US20130028761A1

US20130028761A1 - Pump device

Info

Publication number: US20130028761A1
Application number: US13/556,680
Authority: US
Inventors: Mitsuo Yokozawa; Tsutomu Arai
Original assignee: Nidec Sankyo Corp
Current assignee: Nidec Sankyo Corp
Priority date: 2011-07-25
Filing date: 2012-07-24
Publication date: 2013-01-31
Also published as: CN102900690A; CN102900690B; JP2013024217A

Abstract

A pump device may include a stator provided with a stator core having a ring-shaped part on a center side and a drive coil wound around the stator core, and a partition wall disposed configured to separate a pump chamber from the stator. The partition wall is provided with a protruded part in a bottomed tube-like shape which is protruded on an inner side of the ring-shaped part and an outer peripheral face of a tube shaped part structuring the protruded part is formed with a plurality of protruding parts protruding to an outer side in a radial direction. The stator core is fixed to the protruded part in a state that the plurality of the protruding parts is press-fitted to the ring-shaped part.

Description

CROSS REFERENCE TO RELATED APPLICATION

The present invention claims priority under 35 U.S.C. §119 to Japanese Application No. 2011-162569 filed Jul. 25, 2011, the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

At least an embodiment of the present invention may relate to a pump device which is provided with a partition wall partitioning a pump chamber.

BACKGROUND

A vortex pump for pressure-feeding liquid is, for example, disclosed in Japanese Patent Laid-Open No. 2010-119164. The pump device disclosed in the literature is provided with a stator having a stator core around which a drive coil is wound, a rotor having an impeller and a drive magnet in a tube-like shape which surrounds the stator from an outer peripheral side, and a partition wall which is disposed between the stator and the rotor for separating the pump chamber within which the impeller is disposed from the stator. In the pump device disclosed in the literature, the stator is fixed to a base plate through an insulator which is utilized when the drive coil is wound around the stator core and then the stator is fixed to a housing. The housing is a resin molded body in which the stator and the base plate are resin-molded by insert molding and a part of the resin molded body functions as the partition wall.
In the pump device disclosed in the above-mentioned Patent Literature, two members (insulator and base plate) are disposed between the housing and the stator and thus dimensional tolerance and assembling tolerance are accumulated and, as a result, the positional accuracy of the stator with respect to the partition wall may be lowered. When the positional accuracy of the stator with respect to the partition wall is lowered, it is difficult to control a gap between the stator having the drive coil and the drive magnet of the rotor facing each other through the partition wall and thus it is difficult to maintain the performance of a manufactured pump device to be substantially the same.

