JP7221102B2 - electric water pump - Google Patents

Description

The present invention relates to an electric water pump. More particularly, the present invention relates to electric water pumps for pumping fluids such as vehicle coolant.

2. Description of the Related Art Conventionally, an electric water pump has an impeller disposed inside a pump casing having a suction port and a discharge port, and rotating integrally with a rotor to feed cooling water from the suction port to the discharge port. A water pump is known (see Patent Document 1, for example).

In the electric water pump of Patent Document 1, the support member located between the suction port of the pump casing and the spiral chamber is composed of a column, a ring, and three ribs 3 connecting them. The material is, for example, PPO resin. A key hole is formed in the cylinder. Between the three ribs, through holes are formed through which hot water or the like can pass.

The can is attached to the pump casing to cover the rotor. The can is attached by fitting the flange of the can to the inner surface of the pump casing. Thereby, the can is fixed to the pump casing in a direction perpendicular to the rotation axis. Also, one end of the shaft is fitted into the concave portion of the can. As a result, the shaft and rotor are rotatably supported with respect to the pump casing via the can and support member, and are positioned in a direction perpendicular to the rotation axis.

JP 2006-283682 A

By the way, since the shaft is configured to be positioned by the support member on the pump casing side and the concave portion of the can, the shaft may be attached at an angle due to manufacturing tolerances of the pump casing and the can. For this reason, it is difficult to assemble unless a sufficient clearance (also called an air gap) is provided between the rotor and the can in consideration of the case where the rotor is attached at an angle. However, when an air gap is provided, the magnetic resistance increases, resulting in output loss of the motor, and in some cases, self-excited whirling and uneven speed may occur in the rotating system. Therefore, there is room for improvement.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric water pump capable of reducing motor output loss and improving whirling and speed unevenness of a rotating system.

[1] The electric water pump according to the present invention is
a pump casing having an inlet, an outlet, and a volute;
a rotor having a rotor magnet and an impeller housed in the spiral chamber;
a stator disposed radially outward of the rotor;
a support shaft that is fixed to the pump casing and rotatably supports the rotor;
a resin-made partition flange fixed to the pump casing and a concave portion fitted to the support shaft; An electric water pump comprising a can attached to
The pump casing is formed by die casting of a conductive light metal material, and has a support shaft holding portion that has a socket length that extends over 40% or more of the total length of the support shaft and holds the support shaft. set in one body,
The can is positioned at the axial center of the support shaft by the recess, and the pump casing and the partition flange are engaged with each other via a first play that absorbs positional deviation in the circumferential and radial directions .

According to this configuration, the pump casing is formed by die-casting of a conductive light metal material, and has a socket length covering 40% or more of the total length of the support shaft. A holding portion is integrally provided. As a whole, the support shaft press-fitted into the support shaft holding portion of the pump casing is used as a reference, and the concave portion of the can is fitted to the support shaft. Therefore, the pump casing, the rotor with the impeller, the can, and the stator are aligned using the support shaft as a positioning reference.

At this time, since the can is positioned (centered) by the concave portion of the can with respect to the support shaft that is firmly press-fitted and fixed to the pump casing, the so-called "play" that absorbs misalignment between the compartment flange portion and the pump casing. If you don't have ", you will not be able to assemble it. In this regard, since the pump casing and the partition flange portion are engaged with the first play in the circumferential and radial directions, a relatively large air gap, which takes into consideration the case where the support shaft is attached at an angle, as in the prior art, is eliminated. not required and requires a minimal air gap. As a result, it is possible to reduce the output loss of the motor due to the conventional air gap, and to improve whirling and speed unevenness that may occur in the rotating system.

[2] Further, in the electric water pump of the present invention,
The stator has a plurality of yoke covering portions and a plurality of tooth covering portions on each of the inward tooth portions of an iron core laminated with a magnetic material and having a plurality of yoke portions connected to each other, and is divided into two pieces in the lamination direction. A pair of insulating bobbins are attached, an electromagnetic coil is wound around the insulating bobbins, and an annular stator ring is fitted to the can to form an annular shape,
The stator is positioned at the axial center of the support shaft through the can by fitting the inner diameter surface of the inwardly-shaped tooth portion to the peripheral surface of the can,
The can and stator ring are engaged with a second play that accommodates circumferential and radial misalignment .

