed as appropriate without departing from the scope of the effects of the present invention.

  As shown in FIG. 1, the rotor 10, the impeller 20, and the stator 40 are accommodated in a first housing 50 and a second housing 51, and the first housing 50 and the second housing 51 are interposed via an O-ring. They are fastened together with bolts.

  The rotor 10 is fixed to the shaft 30, and the impeller 20 formed integrally with the rotor 10 rotates about the rotation axis J together with the rotor 10.

  As shown in FIG. 2A, the impeller 20 includes an impeller body 24 provided with a plurality of blades and a shroud 25 that connects upper ends of the plurality of blades. Here, the impeller body 24 and the shroud 25 are formed by, for example, forming the impeller body 24 and the shroud 25 by primary injection using separate molds, respectively, and then, as shown in the partial cross-sectional view of FIG. The shroud 25 can be fitted to each other, and the respective peripheral portions can be formed by being fused to each other with the resin 27 injected by secondary injection.

  The stator 40 is disposed opposite the rotor 10 in the axial direction of the rotation axis J. The stator 40 has a canned structure covered with mold resin, and is integrated with the second housing 51. Thereby, the shaft 30 is rotatably supported by the stator 40 via the bearing 41.

  In addition, the second rotor 10 is disposed on the opposite side of the rotor 10 integrated with the impeller 20 in the axial direction of the rotation axis J so as to face the stator 40.

  A circuit board 60 covered with a mold resin is mounted on the bottom of the second housing 51. On the circuit board 60, a switching element for driving and controlling the motor is mounted.

  In addition, in the first housing 50 and the second housing 51, a motor, a circuit board, and the like are provided separately from the flow path through which the liquid sucked into the pump chambers 70 and 71 is discharged from the outlet by the rotation of the impeller 20. A plurality of flow paths are formed for cooling.

  For example, a flow path along the radial direction is formed in the gap between the rotor 10 and the stator 40, and this flow path is a through-hole formed in the impeller 20 as shown in FIG. 26 is in communication with the pump chamber 70. Thereby, a liquid circulates in the clearance gap between the rotor 10 and the stator 40, and the upper surface of the stator 40 can be cooled.

  In addition, a flow path 72 along the axial direction is formed in the gap between the stator 40 and the inner wall of the second housing 51, whereby the side surface of the stator 40 can be cooled. Further, a flow path 73 along the radial direction is formed in the gap between the rotor 10 and the bottom wall of the second housing 51, whereby heat from the circuit board 60 is transferred to the bottom wall of the second housing 51. It can be transmitted to the flow path 73 via

  If a through hole (not shown) is also formed in the central portion of the shaft 30, the flow paths 72 and 73 can be communicated with the pump chamber 70 through the through hole, thereby allowing the liquid to flow. It can be circulated.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, in the above embodiment, the communication hole 13 of the rotor yoke 11 is formed along the outer periphery of the boss portion 15. For example, as shown in the plan view of FIG. In such a case, the communication hole 13 may be formed between the adjacent rotor magnets 12.

  Moreover, in the said embodiment, although the surface facing the stator 40 of the rotor 10 was planarized with the resin with which it filled between the rotor magnets 12, the resin inject | poured into the rotor magnet 12 side through the communicating hole 13 is used. Even if it is formed so as to cover the rotor magnet 12, the effect of the present invention can be exhibited if the resin formed on the rotor magnet 12 is thinned. In this case, it is particularly effective when the rotor magnet 12 is made of a material having low corrosion resistance.

  In the above-described embodiment, the pair of rotors 10 and 10 are disposed in the axial direction so as to face the stator 40, but only the rotor 10 integrally formed with the impeller 20 may be used.

(Modification of this embodiment)
(Modification 1)
In the above embodiment, the rotor 10 is fixed to the shaft 30 and the shaft 30 is rotatably supported by the stator 40 via the bearing 41. However, the shaft 30 is fixed by the stator 40 and the rotor 10 is supported by the bearing. The shaft 30 may be rotatably supported.

  FIG. 6 is a cross-sectional view showing a configuration of a rotor integrally formed with the impeller of the electric pump in this modification.

  As shown in FIG. 6, the rotor 10 is supported via a bearing 41 so that the shaft 30 can rotate. Further, the shaft 30 is fixed to the stator 40.

  Also in this modification, the basic configuration of the rotor 10 integrally formed with the impeller 20 can be applied to the configuration described in the above embodiment as it is, but a part of the rotor yoke 11 contacts the outer peripheral surface of the bearing 41. You may provide the boss | hub part 11a. Thereby, since the boss part 11a of the rotor 10 is contacted over the entire axial direction of the bearing 41, the rotor 10 can be stably supported on the shaft 30. Note that the boss portion 11 a may be formed of a member different from the rotor yoke 11.

(Modification 2)
The present invention relates to a rotor yoke integrally formed with an impeller 20 in an electric pump having an axial gap type motor in which a rotor 10 and a stator 40 are arranged to face each other in the axial direction of a rotation axis J. 11 is integrally formed with the impeller 20 by insert molding, and the resin constituting the impeller 20 is filled between the adjacent rotor magnets 12 through at least one communication hole 13 formed in the rotor yoke 11. It is characterized in that it is configured to be connected to.

  Therefore, the rotation mechanism of the rotor 10 integrally formed with the impeller 20 having such a configuration can employ various modes.

  Hereinafter, an example of the aspect of the rotation mechanism of the rotor 10 integrally formed with the impeller 20 will be described with reference to FIGS.