SUMMARY

In view of the problem described above, at least an embodiment of the present invention may advantageously provide a pump device in which the stator is capable of being positioned and fixed with a high degree of accuracy with respect to the partition wall separating the stator from the rotor.
According to at least an embodiment of the present invention, there may be provided a pump device including a stator provided with a stator core having a ring-shaped part on a center side and a drive coil which is wound around the stator core, a rotor provided with an impeller and a drive magnet which faces the stator through a predetermined distance on an outer peripheral side of the stator, and a partition wall which is disposed between the stator and the rotor for separating a pump chamber in which the impeller is disposed from the stator. The partition wall is provided with a protruded part in a bottomed tube-like shape which is protruded on an inner side of the ring-shaped part, an outer peripheral face of a tube shaped part structuring the protruded part is formed with a plurality of protruding parts which protrude from parts in a circumferential direction to an outer side in a radial direction, and the stator core is fixed to the protruded part in a state that a plurality of protruding parts is press-fitted to the ring-shaped part.
According to at least an embodiment of the present invention, the stator is directly fixed to the partition wall separating the stator from the rotor. Therefore, positional accuracy of the stator with respect to the partition wall can be enhanced. Further, different from a case that the stator core is fixed to the partition wall in a state that the entire periphery in the circumferential direction of the protruded part is press-fitted to the ring-shaped part, the stator core is fixed to the partition wall in a state that a plurality of the protruding parts provided on the outer peripheral face of the tube shaped part of the protruded part is press-fitted to the ring-shaped part and thus a press-fitting margin between the partition wall and the stator core is small. As a result, the stator core is easily press-fitted when the stator core is to be fixed to the partition wall and thus positional accuracy of the stator with respect to the partition wall can be enhanced even when the stator is press-fitted and fixed to the partition wall. Therefore, a gap space between the stator core of the stator and the drive magnet of the rotor which face each other through the partition wall can be controlled with a high degree of accuracy.
In accordance with at least an embodiment of the present invention, an inner peripheral face of the ring-shaped part of the stator core is provided with a plurality of recessed parts to which each of a plurality of the protruding parts is capable of being press-fitted, and the protruding parts are press-fitted to the recessed parts. According to this structure, the stator (stator core) is positioned around the axial line “L” by press-fitting the protruding part to the recessed part. Further, when the rotor provided with the impeller is rotated by the magnetic drive mechanism structured of the drive coil, the stator core and the drive magnet, the stator is prevented from being turned around the axial line “L” by the reaction force. In addition, since a plurality of the protruding parts provided on the outer peripheral face of the protruded part is press-fitted to the recessed parts provided in the ring-shaped part, stress at the time of press-fitting is easily released from each of the protruding parts to the circumferential direction of the protruded part. Therefore, deformation and damage of the partition wall can be prevented when the stator is press-fitted and fixed.
In this case, it is preferable that both side portions in the circumferential direction of the protruding part are press-fitted to the recessed part, and a clearance is provided between a tip end on an outer side in the radial direction of the protruding part and the recessed part. According to this structure, stress is restrained from occurring in the radial direction of the protruded part at the time of press-fitting and fixing. Therefore, deformation and damage of the partition wall can be prevented.
In accordance with at least an embodiment of the present invention, the plurality of the protruding parts is formed in the same shape and is disposed at three or more positions at an equal angular interval. According to this structure, when a plurality of protruding parts is press-fitted to the ring-shaped part, concentricity of the protruded part of the partition wall with the stator core is improved and thus the positional accuracy of the stator with respect to the partition wall is improved.
In accordance with at least an embodiment of the present invention, the protruding part is extended in an axial line direction along the outer peripheral face of the tube shaped part and is provided with a tapered face whose protruding amount to an outer side in the radial direction and to the circumferential direction is increased from a side of a bottom part of the protruded part in the bottomed tube-like shape toward a side of an opening end of the protruded part, and a part of the protruding part on the side of the opening end is press-fitted to the ring-shaped part of the stator core. According to this structure, the protruding part is easily press-fitted to the ring-shaped part of the stator core. Further, only a part of the protruding part is press-fitted to the ring-shaped part of the stator core and thus a press-fitting margin can be reduced.
In accordance with at least an embodiment of the present invention, the partition wall is provided with a cylindrical tube part provided on an outer peripheral side of the protruded part and a circular ring-shaped part which connects an opening end of the protruded part with the cylindrical tube part, the stator is accommodated in a circular ring-shaped recessed part for accommodating the stator which is formed of the protruded part, the cylindrical tube part and the circular ring-shaped part, and the stator is covered by a sealing agent which is poured into the circular ring-shaped recessed part for accommodating the stator. According to this structure, even when a press-fitting margin between the partition wall and the stator core is small, the stator can be surely fixed to the partition wall by the sealing agent.
In this case, it is preferable that the protruded part in the bottomed tube-like shape is provided with a protruding portion which protrudes in an axial line direction from an opening of the circular ring-shaped recessed part for accommodating the stator on a bottom part side of the protruded part, and an end of the protruding part on the bottom part side of the protruded part is reached to the protruding portion. According to this structure, the ends of the protruding parts which are reached to the protruding portion are respectively fitted to the recessed parts of the ring-shaped part of the stator core and, after that, the stator is guided by the protruding parts and is accommodated in the stator accommodating room.
Further, in this case, it is preferable that the partition wall is a resin molded product, and an inner peripheral face of the tube shaped part structuring the protruded part is formed with a groove at a position corresponding to the protruding part formed on the outer peripheral face of the tube shaped part. According to this structure, a thickness of the tube shaped part of the protruded part can be set almost uniform over the entire periphery and thus shrinkage occurred in the protruded part when the partition wall is molded can be set uniform. Therefore, the cylindricality of the protruded part is improved.
In accordance with at least an embodiment of the present invention, an outer peripheral face of the tube shaped part structuring the protruded part is provided with a positioning part which is abutted with the ring-shaped part of the stator core from a side of an opening end of the protruded part in the bottomed tube-like shape for positioning the stator in an axial line direction, and the positioning part and the protruding part are formed at a separated position from each other in a circumferential direction. According to this structure, positioning of the stator in the axial line direction is easily performed.
In accordance with at least an embodiment of the present invention, a support shaft which rotatably supports the rotor is fixed to an inner side face of the bottom part of the protruded part. According to this structure, both of the support shaft supporting the rotor and the stator are fixed to the protruded part and thus a relative positional accuracy of the rotor supported by the support shaft to the stator is improved.
Further, in accordance with at least an embodiment of the present invention, a support shaft which rotatably supports the rotor is fixed to an inner side face of the bottom part of the protruded part, the rotor is provided with a bearing part in a tube-like shape, the bearing part is disposed on an inner side of the protruded part in a state that the support shaft is inserted into a center hole of the bearing part, a washer for adjusting a position in the axial line direction of the rotor is fitted between the bottom part of the protruded part and the bearing part, the washer is formed with a turning prevention part protruding to an outer side in the radial direction from an outer circumferential edge portion of the washer, and the turning prevention part is fitted to the groove formed on the inner peripheral face of the tube shaped part. According to this structure, a relative positional adjustment of the rotor to the stator in the axial line direction can be performed by fitting of the washer. Further, since the turning prevention part and the groove are engaged with each other, the washer is prevented from being turned around the axial line when the rotor is rotated.
Further, the pump device in accordance with at least an embodiment of the present invention may include a first case which structures the partition wall and is provided with a circular ring-shaped protruded part on an inner side of an outer peripheral wall, a second case which is provided with a circular ring-shaped stepped part into which the circular ring-shaped protruded part is coaxially inserted and which partitions the pump chamber on an inner peripheral side of the circular ring-shaped stepped part together with the first case, and an O-ring which is attached on a circular outer peripheral face of the circular ring-shaped protruded part and is crushed between the circular outer peripheral face of the circular ring-shaped protruded part and a circular inner peripheral face of the circular ring-shaped stepped part in a direction perpendicular to an axial line of the circular ring-shaped protruded part.
Further, in accordance with at least an embodiment of the present invention, the second case includes a bottom plate part, a side wall part in a ring shape which is stood up from an outer peripheral side portion of the bottom plate part, and a circular recessed part which is formed of the bottom plate part and the side wall part. An inner peripheral face on an upper side of the side wall part is formed with the circular ring-shaped stepped part, and a liquid flow passage is structured between the circular ring-shaped protruded part of the first case and the circular recessed part of the second case at a position on an inner side with respect to the circular ring-shaped stepped part.
Other features and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings that illustrate, by way of example, various features of embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:

FIGS. 1( a), 1(b) and 1(c) are perspective views and a front view showing a pump device in accordance with an embodiment of the present invention.