According to such a configuration, the can is positioned (centered) by the concave portion of the can with respect to the support shaft firmly press-fitted into the pump casing, and the stator is attached to the support shaft. At this time, the inner diameter surface of the tooth portion, which is the magnetic field portion of the stator, is fitted into the cylinder portion (separation wall portion) of the can. Assembly becomes difficult if there is no so-called "play" between it and the partition flange portion of the can to which it is attached. In this regard, in the present invention, the can and the stator ring are configured to engage with each other with a second play in the circumferential and radial directions. As a result, the support shaft, rotor, can, and stator are all aligned along the support shaft (axis center) in this order. It is possible to further improve whirling and speed unevenness that may occur.

[3] Further, in the electric water pump of the present invention,
A power supply coupler having a power supply terminal is provided on the partition flange portion of the can,
a control board for controlling the magnetic field of the stator is held on the end surface of the stator ring by a fixed leg provided so as to extend from the insulating bobbin, and is electrically connected to the power supply terminal;
The power supply terminal is provided with a stress absorbing portion capable of tilting so as to absorb the second play, and the insulating bobbin is provided with a tip end of the power supply terminal connected to the through hole of the control board adjacent to the fixed leg. It is preferable to provide a guiding portion for guiding.

According to such a configuration, the power supply coupler is provided on the non-magnetic and electrically insulating resin can. On the other hand, since the control board needs to be provided near the stator and on the side where the impeller does not exist, the power supply coupler is far from the control board, so the positional deviation of the power supply terminals with respect to the control board tends to increase. Furthermore, since a second play is provided between the can and the stator that fixes the control board, the feed terminal of the feed coupler needs to be able to absorb the second play as well. This is because if the relative positional relationship between the can and the control board changes due to the second play, it becomes difficult to insert the power supply terminal into the through-hole (hole for soldering) of the control board. In this respect, according to the present invention, the power supply terminal is provided with a tiltable stress absorbing portion and the insulating bobbin is provided with a guide portion (tapered terminal guide hole), so that the power supply terminal can be easily inserted into the substrate.

[4] Further, in the electric water pump of the present invention,
A board housing is provided that covers the control board with a conductive metal material,
The pump casing, the partition flange portion, and the substrate housing are arranged in this order and screwed together by a fastening member, and a conductive collar is provided between the fastening member and the partition flange portion to allow the first play. It is preferable to interpose a member.

According to such a configuration, the substrate housing functions as an electromagnetic shield (noise countermeasure member) that separates the electric device from the outside world (an electric water pump is mounted, for example, in the engine room of an automobile). Therefore, it must be connected to the battery ground. At this time, since the can interposed between the pump casing and the substrate housing is made of non-conductive resin, by interposing the conductive collar member in the screw insertion hole of the can, the substrate housing, the conductive It can be grounded via the collar member, pump casing, engine block, and battery.

1 is a cross-sectional view showing the structure of an electric water pump according to the present invention; FIG. 1 is an exploded perspective view of an electric water pump according to the present invention; FIG. (a) is a cross-sectional view of a support shaft and a recess according to the present invention. (b) is a cross-sectional view of a support shaft and a recess according to another aspect of the present invention; FIG. 4 is a cross-sectional view of a main part of a support shaft and a washer according to the present invention;

Embodiments of the present invention will be described below with reference to the drawings. The drawings conceptually (schematically) show the electric water pump 1 .

As shown in FIGS. 1 and 2, an electric water pump 1 according to one embodiment of the present invention is, for example, a so-called canned cooling water pump for automobiles, and includes a pump casing 10, a support shaft 20, and a rotor 30. , a stator 40 , a can 60 , a control board 70 and a board housing 80 .

The pump casing 10 includes a fluid suction port 11, a spiral chamber 12 for collecting the fluid that enters through the suction port 11 and is discharged from the impeller 31, a discharge port 15 that discharges the fluid from the spiral chamber 12 to the outside, and a can. A plurality of (six in this embodiment) case female threaded portions 13 to which fastening members 91 for fixing the 60 etc. are tightened, and a support shaft holding portion 14 into which the support shaft 20 is press-fitted. .

