JP2015063899A - Electric water pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric water pump capable of ensuring sealability between a stator and a pump section.SOLUTION: An electric water pump includes: a transverse wall extending radially outward from an impeller-side opening of a cylindrical portion of a can in a direction of a rotary shaft of a rotor; and a longitudinal wall extending outward in the direction of the rotary shaft of the rotor from a radially end portion of the transverse wall, the transverse wall being held between the motor housing and a stator so as to seal the motor housing from the transverse wall and to seal the cylindrical portion from the stator.

Description

  The present invention relates to an electric water pump.

  As this type of technique, a technique described in Patent Document 1 below is disclosed. Patent Document 1 discloses a structure in which the flange portion of the can is sandwiched between the motor housing and the pump housing so that the fluid flowing into the pump portion does not flow into the stator side.

JP 2012-021464

In the technique described in Patent Document 1, sealing is performed by sandwiching the can flange portion between the pump housing and the motor housing in the axial direction. In this case, it is necessary to make the flange portion large in the radial direction and to sandwich the end portion between the pump housing and the motor housing. However, when the can is formed by press working, it is difficult to form the flange portion with high planar accuracy, and there is a possibility that the sealing performance between the stator and the pump portion cannot be ensured.
The present invention has been focused on the above problems, and an object of the present invention is to provide an electric water pump that can ensure a sealing property between a stator and a pump portion.

  In order to achieve the above object, in the electric water pump according to the present invention, the rotor of the cylindrical portion of the can extends from the opening on the impeller side in the rotation axis direction of the rotor to the outside in the radial direction and from the radial end of the lateral wall portion. A vertical wall portion extending outward in the rotation axis direction of the motor, and sealing between the motor housing and the vertical wall portion, sealing between the cylindrical portion and the stator, and a horizontal wall between the motor housing and the stator. The part was sandwiched.

  Therefore, in this invention, the sealing performance between a stator and a pump part is securable.

1 is a cross-sectional view of an electric water pump of Example 1. FIG.

Example 1
The electric water pump 1 of the first embodiment is a cooling pump that uses a cooling medium (cooling water) as a working fluid and is incorporated in a circulation circuit connected to a heat exchanger (radiator). Engine), a driving motor, an inverter, and the like. The electric water pump 1 includes a pump unit 2, a motor unit 3 as a drive unit that drives the pump unit 2, and a control unit 4 that controls the operation of the motor unit 3. The pump unit 2, the motor unit 3, and the control unit 4 are accommodated in a housing 5.
[Pump part]
The pump unit 2 is constituted by an impeller 20 accommodated in a pump chamber 51c formed by a pump housing 51 and a motor housing 52. The pump housing 51 has a suction port 51a that extends on the rotating shaft of the impeller 20 and opens into the pump chamber 51c. A discharge passage 51b is provided on the outer peripheral side of the impeller 20 by the pump housing 51 and the motor housing 52.
The electric water pump 1 is a centrifugal pump that applies pressure to the cooling water in the radial direction as the impeller 20 rotates. As the impeller 20 rotates, the cooling water is sucked into the pump chamber 51c from the suction port 51a and discharged to the outside through the discharge passage 51b. The impeller 20 is an impeller having a plurality of blades 20a, and is formed coaxially with a rotor 31 described later. The blades 20a are arranged radially about the rotation axis of the impeller 20.

[Motor part]
The motor unit 3 is an inner rotor type DC brushless motor, and includes a stator 30 arranged in a cylindrical shape and a rotor 31 provided on the inner peripheral side of the stator 30. The stator 30 and the rotor 31 are accommodated in a motor chamber 52a in the motor housing 52.
The stator 30 has a plurality of coils 30a, and generates a magnetic flux on the inner peripheral side when the coil 30a is energized. The coils 30a are arranged in a cylindrical shape and are entirely molded with resin. One opening of the coils 30a arranged in a cylindrical shape is closed with resin, and forms a bottom 30b. The appearance of the stator 30 is formed in a cup shape as a whole, and a stepped portion 30c formed in a convex shape along the inner peripheral surface 30d is posted on the bottom surface 30e.
The rotor 31 integrally includes a magnetic pole holding portion 31a and a shaft portion 31b, and is formed integrally with the impeller 20 by, for example, injection molding of resin. The impeller 20 may be a member separate from the rotor 31 and fixed to the rotor 31. The magnetic pole holding portion 31a is a columnar member that is installed so as to face the inner peripheral surface of the stator 30 (coil 30a) with a slight gap (air gap) therebetween. A plurality of permanent magnets 31c (permanent magnets in which N poles and S poles are alternately arranged in the circumferential direction) are held corresponding to the coils 30a. The shaft portion 31b is a shaft member that transmits power for rotating the impeller 20. An axial through hole 31d penetrating in the axial direction is formed in the axial center portion of the shaft portion 31b and the magnetic pole holding portion 31a, and the support shaft 32 is inserted into the axial through hole 31d. The support shaft 32 is fixed by the bottom 30b of the stator 30 and the pump housing 51.