FIGS. 2( a) and 2(b) are cross-sectional views showing a pump device in accordance with an embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a pump device in accordance with an embodiment of the present invention.

FIG. 4( a) is a perspective view showing a rotor and FIG. 4( b) is a perspective view showing a stator.

FIGS. 5( a) and 5(b) are perspective views showing a lower case.

FIGS. 6( a) and 6(b) are perspective views showing an upper case.

FIGS. 7( a) and 7(b) are partly enlarged perspective views showing a stator accommodating room of an upper case and the like.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A pump device in accordance with an embodiment of the present invention will be described below with reference to the accompanying drawings. In the following description, for convenience of explanation, upper and lower sides of a pump device are described according to an upper and lower direction in the drawing. Further, a side from which a suction pipe and a discharge pipe are protruded is referred to as a front side of the pump device and its opposite side is referred to as a rear side and an arrangement direction of the suction pipe and the discharge pipe is referred to as a widthwise direction of the device.
(Entire Structure)
FIG. 1( a) is a perspective view showing a pump device in accordance with an embodiment of the present invention which is viewed from a forward oblique upper side, FIG. 1( b) is a perspective view showing the pump device which is viewed from a rearward oblique upper side, and FIG. 1 (c) is a front view showing the pump device. A pump device 1 in accordance with an embodiment of the present invention is a vortex pump which pressure-feeds liquid such as refrigerant. The pump device 1 is provided with a pump case 2 which is formed in a flat rectangular prism shape as a whole. The pump case 2 is made of resin such as PPS (polyphenylene sulfide). A suction pipe 3 and a discharge pipe 4 are protruded in parallel toward the front side from a front face 2 a of the pump case 2. A wiring outlet part 6 for taking out lead wires 5 from an inner side of the pump case 2 is provided at a corner portion 2 b located on a front left side between the front face 2 a of the pump case 2 and a side face adjacent to the front face 2 a in a clockwise direction. The lead wires 5 are extended out from a midway position in an axial line “L” direction (height direction) of the pump device 1 through the wiring outlet part 6 toward an obliquely front side. The lead wires 5 are extended longer than the suction pipe 3 and the discharge pipe 4 and a connector 7 is attached to tip ends of the lead wires 5.
An inclined face 2 c (see FIG. 1( c)) intersecting the front face 2 a and the side face and extending in the axial line “L” direction is formed at the corner portion 2 b located on the front left side of the pump case 2 where the wiring outlet part 6 is provided by obliquely cutting out a tip end of the corner portion 2 b. Further, a hook 8 is provided at the corner portion 2 b located on the front left side for locking the lead wires 5 when the lead wires 5 are extended out along the inclined face 2 c. The hook 8 is extended in a direction perpendicular to the axial line “L” at a center position in the axial line “L” direction of the inclined face 2 c so as to have a predetermined space between the inclined face 2 c and the hook 8. Further, the hook 8 is extended with a constant width from the front face 2 a side toward the side face.
The pump case 2 is structured of a lower case (second case) 11 and an upper case (first case or partition wall) 12 which are superposed on each other in the upper and lower direction. The suction pipe 3 and the discharge pipe 4 are protruded from the front face of the lower case 11. The wiring outlet part 6 is structured at the corner portion on the front left side of the upper case 12. The hook 8 is provided on the lower case 11. In this embodiment, a corner portion 2 f on the rear right side of the pump case 2 which is located at a position diagonal to the wiring outlet part 6 is provided with a turning prevention mechanism 13 for preventing relative turning of the lower case 11 to the upper case 12 when the lower case 11 and the upper case 12 are superposed on each other.
FIG. 2( a) is a longitudinal sectional view showing the pump device 1 which is cut by the “X-X” line in FIG. 1( a) and FIG. 2( b) is a longitudinal sectional view showing the pump device 1 which is cut by the “Y-Y” line in FIG. 1( a). FIG. 3 is an exploded perspective view showing the pump device 1. FIG. 4( a) is a perspective view showing a rotor and FIG. 4( b) is a perspective view showing a stator.
As shown in FIGS. 2( a) and 2(b) and FIG. 3, the lower case 11 and the upper case 12 are superposed on each other in a partially overlapped state in a direction perpendicular to axial line “L”. A partitioned chamber 20 for accommodating a rotor and for forming a pump chamber is structured between the lower case 11 and the upper case 12. A rotor 23 provided with a circular ring-shaped impeller 21 and a drive magnet 22 and a support shaft 24 which rotatably supports the rotor 23 are disposed in the partitioned chamber 20. Further, an outer peripheral side portion of the partitioned chamber 20 is structured to be a circular ring-shaped pump chamber 25 through which liquid is pressure-fed by the impeller 21 and the impeller 21 structuring the rotor 23 is disposed within the pump chamber 25. An O-ring 26 is disposed between the lower case 11 and the upper case 12 for preventing leakage of liquid from the partitioned chamber 20. A stator 29 provided with a drive coil 27 and a stator core 28 on which the drive coil 27 is mounted and a base plate 30 are disposed on an upper side of the upper case 12 which is opposite to the side where liquid is pressure-fed, in other words, on an opposite side to the partitioned chamber 20 with respect to the upper case 12 (opposite side to the lower case 11). The drive magnet 22, the stator core 28, and the drive coil 27 wound around the stator core 28 structure a magnetic drive mechanism for rotationally driving the impeller 21.