The pump casing 10 is formed by die-casting a conductive light metal material, and the pump casing 10 includes a support shaft holding portion 14 having a socket length extending over 40% of the total length of the support shaft 20. are provided integrally. The support shaft 20 has a press-fit portion 21 having a length of 40% or more of the total length, and a support body portion 22 that supports the rotor 20 rotatably. In addition, in this embodiment, the diameter of the support body portion 22 is set larger than the diameter of the press-fitting portion 21 . A thrust washer 23 is passed through the press-fitting portion 21 , and the thrust washer 23 is sandwiched between the support body portion 22 and the support shaft holding portion 14 . is pressed into. Thereby, the support shaft 20 is fixed to the pump casing 10 .

The rotor 30 includes a slide bearing 32 provided on the support body portion 22 of the support shaft 20, an impeller support member 33 provided on the slide bearing 32, an impeller 31 provided on the impeller support member 33, and the impeller 31 and a rotor magnet 34 provided on the impeller support member 33 . The impeller 31 is housed in the spiral chamber 12 and the rotor magnet 34 is arranged on the inner diameter side of the stator 40 .

The stator 40 is arranged radially outward of the rotor 30 . The stator 40 includes a substantially annular stator ring 41, insulating bobbins 42a and 42b provided on the inner diameter side of the stator ring 41, iron cores 43 attached to the insulating bobbins 42a and 42b, A plurality of inwardly directed teeth portions 44 provided, a plurality of yoke portions 45 provided on an iron core 43, electromagnetic coils 46 wound around insulating bobbins 42a and 42b outside the respective teeth portions 44, and these and an energizing terminal 47 for energizing the electromagnetic coil 46 .

In addition, the stator 40 includes a plurality of yoke covering portions 48a and 48b and a plurality of tooth covering portions 49a and 49b extending from both ends of each inward tooth portion 44 of an iron core 43 which is laminated with a magnetic material and to which a plurality of yoke portions 45 are connected. A pair of insulating bobbins 42a and 42b, which are divided into two in the stacking direction, are attached. Further, the stator 40 is formed in an annular shape by winding an electromagnetic coil 46 around insulating bobbins 42a and 42b and fitting it in an annular stator ring 41 having a first fastening flange 41a fixed to the can 60. ing.

The stator 40 is positioned at the axial center of the support shaft 20 through the can 60 by fitting the inner diameter surfaces of the plurality of inward teeth 44 formed in an annular shape to the peripheral surface of the can 60 . ing.

The can 60 has a partitioning flange portion 61 made of resin fixed to the pump casing 10 and a concave portion 62 fitted to the support shaft 20 . is attached to the pump casing 10 so as to cover the A power supply coupler 63 is provided on the partitioning flange portion 61 of the can 60 , and a power supply terminal 64 is provided on the power supply coupler 63 .

The electric water pump 1 positions the can 60 at the axial center of the support shaft 20 with the concave portion 62, and prevents misalignment (center misalignment) between the pump casing 10 and the partition flange portion 61 in the circumferential and radial directions. It has a first play 50 to absorb. The pump casing 10 and the partition flange portion 61 are engaged via a first play 50 .

In addition, the electric water pump 1 positions the stator 40 on the circumferential surface of the can 60 with the inner diameter surfaces of the plurality of inwardly facing teeth 44 , and the stator ring 41 and the can 60 are circumferentially and radially spaced. It has a second play 51 to accommodate directional misalignment. The stator ring 41 and the can 60 are engaged with a second play 51 . In this embodiment, the pump casing 10, the partition flange portion 61, and the first fastening flange 41a of the stator ring 41 are arranged in this order, and the three fastening members 91 are connected to the first fastening flange 41a of the stator ring 41 and the first fastening flange 41a of the stator ring 41. It is passed through each screw insertion hole of the partition flange portion 61 and fastened to three of the six case female screw portions 13 of the pump casing 10 .

A control board 70 for controlling the magnetic field of the stator 40 is held by the second fastening flange 41b, which is the end face of the stator ring 41, via a fixed leg 52 extending from the insulating bobbin 42b. is electrically connected to More specifically, a collar 53 is arranged on the inner diameter side of the fixed leg portion 52 , and a fastening member 92 is inserted through the collar 53 from the control board 70 side and fastened to the second fastening flange 41 b of the stator ring 41 . .