  A motor housing 52 is provided on the outer periphery of the stator 30. The motor housing 52 is molded of resin and has a small-diameter cylindrical portion 52e that forms the motor chamber 52a and a large-diameter cylindrical portion 52f that forms the pump chamber 51c together with the pump housing 51. A partition wall portion 52g is formed between the small-diameter cylindrical portion 52e and the large-diameter cylindrical portion 52f so as to protrude to the inner peripheral side over the entire circumference. The partition wall portion 52g is located on the opening side of the stator 30. A protruding portion 52h that protrudes toward the small diameter cylindrical portion 52e is formed at the inner peripheral side end of the partition wall portion 52g. The protruding part 52h is composed of a large diameter part 52i on the partition wall part 52g side and a small diameter part 52j connected to the large diameter part 52i. The outer diameter of the large diameter part 52i is formed larger than the outer diameter of the small diameter part 52j. A seal groove 52k is formed on the entire surface of the small diameter cylindrical portion 52e facing the pump housing 51, and an annular seal member 57 is provided in the seal groove 52k. The seal member 57 seals between the bottom surface of the seal groove 52k and the opening side end surface of the pump housing 51.

  Between the stator 30 and the rotor 31, a can 54 formed in a cylindrical shape with a nonmagnetic metal material is inserted. The can 54 is formed by pressing, and the thickness of the cylindrical portion 54e is 0.5 [mm] or less. The motor chamber 52a is divided into a stator chamber 52c and a rotor chamber 52d by a cylindrical portion 54e of the can 54. The inner peripheral surface 30d of the stator 30 is provided in contact with the outer periphery of the cylindrical portion 54e. In the opening of the cylindrical portion 54e on the bottom 30b side of the stator 30, a lateral wall portion 54a extending to the inner peripheral side and a vertical wall portion 54b extending outward in the axial direction from the inner peripheral side end portion of the lateral wall portion 54a are formed. . An annular seal member 55 is provided on the outer peripheral side of the vertical wall portion 54b, and seals between the vertical wall portion 54b and the side surface of the step portion 30c of the stator 30. At the opening on the impeller 20 side of the cylindrical portion 54e, a horizontal wall portion 54c extending to the outer peripheral side and a vertical wall portion 54d extending outward in the axial direction from the outer peripheral side end portion of the horizontal wall portion 54c are formed. The inner peripheral surface of the vertical wall portion 54d is formed to have substantially the same diameter as the outer diameter of the large diameter portion 52i of the protruding portion 52h of the motor housing 52. An annular seal member 56 is provided on the inner peripheral side of the vertical wall portion 54d, and seals between the vertical wall portion 54d and the outer peripheral surface of the small diameter portion 52j of the protruding portion 52h.

[Control unit]
A control unit 4 is provided on the bottom 30b side of the stator 30. The control unit 4 includes a substrate 40 on which electronic elements are assembled, and the substrate 40 and the coil 30a of the stator 30 are connected. The control unit 4 is accommodated in the control unit housing 53.
[Action]
Since the rotor 31 is a permanent magnet 31c, the cooling water may enter the rotor chamber 52d, but since the stator 30 is the coil 30a, the rotor chamber 52d and the stator chamber 52c are prevented from entering the stator chamber 52c. It is necessary to seal between. Sealing between the pump housing 51 and the can 54 and between the motor housing 52 and the can 54 may be considered, but in this case, the pump housing 51 and the motor housing 52 are disposed in the opening of the can 54 on the impeller 20 side. It is necessary to form a flange portion extending to the joint portion. The flange portion is formed into a thin plate shape by pressing. However, if a flange portion having a large area is to be formed, a flat surface does not appear, and the sealing performance may be deteriorated.
Therefore, in the first embodiment, the lateral wall portion 54c spreading radially outward from the opening on the impeller 20 side in the rotational axis direction of the rotor 31 of the cylindrical portion 54e of the can 54, and the rotational shaft of the rotor from the radial end portion of the lateral wall portion 54c. A vertical wall portion 54d extending outward in the direction, sealed between the motor housing 52 and the vertical wall portion 54d, and sealed between the cylindrical portion 54e and the stator 30, and the motor housing 52 and the stator 30 The horizontal wall portion 54c is sandwiched between the two.
Thereby, since the sealing surface can be secured at a position close to the cylindrical portion 54e of the can 54, the flatness of the sealing surface can be easily ensured, and the sealing performance can be improved. Further, since the can 54 and the stator 30 can be simultaneously fixed by the motor housing 52, the assembling workability can be improved.
In the first embodiment, the partition wall portion 52g extending to the inner peripheral side is formed at a position outside the stator 30 of the motor housing 52 in the axial direction. Thereby, the partition between the stator chamber 52c and the pump chamber 51c can be formed by the motor housing 52. Therefore, since it is not necessary to form a flange portion having a large area on the can 54, the processing of the can 54 is facilitated.