A liquid flow passage 31 is formed on a bottom face and a ceiling face of the pump chamber 25 over a predetermined angular range around the axial line “L”. More specifically, a lower side liquid flow passage 31 a formed of a circular arc groove having a semicircular cross-sectional shape is formed on the bottom face of the pump chamber 25 which is structured of the lower case 11, and an upper side liquid flow passage 31 b formed of a circular arc groove having a semicircular cross-sectional shape is formed on the ceiling face of the pump chamber 25 which is structured of the upper case 12. The lower side liquid flow passage 31 a and the upper side liquid flow passage 31 b are superposed on each other when viewed in the axial line “L” direction. In this embodiment, the liquid flow passage 31 is formed over an angular range approximately larger than 270° around the axial line “L”.
In the pump chamber 25, a suction port 3 a (see FIG. 5( a)) which is in communication with the suction pipe 3 is provided at a portion of the lower case 11 where one end of the liquid flow passage 31 is located and a discharge port 4 a (see FIG. 5( a)) which is in communication with the discharge pipe 4 is provided at a portion of the lower case 11 where the other end of the liquid flow passage 31 is located. A portion of the bottom face of the pump chamber 25 which is located between the suction port 3 a and the discharge port 4 a is formed as a lower side blocking part 32 a where the lower side liquid flow passage 31 a is not formed. Similarly, a portion of the ceiling face of the pump chamber 25 which is located between the suction port 3 a and the discharge port 4 a is formed as an upper side blocking part 32 b where the upper side liquid flow passage 31 b is not provided.
A support shaft 24 is made of stainless steel and its lower end portion is fixed to a support shaft fixing recessed part 60 which is provided in the lower case 11. Further, its upper end portion is fixed to a support shaft fixing recessed part 82 which is provided at a center of a bottom part 81 of a center protruded part 80 formed in a bottomed tube-like shape that is provided at the center portion of the upper case 12. The support shaft fixing recessed part 82 is provided at a center of an inner side face of the bottom part 81.
The rotor 23 is provided with, as shown in FIG. 4( a), a disk part 40, a bearing part 41 in a cylindrical tube shape which is protruded upward from a center of an upper face of the disk part 40, and a magnet holding cylindrical tube part 42 which is protruded upward from the upper face of the disk part 40 so as to coaxially surround the bearing part 41 with a predetermined distance from the bearing part 41, which are made of resin such as PPS. The predetermined distance between the bearing part 41 and the cylindrical tube part 42 is a distance in which the stator 29 is capable of being accommodated therebetween through the upper case 12. The rotor 23 is rotatable around the axial line “L” of the support shaft 24 in a state that the support shaft 24 is inserted into a center hole 41 a of the bearing part 41 and the bearing part 41 is disposed on an inner side of the center protruded part 80 of the upper case 12. One piece or plural pieces of the washer 43 is fitted between an upper end of the bearing part 41 and the bottom part 81 of the center protruded part 80 and the position of the rotor 23 in the axial line “L” direction with respect to the stator 29 is adjusted by fitting of the washer 43 (see FIGS. 2( a) and 2(b)). In this embodiment, two pieces of the washer are used. For example, when one or two pieces of a washer 43 whose thickness is 0.2 mm and a washer 43 whose thickness is 0.3 mm are selected, a total thickness of the washers 43 can be adjusted in a range from 0.2 mm to 0.6 mm with an interval of 0.1 mm.
A yoke 44 in a cylindrical tube shape is held by an inner peripheral face of the magnet holding cylindrical tube part 42 and the drive magnet 22 in a cylindrical tube shape is held by an inner peripheral face of the yoke 44. The yoke 44 is integrally formed with the rotor 23 by insert molding and the drive magnet 22 is adhesively fixed to the yoke 44. An outer peripheral portion on an outer peripheral side in the disk part 40 with respect to the cylindrical tube part 42 is structured as the impeller 21.
An outer peripheral portion of the impeller 21 is formed with recessed parts 45 which are formed in two rows in the upper and lower direction at an equal angular interval in the circumferential direction. The recessed parts 45 are provided with upper side recessed parts 46, which are formed by cutting a circumferential edge of an upper face of the disk part 40 in a circular arc shape, and lower side recessed parts 47 which are formed by cutting a circumferential edge of an under face of the disk part 40 in a circular arc shape. Portions between the recessed parts 45 adjacent to each other in the circumferential direction are formed as blades 48 which are respectively extended in a radial direction. A portion between the upper side recessed parts 46 and the lower side recessed parts 47 which are adjacent to each other in the upper and lower direction is extended in the circumferential direction and is formed to be a rib 49 partitioning the respective blades 48 in the upper and lower direction. The impeller 21 is, as shown in FIGS. 2( a) and 2(b), disposed in the pump chamber 25.