Moreover, the power supply terminal 64 is provided with a stress absorbing portion 65 that can tilt so as to absorb the second play 51 . Further, the insulating bobbin 42 b is provided with a guide portion 54 adjacent to the fixed leg portion 52 and guiding the tip of the power supply terminal 64 to the through hole 71 of the control board 70 .

Further, the electric water pump 1 is provided with a substrate housing 80 made of a conductive metal material and formed in a so-called bathtub shape having a bottom wall and a peripheral wall so as to liquid-tightly cover the control substrate 70 and the stator 40 . It is The substrate housing 80 is fixed to the pump casing 10 so as to sandwich the partition flange portion 61 . A conductive collar member 66 is interposed between the fastening member 91 and the partitioning flange portion 61 to allow the first play 50 while being fastened to the remaining three portions of the portion 13 .

Heat dissipation grease (not shown) is applied between the control board 70 and the bottom wall of the board housing 80 so that the control board 70 and the board housing 80 are in close contact with each other so as to be heat conductive. A first sealing member 81 is provided between the can 60 and the pump casing 10 . Further, a second seal member 82 is provided outside the control board 70 between the board housing 80 and the partitioning flange portion 61 .

Next, fitting between the support shaft 20 and the concave portion 62 of the can 60 will be described. As shown in FIG. 3( a ), the can 60 is positioned at the axial center of the support shaft 20 by fitting the concave portion 62 onto the support shaft 20 . A chamfer 24 is formed at the tip of the support body portion 22 of the support shaft 20 , and a minute gap 25 is formed between the outer peripheral surface of the support body portion 22 and the recess 62 . The tip of the support shaft 20 can be guided into the recess 62 by the chamfer 24, and since there is only a minute gap 25 between the outer peripheral surface of the support shaft 20 (support body portion 22) and the recess 62, the support shaft 20 The concave portion 62 (can 60) is positioned with high precision.

Next, another aspect of the fitting portion will be described. As shown in FIG. 3B, a stepped portion 62a having an inner diameter smaller than the inner diameter of the opening is formed in the middle of the recess 62. As shown in FIG. The chamfer 24 of the support shaft 62 abuts against the stepped portion 62a, so that the concave portion 62 (can 60) is centered with respect to the support shaft 20 and positioned with high accuracy.

Next, how to prevent rotation of the thrust washer 23 will be described. As shown in FIG. 4, the thrust washer 23 is a so-called stepped washer, and a stepped portion 23a is formed in the inner diameter portion. On the other hand, in the support shaft 20, the diameter of the support body portion 22 is set larger than the diameter of the press-fit portion 21, so that the boundary between the press-fit portion 21 and the support body portion 22 is a step. Here, since the thrust washer 23 forms a sliding surface with the slide bearing 32 when the electric water pump 1 (see FIG. 1) is driven, it is necessary to prevent rotation. is press-fitted into the support shaft holding portion 14 and the thrust washer 23 is also sandwiched at the same time, the rotation of the thrust washer 23 is prevented.

Specifically, when the stepped portion 23a of the thrust washer 23 contacts the boundary between the press-fitting portion 21 and the support main body portion 22, the contact area between the support shaft 20 and the thrust washer 23 increases, resulting in a detent force. becomes larger. Furthermore, by buckling the stepped portion 23a, the anti-rotation force is further increased. In the conventional thrust washer, the end portion of the stepped portion 23a on the side of the support shaft holding portion 14 is formed in a hexagonal shape, a D-shape (also called a D-cut), or a non-circular cross-sectional shape formed by a keyway or the like to prevent rotation. However, in this embodiment, the non-circular cross-sectional shape is eliminated, simplifying the shape of the support shaft 20 and reducing the machining cost.

Although the thrust washer 23 is a stepped washer in the embodiment, the thrust washer 23 is not limited to this, and a non-stepped thrust washer 23 may be used. Further, a groove may be added to the support shaft holding portion 14 to form a detent so as to engage the thrust washer 23 and the support shaft holding portion 14. In this case, the stepped portion 23a is eliminated. It is also possible to further simplify the shape of the support shaft 20 and reduce the processing cost by adopting a straight shape.