  In the example shown in FIG. 7, the rotor 10 integrally formed with the impeller 20 is provided at the center of the stator 40 and at the center of the housing 50 on the upper and lower sides of the rotation axis J in the axial direction. The protrusion 50a is rotatably supported. Therefore, in this example, the shaft 30 and the bearing 41 are not provided.

  The stator 40 has a canned structure in which a stator coil is wound around a stator core and covered with a mold resin, and the protrusion 40c can be formed at the time of molding the mold resin.

  Further, the protrusion 50 a provided at the center of the housing 50 is supported by the housing 50 via a plurality of ribs 50 b extending radially inward from the inner peripheral wall of the housing 50. Since the upper portion of the impeller 20 in the axial direction serves as a suction port of the pump chamber, it is preferable that the plurality of ribs 50b that support the protrusions 50a be arranged so that the flow path resistance is as small as possible.

  In the example shown in FIG. 8, the rotor 10 formed integrally with the impeller 20 is rotatably supported by a bearing 41 supported by the housing 50 on the outer side in the radial direction of the rotating shaft J. In this example, the second rotor 10 is disposed on the opposite side of the rotor 10 integrally formed with the impeller 20 so as to face the stator 40, and the second rotor 10 is also in the radial direction of the rotation axis J. The outer side is rotatably supported by a bearing 41 supported by the housing 50.

  Here, the pair of rotors 10 arranged vertically with respect to the stator 40 are connected to each other by a connecting portion 11b extending in the axial direction along the rotation axis J at the center of each rotor yoke 11. Yes. In addition, you may comprise this connection part 11b with a member different from the rotor yoke 11. FIG.

  The electric pump of the present invention is useful for, for example, a water pump for cooling an engine.

10 Rotor
11 Rotor yoke
11a Boss
11b connecting part
12 Rotor magnet
12 Rotor yoke
12a Inclined part
13 Communication hole
14 Through hole
15 Boss
20 impeller
22, 23, 27 Resin
24 Impeller body
25 Shroud
26 Through hole
30 shaft
40 stator
40a Stator core
40b Mold resin
40c protrusion
41 Bearing
50 First housing
50a Protrusion
50b rib
51 Second housing
60 circuit board
70, 71 Pump room
72, 73 channels

Claims (10)

A rotor that rotates about a rotation axis together with a shaft;
A stator disposed in the axial direction of the rotating shaft so as to face the rotor;
An impeller fixed to a surface of the rotor opposite to the surface facing the stator;
A housing that houses the impeller and is provided with a pump chamber that forms a fluid flow around a rotation axis;
An electric pump comprising:
The rotor is
A substantially circular plate-like rotor yoke fixed to the shaft;
A plurality of rotor magnets arranged in a circumferential direction on a surface of the rotor yoke facing the stator; and
Have
The rotor yoke is integrally formed with the impeller by insert molding,
The electric pump in which the resin constituting the impeller is connected to the resin filled between the adjacent rotor magnets through at least one or more communication holes formed in the rotor yoke.   The electric pump according to claim 1, wherein a surface of the rotor facing the stator is flattened by a resin filled between the rotor magnets.   2. The electric pump according to claim 1, wherein a side surface of the rotor magnet has an inclined portion that increases a distance between adjacent rotor magnets on a side facing the stator.   The electric pump according to claim 1, wherein the rotor yoke is fixed to the shaft by press-fitting a through hole formed in a central portion thereof into the shaft.   The electric pump according to claim 1, wherein a central portion of the impeller has a streamlined surface shape. The rotor yoke has a boss portion having a through hole at the center thereof,
The electric pump according to claim 1, wherein a plurality of the communication holes are formed in a circumferential direction along an outer periphery of the boss portion.   2. The electric pump according to claim 1, wherein a second rotor is disposed opposite to the rotor in the axial direction of the rotation shaft on the opposite side of the rotor. The impeller has an impeller body provided with a plurality of blades, and a shroud connecting upper ends of the plurality of blades,
2. The electric pump according to claim 1, wherein the impeller body and the shroud are fused to each other at a peripheral portion with a resin injected by secondary injection. A rotor rotatably supported by a shaft via a bearing;
A stator disposed in the axial direction of the rotating shaft so as to face the rotor;
An impeller fixed to a surface of the rotor opposite to the surface facing the stator;
A housing that houses the impeller and is provided with a pump chamber that forms a fluid flow around a rotation axis;
An electric pump comprising:
The shaft is fixed to the stator;
The rotor is
A substantially circular plate-shaped rotor yoke;
A plurality of rotor magnets arranged in a circumferential direction on a surface of the rotor yoke facing the stator; and
Have
The rotor yoke is integrally formed with the impeller by insert molding,
The electric pump in which the resin constituting the impeller is connected to the resin filled between the adjacent rotor magnets through at least one or more communication holes formed in the rotor yoke. The rotor and the stator is an electric pump rotor example Bei the axial gap motor which is disposed opposite to the axial direction of the rotary shaft,
The rotor is
A substantially circular plate-shaped rotor yoke;
A plurality of rotor magnets arranged in a circumferential direction on a surface of the rotor yoke facing the stator; and
Have
The rotor yoke, by insert molding, are integrally molded with Lee Npera,
The electric pump rotor, wherein the resin constituting the impeller is connected to the resin filled between the adjacent rotor magnets through at least one communication hole formed in the rotor yoke.

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