The stator 29 is disposed within a stator accommodating room (stator accommodating circular ring-shaped recessed part) 83 which is formed in a circular ring-shaped recessed part and is provided on an outer peripheral side of the center protruded part 80 and on an upper face side of the upper case 12. A stator core 28 is, as shown in FIG. 4( b), provided with a ring-shaped part 50 on its center side and a plurality of salient poles 51 which is protruded from the ring-shaped part 50 to an outer side in the radial direction. A drive coil 27 is wound around each of a plurality of the salient poles 51. As shown in FIGS. 2( a) and 2(b), each of the salient poles 51 is oppositely disposed through the upper case 12 in a direction perpendicular to the axial line “L” to the drive magnet 22 of the rotor 23 which is disposed within the partitioned chamber 20 that forms a magnet accommodating space in which the circular ring-shaped drive magnet 22 is accommodated. The upper case 12 is disposed between the rotor 23 and the stator 29 to be functioned as a partition wall separating the pump chamber 25 and the magnet accommodating space from the stator 29.
The stator core 28 is structured so that a plurality of plate-shaped core pieces 52 having the same shape which are formed by die cutting of a thin plate-shaped magnetic steel plate is laminated in the upper and lower direction and a laminated direction of the plate-shaped core pieces 52 is the axial line “L” direction. An inner peripheral face of the ring-shaped part 50 of the stator core 28 is formed with three inner side recessed parts 53 whose cross-sectional shape in a direction perpendicular to the axial line “L” is a circular arc contour shape at an equal angular interval around the axial line “L”. Three inner side recessed parts 53 are the same shape and are extended in the axial line “L” direction. The depths in the radial direction of the respective inner side recessed parts 53 are the same as each other and its cross-sectional shape is the same as each other at each position in the axial line “L” direction.
A base plate 30 is disposed in an upper space 87 which is provided on an inner side of a frame-shaped outer peripheral wall 86 protruding from an upper face of the upper case 12 to an upper side along its circumferential edge. The base plate 30 serves as a circuit board for supplying an electric current to the drive coil 27 wound around the stator core 28 and covers the stator 29 disposed within the stator accommodating room 83 from the upper side. A face on the stator core 28 side of the base plate 30 is connected with the lead wires 5, which are drawn out to an outer side of the pump case 2 through the wiring outlet part 6. The wiring outlet part 6 is, as shown in FIG. 3, provided with a wiring outlet port 33 which is formed by cutting out an outer peripheral wall 86, a wire placing part 34 for arranging and placing the lead wires 5 in one row which are drawn out from the inner side of the pump case 2 to the outer side through the wiring outlet port 33, and a fixing member 35 which is fixed to the upper case 12 so as to close the wiring outlet port 33 from the upper side of the base plate 30 for sandwiching the lead wires 5 arranged on the wire placing part 34 between the wire placing part 34 and the fixing member 35 and thereby their coatings are fixed in a pressed state.
In this embodiment, as shown in FIGS. 1( a) and 1(b), a potting agent 16 (sealing agent) is poured into the stator accommodating room 83 and the upper space 87 of the upper case 12 so as to reach the upper end of the outer peripheral wall 86 and thus the stator 29 and the base plate 30 are covered and fixed by the potting agent 16. The potting agent 16 is resin having insulation property such as epoxy, acrylic, or silicon resin.
When an exciting current is supplied to the drive coil 27 from the connector 7 through the lead wires 5 and the base plate 30, the rotor 23 is rotated around the axial line “L”. As a result, liquid is sucked into the pump chamber 25 through the suction pipe 3, pressurized in the pump chamber 25 and then discharged from the discharge pipe 4. The motor (rotor 23, stator 29 and base plate 30) which drives the pump device 1 in this embodiment is a three-phase brushless motor and three Hall elements not shown for detecting a position of the drive magnet 22 of the rotor 23 are disposed on the base plate 30. When the order of an exciting current supplied to the drive coil 27 is reversed, the rotor 23 is rotated in the reverse direction and thus, liquid is sucked through the discharge pipe 4, pressurized in the pump chamber 25 and then discharged from the suction pipe 3.
(Lower Case)
FIG. 5( a) is a perspective view showing the lower case 11 which is viewed from an upper side and FIG. 5( b) is a perspective view showing the lower case 11 which is viewed from a lower side. The lower case 11 is provided with a bottom plate part 61, a ring shaped side wall part 62 which is stood up from an outer peripheral side portion of the bottom plate part 61 so as to extend to an upper side, and a circular recessed part 63 which is formed by the bottom plate part 61 and the side wall part 62. A contour shape of the side wall part 62 which is viewed in the axial line “L” direction is a substantially rectangular shape and a planar shape of the lower case 11 viewed in the axial line “L” direction is a substantially rectangular shape. The side wall part 62 is provided with a flat upper end face 62 a and the upper end face 62 a is an upper end face of the lower case 11. The pump chamber 25 is structured so as to be a ring shape along the circumferential edge of the circular recessed part 63. A support shaft fixing recessed part 60 is provided at the center of a circular bottom face of the circular recessed part 63.