Next, the action of the electric water pump 1 described above will be described. As shown in FIGS. 1 to 4, the support shaft 20 is press-fitted into the pump casing 10 to maintain high shaft accuracy. A cylindrical recess 62 is provided in the center of the can 60 so that it can be positioned with respect to the support shaft 20. Since the can 60 can be assembled along the outer diameter of the support shaft 20, the coaxial accuracy of the can 60 is improved. Furthermore, the stator 40 is externally fitted to the peripheral surface of the can 60 with the inner diameter surface of the inward tooth portion 44 formed in an annular shape. That is, the can 60 and the stator 40 are assembled and fitted with the support shaft 20 as a reference. In this way, since the rotating system parts are sequentially fitted with the support shaft 20 as a reference, the coaxial accuracy is improved and the variation in performance can be reduced.

Further, the support shaft 20 is made of a rust-resistant and heat-resistant alloy steel such as stainless steel, and is press-fitted into the pump casing 10 made by, for example, an aluminum die-casting method to fix the metals together. It is possible to prevent deterioration in durability due to changes in thermal expansion over time and wear of the shaft, thereby maintaining high coaxial accuracy for a long period of time. For example, the support shaft 20 may be made of stainless steel such as SUS304, and the pump casing may be made of an aluminum alloy.

Next, an outline of the procedure for assembling the electric water pump 1 will be described. The support shaft 20 is press-fitted into the pump casing 10 and fixed. The rotor 30 having the impeller 31 is inserted into the support shaft 20 with the slide bearing 32 interposed therebetween, and the first seal member 81 is assembled to the pump casing 10 . Subsequently, the concave portion 62 of the can 60 is fitted to the support shaft 20 so that the rotor 30 is covered with the pump casing 10 and the can 60 . A conductive collar member 66 is fitted into the screw insertion hole of the can 60 . Separately from this, a stator 40 is produced by attaching a pair of insulating bobbins 42a and 42b to an iron core 43 laminated from a magnetic material and winding an electromagnetic coil 46 thereon, and then connecting the stator 40 in an annular shape. is fitted inside the stator ring 41 . Further, the fastening member 92 is passed through the fixing leg portion 52 provided on the insulating bobbin 42 b of the stator 40 and screwed into the first fastening flange 41 a , thereby fixing the control board 70 to the stator ring 41 .

At this time, the guide portion 54 and the through hole 71 are positioned, and the tip portion of the energizing terminal 47 extending from the stator 40 is inserted through the through hole 71 into the control board 70 .

Next, the inner peripheral surface of the stator 40 to which the control board 70 is fastened as described above is fitted to the peripheral surface of the cylindrical portion of the can 60 covering the rotor 30 . At this time, the substrate-side tip portion of the power supply terminal 64 protruding from the can 60 is inserted through the guide portion 54 of the insulating bobbin 42b and the through hole 71 into the control substrate 70 . Three fastening members 91 are inserted in this order into the first fastening flange 41 a of the stator ring 41 and the conductive collar member 66 interposed in the screw insertion hole of the can 60 , and the fastening members 91 are fastened from the housing 10 . Each member of the can 60 covering the rotor 30 and the stator ring 41 holding the stator 40 is fixed to the housing 10 by fastening to the case female threaded portion 13 .

Further, the conducting terminal 47 and the feeding terminal 64 inserted through the control board 70 are soldered. The second sealing member 82 is interposed between the partitioning flange portion 61 and the substrate housing 80 so that the partitioning flange portion 61 and the substrate housing 80 are brought into contact with each other. 80, the remaining three fastening members 91 are inserted from the screw insertion hole of the substrate housing 80 into the conductive collar member 66 of the screw insertion hole of the can 60 in this order. By fastening 91 to the remaining three case female screw portions 13 of the housing 10, the assembly of the electric water pump 1 is completed.