[effect]
(1) An electric water pump 1 mounted on a vehicle, wherein the stator 30 is integrally covered with resin, the rotor 31 is given a rotational force by the magnetic flux generated by the stator 30, and the rotational axis direction of the rotor 31 An impeller 20 fixed to the end portion and a stator 30 are fixedly accommodated, and a motor housing 52 that rotatably supports and accommodates the rotor 31 and the impeller 20, and an inner peripheral side of the stator 30, A can 54 having a cylindrical portion 54e disposed between the rotor 31 and the stator 30 and formed of a nonmagnetic metal material. The can 54 is an impeller in the direction of the rotation axis of the rotor 31 of the cylindrical portion 54e. The motor housing 52 and the vertical wall portion 54d have a horizontal wall portion 54c extending radially outward from the opening on the 20 side, and a vertical wall portion 54d extending in the rotational axis direction of the rotor 31 from the radial end portion of the horizontal wall portion 54c. Between the cylindrical portion 54e and the stator 30. The transverse wall 54c is sandwiched between the motor housing 52 and the stator 30.
Therefore, since the sealing surface can be secured near the cylindrical portion 54e of the can 54, the flatness of the sealing surface can be easily ensured, and the sealing performance can be improved. Further, since the can 54 and the stator 30 can be simultaneously fixed by the motor housing 52, the assembling workability can be improved.

(2) A partition wall portion 52g extending toward the inner peripheral side is provided at a position on the outer side in the axial direction of the stator 30 of the motor housing 52.
Therefore, since it is not necessary to form a flange portion having a large area on the can 54, the processing of the can 54 is facilitated.
(3) The inner peripheral surface of the stator 30 and the cylindrical portion 54e of the can 54 are brought into contact with each other.
Therefore, the air gap between the stator 30 and the rotor 31 can be reduced.
(4) The wall thickness of the cylindrical portion 54e of the can 54 is set to 0.5 [mm] or less.
Therefore, the air gap between the stator 30 and the rotor 31 can be reduced.

[Other Examples]
As described above, the present invention has been described based on the first embodiment. However, the specific configuration of each invention is not limited to the first embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Are included in the present invention.

1 Electric water pump
20 Impeller
30 stator
31 rotor
52 Motor housing
52g Bulkhead
54 Can
54c Horizontal wall
54d vertical wall
54e Cylindrical part

Claims (4)

An electric water pump mounted on a vehicle,
A stator in which coils arranged in an annular shape are integrally covered with resin;
A rotor to which a rotational force is given by a magnetic flux generated by the stator;
An impeller fixed to an end of the rotor in the rotation axis direction;
A motor housing for fixing and accommodating the stator and for rotatably supporting the rotor and the impeller;
A can having an inner peripheral side of the stator and having a cylindrical portion disposed between the rotor and the stator and formed of a nonmagnetic metal material;
Have
The can includes a horizontal wall portion extending radially outward from an opening on the impeller side of the cylindrical portion in the rotational axis direction of the rotor, and a vertical wall extending in a rotational axis direction of the rotor from a radial end portion of the horizontal wall portion. And
Sealing is performed between the motor housing and the vertical wall portion, sealing is performed between the cylindrical portion and the stator, and the lateral wall portion is sandwiched between the motor housing and the stator. Electric water pump featuring In the electric water pump according to claim 1,
The electric water pump according to claim 1, wherein the motor housing has a partition wall portion extending inward on an axially outer side of the stator. In the electric water pump according to claim 1 or claim 2,
An electric water pump, wherein an inner peripheral surface of the stator is in contact with the cylindrical portion of the can. In the electric water pump according to any one of claims 1 to 3,
The electric water pump according to claim 1, wherein the cylindrical portion of the can has a thickness of 0.5 [mm] or less.

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