A circular ring-shaped recessed part 64 is formed on an outer peripheral side of the support shaft fixing recessed part 60 coaxially with the support shaft fixing recessed part 60. A portion between the support shaft fixing recessed part 60 and the circular ring-shaped recessed part 64 is formed to be an inner side ring-shaped protruded face 65 and a portion on an outer peripheral side of the circular ring-shaped recessed part 64 is formed to be an outer side ring-shaped protruded face 66. The outer side ring-shaped protruded face 66 structuring the circular recessed part 63 is formed with a lower side liquid flow passage 31 a structuring a bottom face of the pump chamber 25 and a lower side blocking part 32 a along its circumferential edge. A circular ring-shaped end face portion 67 of the outer side ring-shaped protruded face 66 which is adjacent to the inner side of pump chamber 25 faces the disk part 40 of the rotor 23 which is disposed within the partitioned chamber 20 through a minute gap “G1” (see FIGS. 2( a) and 2(b)). In the circular ring-shaped end face portion 67, two grooves 67 a having a constant width by which the lower side liquid flow passage 31 a is in communication with the circular ring-shaped recessed part 64 are formed at positions separated from each other by 180°
A circular ring-shaped stepped part 68 is provided on an upper side portion of the circular recessed part 63, in other words, on an inner peripheral face of an upper side portion of the side wall part 62. The circular ring-shaped stepped part 68 is provided with a circular ring-shaped end face 68 a, which is extended in a radial direction from a midway position in the axial line “L” direction of the inner peripheral face of the side wall part 62, and a circular inner peripheral face 68 b which is extended to an upper side from an outer circumferential edge of the circular ring-shaped end face 68 a. The circular ring-shaped stepped part 68 forms a circular recessed part having a diameter larger than a circular recessed part 63 on an upper end portion of the lower case 11.
The suction pipe 3 and the discharge pipe 4 are protruded in parallel from the front face of the side wall part 62. An inclined face 2 c and a hook 8 are provided at the corner portion 2 b of the lower case 11 on the front left side which is adjacent to the discharge pipe 4 of the side wall part 62. A turning prevention recessed part 69 structuring the turning prevention mechanism 13 is provided at a corner portion 2 f on the rear right side of the side wall part 62. The turning prevention recessed part 69 is a recessed part which is recessed to a lower side from the upper end face 62 a. Further, the turning prevention recessed part 69 is cut out from the outer peripheral side and its inner peripheral face is exposed to the outer side of the lower case 11.
(Upper Case)
FIG. 6( a) is a perspective view showing the upper case 12 which is viewed from an upper side and FIG. 6( b) is a perspective view showing the upper case 12 which is viewed from a lower side. The upper case 12 is, as shown in FIG. 6( a), provided with a center protruded part 80 to which the ring-shaped part 50 of the stator core 28 is fitted, a cylindrical tube part 89, which is coaxially structured with the center protruded part 80 and with which the outer peripheral faces of the salient poles 51 of the stator core 28 are abutted, and an inner side ring-shaped part 90 which connects an opening end of the center protruded part 80 with a lower end part of the cylindrical tube part 89. Further, the upper case 12 is, as shown in FIG. 6( b), provided with a circular ring-shaped protruded part 91, which is coaxially structured with the center protruded part 80 and the cylindrical tube part 89 on an outer peripheral side of the cylindrical tube part 89 and is protruded to a lower side, an outer side ring-shaped part 92, which connects an upper end part of the cylindrical tube part 89 with an upper end part of the circular ring-shaped protruded part 91, and a projecting part 93 which projects from an upper end part of the circular ring-shaped protruded part 91 to an outer peripheral side.
A contour shape of the projecting part 93 is a roughly rectangular shape and the corner portion 2 b on the front left side is cut out obliquely to form the inclined face 2 c. The outer peripheral wall 86 for partitioning an upper space 87 in which the base plate 30 is disposed is protruded to the upper side from an outer circumferential edge of the projecting part 93 except the corner portion 2 b on the front left side which is provided with the cut-out portion. In the corner portion 2 b on the front left side having the cut-out portion, the outer peripheral wall 86 is located at an inner position from an outer circumferential edge of the projecting part 93. Further, in the corner portion 2 b on the front left side, the outer peripheral wall 86 is cut out with a constant width in a rectangular shape and the cut-out part is formed as the wiring outlet port 33. A portion between the wiring outlet port 33 and the outer circumferential edge of the projecting part 93 is the wire placing part 34. An upper face of the wire placing part 34 is formed with wire holding grooves 36 a whose cross section is a circular arc shape and which are extended in parallel to an outer side in the radial direction so as to correspond to the number of the lead wires 5. Further, an under face of the fixing member 35 is formed with wire holding grooves 36 b corresponding to the wire holding grooves 36 b (see FIG. 1( c)). The lead wires 5 are sandwiched between the wire holding grooves 36 a and the wire holding grooves 36 b in the upper and lower direction and are fixed in a state that their coatings are pressed.
The corner portion 2 f on the rear right side of the projecting part 93 located at a diagonal position to the wiring outlet part 6 is formed with a turning preventing protruded part 97 in a circular cylindrical shape which is protruded to the lower case 11 side. The turning preventing protruded part 97 is capable of being fitted to the turning prevention recessed part 69 provided in the lower case 11 and structures the turning prevention mechanism 13 together with the turning prevention recessed part 69.
The stator accommodating room 83 in which the stator 29 is disposed is structured of faces of the center protruded part 80, the cylindrical tube part 89 and the inner side ring-shaped part 90 on an opposite side with respect to the lower case 11. The center protruded part 80 is provided with a protruding portion 80 a, which is protruded to an upper side from an opening of the stator accommodating room 83, on a side of the bottom part 81. A thickness in the radial direction of the cylindrical tube part 89 is formed thinner than a thickness in the radial direction of the center protruded part 80.