As described above, according to the present embodiment, the pump casing 10 is formed by die casting of a conductive light metal material, and has a socket length that extends over 40% or more of the total length of the support shaft 20. A support shaft holding portion 14 for holding the support shaft 20 is integrally provided. As a whole, the support shaft 20 press-fitted into the support shaft holding portion 14 of the pump casing 10 is used as a reference, and the concave portion 62 of the can 60 is fitted to the support shaft 20 . Therefore, each member of the pump casing 10, the rotor 30 having the impeller 31, and the can 60 are aligned with the support shaft 20 as a positioning reference.

At this time, since the can 60 is positioned (centered) with the concave portion 62 of the can 60 with respect to the support shaft 20 firmly press-fitted into the pump casing 10 , the can 60 is positioned between the partition flange portion 61 and the pump casing 10 . If there is no so-called "play" that absorbs the deviation, it will not be possible to assemble. In this respect, since the pump casing 10 and the partition flange portion 61 are engaged with the first play 50 that absorbs misalignment, a relatively large air gap between the rotor and the can as in the prior art is not required. . As a result, it is possible to reduce the output loss of the motor due to the conventional air gap, and to improve whirling and speed unevenness that may occur in the rotating system.

Further, the can 60 is positioned (centered) with the concave portion 62 of the can 60 with respect to the support shaft 20 firmly press-fitted and fixed to the pump casing 10, and the stator 40 is attached to the centered can 60. . At this time, the inner diameter surface of the tooth portion 44, which is the magnetic field portion of the stator 40, is fitted into the cylindrical portion (separation wall portion) of the can 60. Assembly becomes difficult if there is no so-called "play" between the ring 41 and the partitioning flange portion 61 of the can 60 to which it is attached. That is, as described above, the three fastening members 91 are inserted in this order into the first fastening flange 41a of the stator ring 41 and the conductive collar member 66 interposed in the screw insertion hole of the can 60. When the fastening members 91 are fastened to the case female screw portion 13 of the housing 10, it becomes difficult to insert the three fastening members 91 into the screw insertion holes.

In this regard, in the present invention, the can 60 and the stator ring 41 are configured to engage with each other with a second play 51 in the circumferential and radial directions. As a result, the support shaft 20, the rotor 30, the can 60, and the stator 40 are all aligned in this order along the support shaft 20 (axis center), so that the output loss of the motor due to the conventional air gap can be further reduced. At the same time, it is possible to further improve whirling and speed unevenness that may occur in the rotating system.

Further, the power supply coupler 63 is provided on the can 60 made of non-magnetic and electrically insulating resin. On the other hand, since the control board 70 needs to be provided near the stator 40 and on the side where the impeller 61 does not exist, the power supply coupler 63 becomes far from the control board 70, so the positional deviation of the power supply terminal 64 with respect to the control board 70 tends to increase. . Furthermore, since a second play 51 is provided between the can 60 and the stator ring 41 that fixes the control board 70, the feed terminal 64 of the feed coupler 63 is arranged so as to absorb the second play 51 as well. need to be When the relative positional relationship between the can 60 and the control board 70 is changed by aligning the can 60 and the stator 40 along the support shaft 20 (axis center), the power supply terminals 64 are aligned with the through holes 71 (power supply terminals) of the control board 70 . This is because it becomes difficult to insert it into the hole for soldering 64 .

In this respect, according to the present invention, the power supply terminal 64 is provided with the tiltable stress absorbing portion 65, and the insulating bobbins 42a and 42b are provided with guide portions (tapered terminal guide holes). can be inserted into

Furthermore, the board housing 80 is fastened to the pump casing 10 by three fastening members 91 . In this case, a first play 50 is provided between the pump casing 10 and the compartment flange portion 61 of the can 60, and a second play 51 is provided between the compartment flange portion 61 and the stator ring 41. If the relative positional relationship between the can 60, the stator ring 41, and the control board 70 with respect to the pump casing 10 changes, the inner wall surface of the board housing 80 interferes with each member, making it difficult to fasten the board housing 80 to the pump casing 10. Become. In this respect, according to the present invention, the third play 55 is formed between the inner wall surface of the substrate housing 80 and the stator 40 and stator ring 41, so that the substrate housing 80 can be easily fastened to the pump casing 10. .