A circular ring-shaped lower end face 94 of the circular ring-shaped protruded part 91 is formed with an upper side liquid flow passage 31 b and an upper side blocking part 32 b, which structures a ceiling face of the pump chamber 25, at a midway position in the radial direction on an inner side with respect to the circular ring-shaped stepped part 68. In the circular ring-shaped lower end face 94, a circular ring-shaped end face portion 94 a which is adjacent to an inner side of the pump chamber 25 faces the disk part 40 of the rotor 23 disposed within the partitioned chamber 20 through a minute gap “G2” (see FIGS. 2( a) and 2(b)2).
A radial direction protruded part 96 protruding to an outer side by a predetermined dimension in the radial direction is provided on an upper end portion of a circular outer peripheral face 95 of the circular ring-shaped protruded part 91. The radial direction protruded part 96 is provided with a circular ring-shaped end face 96 a, which is extended to an outer side in the radial direction from a midway position in the axial line “L” direction of the circular ring-shaped protruded part 91 so as to face the lower case 11, and a circular outer peripheral face 96 b which is extended to an upper side from an outer circumferential edge of the circular ring-shaped end face 96 a so as to face the outer side in the radial direction.
In this embodiment, when the upper case 12 and the lower case 11 are to be superposed on each other to partition the pump chamber 25 (partitioned chamber 20), an O-ring 26 is mounted on the circular outer peripheral face 95 of the circular ring-shaped protruded part 91 of the upper case 12. In this case, a lubricant is applied to the O-ring 26. Further, the support shaft 24 is previously fixed to the support shaft fixing recessed part 82 of the upper case 12 and the rotor 23 is disposed in the circular recessed part 63 of the lower case 11 so that the support shaft 24 is capable of being inserted into the bearing part 41. Next, the circular ring-shaped protruded part 91 of the upper case 12 is inserted into the inner side of the circular ring-shaped stepped part 68 of the lower case 11. After that, the upper case 12 and the lower case 11 are relatively come close to each other so that the circular ring-shaped lower end face 94 of the circular ring-shaped protruded part 91 (circular ring-shaped end face portion which is located on the outer peripheral side with respect to the upper side liquid flow passage 31 b and the upper side blocking part 32 b) is abutted with the circular ring-shaped end face 68 a of the circular ring-shaped stepped part 68 of the lower case 11.
In this case, the circular outer peripheral face 96 b of the radial direction protruded part 96 of the upper case 12 is abutted with the circular inner peripheral face 68 b of the circular ring-shaped stepped part 68 of the lower case 11 and thus the upper case 12 is positioned in the radial direction by the lower case 11. Further, the O-ring 26 is crushed in the radial direction between the circular outer peripheral face 95 of the circular ring-shaped protruded part 91 of the upper case 12 and the circular inner peripheral face 68 b of the lower case 11 in a sandwiched state between the circular ring-shaped end face 96 a of the radial direction protruded part 96 and the circular ring-shaped end face 68 a of the circular ring-shaped stepped part 68. As a result, the leakage of liquid from the partitioned chamber 20 is prevented. In this embodiment, when the circular ring-shaped protruded part 91 of the upper case 12 is inserted into an inner side of the circular ring-shaped stepped part 68 of the lower case 11, the turning preventing protruded part 97 of the turning prevention mechanism 13 is fitted to the turning prevention recessed part 69 provided in the lower case 11 and thus the lower case 11 and the upper case 12 are prevented from being relatively turned to each other around the axial line “L”. Therefore, the O-ring 26 is prevented from being twisted in the circumferential direction in a state that the O-ring 26 is crushed in the radial direction and thus, when the pump chamber 25 is to be partitioned, the damage of the O-ring 26 is prevented. When the upper case 12 is superposed on the lower case 11 to form the pump chamber 25 (partitioned chamber 20) in a partitioned state, the lower end of the support shaft 24 penetrated through the bearing part 41 of the rotor 23 is inserted and fixed to the support shaft fixing recessed part 60 of the lower case 11 and the support shaft 24 and the center protruded part 80 are set to be in a coaxial state. Further, the rotor 23 is supported by the support shaft 24 in a rotatable state around the support shaft 24.
The tube shaped part 84 structuring the center protruded part 80 is provided with an outer peripheral face and an inner peripheral face which are formed in a tapered shape whose diameter is enlarged from a side of the bottom part 81 toward a side of an opening end 80 b along the axial line “L” direction. The outer peripheral face of the tube shaped part 84 is formed with three stator fixing protruding parts 85 which are protruded to outer sides in a radial direction from parts in the circumferential direction. The three stator fixing protruding parts 85 are provided with the same shape and are formed at an equal angular interval around the axial line “L”. Each of the stator fixing protruding parts 85 is formed so that its cross section perpendicular to the axial line “L” is a circular arc contour shape and is extended in the axial line “L” direction along the outer peripheral face of the center protruded part 80. Further, each of the stator fixing protruding parts 85 is provided with a tapered face whose protruding amount to an outer side in the radial direction and in the circumferential direction is increased from a side of the bottom part 81 toward a side of the opening end, in other words, from the upper side to the lower side. An upper end 85 a on the bottom part 81 side of each of the three stator fixing protruding parts 85 is reached to a protruding portion 80 a which protrudes in the center protruded part 80 upward from the opening of the stator accommodating room 83, and a lower end of each of the three stator fixing protruded parts 85 on the inner side ring-shaped part 90 side is reached downward with respect to a positioning part 88 described below.