Further, the substrate housing 80 serves as an electromagnetic shield (noise countermeasure member) that separates the electric devices such as the control substrate 70 and the stator 40 from electromagnetic noise sources in the outside world (the electric water pump 1 is mounted in the engine room of an automobile, for example). also works. Therefore, it must be connected to the battery ground. At this time, since the can 60 interposed between the pump casing 10 and the substrate housing 80 is made of non-conductive resin, by interposing the conductive collar member 66 in the screw insertion hole of the can 60, for example, The path to ground may be the board housing 80, the conductive collar member 66, the pump casing 10, the engine block, and the battery.

In the embodiment, the case female threaded portion 13 to which the fastening member 91 for fixing the can 60 and the like is tightened is provided at six locations, but the present invention is not limited to this. As long as the housing 80 can be fixed, the number of case female threaded portions 13 may be increased or decreased as appropriate.

Further, although the socket length of the support shaft holding portion 14 in the embodiment is 40% of the total length of the support shaft 20, the present invention is not limited to this. For example, when the electric water pump is designed to have a higher output and a higher lift, the socket length is set to the total length of the support shaft in order to more firmly fix the support shaft 20 to the pump casing 10 to which a load is applied while the rotor is rotating. Of course, 50%, 60% and 70% may be acceptable.

DESCRIPTION OF SYMBOLS 1... Electric water pump 10... Pump casing 11... Suction port 12... Spiral chamber 15... Discharge port 20... Support shaft 21... Press fitting part 30... Rotor 34... Rotor magnet 40... Stator 41 ... Stator ring 41a... First fastening flange 42a, 42b... Insulating bobbin 43... Iron core 44... Teeth part 45... Yoke part 46... Electromagnetic coil 48a, 48b... Yoke covering part 49a, 49b... Teeth Coating part 50 First play 51 Second play 52 Fixed leg 54 Guide part 60 Can 61 Compartment flange 62 Recess 63 Feed coupler 64 Feed Terminal 66 Conductive collar member 70 Control board 71 Through hole 80 Board housing 91 Fastening member.

Claims (3)

a pump casing having an inlet, an outlet, and a volute;
a rotor having a rotor magnet and an impeller housed in the spiral chamber;
a stator disposed radially outward of the rotor;
a support shaft that is fixed to the pump casing and rotatably supports the rotor;
a resin-made partition flange fixed to the pump casing and a concave portion fitted to the support shaft; An electric water pump comprising a can attached to
The pump casing is formed by die casting of a conductive light metal material, and has a support shaft holding portion that has a socket length that extends over 40% or more of the total length of the support shaft and holds the support shaft. set in one body,
The can is positioned at the axial center of the support shaft by the recess, and the pump casing and the partition flange are engaged with each other via a first play that absorbs positional deviation in the circumferential direction and the radial direction ,
The stator has a plurality of yoke covering portions and a plurality of tooth covering portions on each of the inward tooth portions of an iron core laminated with a magnetic material and having a plurality of yoke portions connected to each other, and is divided into two pieces in the lamination direction. A pair of insulating bobbins are attached, an electromagnetic coil is wound around the insulating bobbins, and an annular stator ring is fitted to the can to form an annular shape,
The stator is positioned at the axial center of the support shaft through the can by fitting the inner diameter surface of the inwardly-shaped tooth portion to the peripheral surface of the can,
An electric water pump , wherein the can and the stator ring are engaged with a second play that absorbs positional deviation in the circumferential and radial directions. The electric water pump according to claim 1 ,
A power supply coupler having a power supply terminal is provided on the partition flange portion of the can,
a control board for controlling the magnetic field of the stator is held on the end surface of the stator ring by a fixed leg provided so as to extend from the insulating bobbin, and is electrically connected to the power supply terminal;
The power supply terminal is provided with a stress absorbing portion capable of tilting so as to absorb the second play, and the insulating bobbin is provided with a tip end of the power supply terminal connected to the through hole of the control board adjacent to the fixed leg. An electric water pump characterized by providing a guide portion for guiding. The electric water pump according to claim 2 ,
A board housing is provided that covers the control board with a conductive metal material,
The pump casing, the partition flange portion, and the substrate housing are arranged in this order and screwed together by a fastening member, and a conductive collar is provided between the fastening member and the partition flange portion to allow the first play. An electric water pump characterized by interposing a member.

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