Further, the outer peripheral face of the tube shaped part 84 of the center protruded part 80 is formed with a positioning part 88 so as to be abutted with the ring-shaped part 50 of the stator core 28 from the underside in the axial line “L” direction to position the stator core 28 in the axial line “L” direction. The positioning part 88 is a protruded part in a circular arc shape which is extended in a circumferential direction along the outer peripheral face of the tube shaped part 84 and is provided at three positions in the circumferential direction. An upper end face of the positioning part 88 which is abutted with the stator core 28 is a flat face which is perpendicular to the axial line “L”. The positioning part 88 and the stator fixing protruding part 85 are formed at a separated position in the circumferential direction and a gap space 88 a is provided between the positioning part 88 and the stator fixing protruded part 85 in the circumferential direction. Three pieces of a plate-shaped rib 98 are provided between the positioning part 88 and the cylindrical tube part 89 so as to extend in a radial direction and connect the positioning part 88 with the cylindrical tube part 89. Strength of the stator accommodating room 83 of the upper case 12 is assured by the ribs 98.
An inner peripheral face of the tube shaped part 84 of the center protruded part 80 is formed with three grooves 99 extending in the axial line “L” direction at corresponding positions to the respective stator fixing protruding parts 85 formed on the outer peripheral face of the tube shaped part 84. In other words, the inner peripheral face of the tube shaped part 84 of the center protruded part 80 is formed with three grooves 99 having the same shape at an equal angular interval around the axial line “L” of the support shaft 24. The cross-sectional shape perpendicular to the axial line “L” of each of the grooves 99 is semicircular and the groove 99 is extended in the axial line “L” direction along the inner peripheral face of the center protruded part 80. Further, a width in the circumferential direction of each of the grooves 99 is gradually increased from a side of the bottom part 81 toward a side of the opening end 80 b.
(Fixing Structure of Stator)
FIGS. 7( a) and 7(b) are partly enlarged views showing a stator accommodating room of an upper case and the like. FIG. 7( a) is a view showing a state that the stator 29 is not accommodated in the stator accommodating room and FIG. 7( b) is a view showing a state that the stator 29 is accommodated in the stator accommodating room. After the drive coil 27 is wound around each of the salient poles 51, the stator core 28 is fixed to the inside of the stator accommodating room 83 of the upper case 12. More specifically, in a state that the stator fixing protruding part 85 is fitted to the inner side recessed part 53 of the ring-shaped part 50 of the stator core 28, the stator 29 is inserted into the stator accommodating room 83 and, after that, the lower end portion 85 b of the stator fixing protruding part 85 (part on the opening end 80 b side of the center protruded part 80) is press-fitted to the inner side recessed part 53 of the ring-shaped part and thereby the stator 29 is fixed to the upper case 12. In this embodiment, a diameter on an inner side of the ring-shaped part 50 of the stator core 28 is larger than that of the tube shaped part 84 of the center protruded part 80 and thus, a gap space is structured between the inner side of the ring-shaped part 50 and the tube shaped part 84 except the portions of the stator fixing protruding parts 85. Further, a curvature of the inner side recessed part 53 of the ring-shaped part 50 of the stator core 28 is larger than that of the lower end portion 85 b of the stator fixing protruding part 85 and thus only a tip end part of the lower end portion 85 b of the stator fixing protruding part 85 is press-fitted to the bottom part of the inner side recessed part 53 of the ring-shaped part 50. In other words, a gap space is formed between the side faces in the circumferential direction of the lower end portion 85 b and the inner side recessed part 53.
In this embodiment, the upper end 85 a on the bottom part 81 side of the stator fixing protruding part 85 is reached to the protruding portion 80 a of the center protruded part 80 which is protruded upward from the opening of the stator accommodating room 83. Therefore, when the stator 29 is to be fitted to the stator accommodating room 83, the upper end 85 a of each of the stator fixing protruding parts 85 is easily fitted to the inner side recessed part 53 of the ring-shaped part 50 of the stator core 28. Further, the stator fixing protruding part 85 is formed in a tapered face which is widened toward the lower side and thus, when the stator 29 is inserted into the stator accommodating room 83, at first, the stator 29 is guided to a lower side by the stator fixing protruding parts 85. Then, the positioning part 88 is abutted with the ring-shaped part 50 of the stator core 28 from the underside to position the stator 29 in the axial line “L” direction. Further, the upper end faces of the positioning parts 88 are abutted with the stator core 28 and thus the attitude of the stator core 28 is determined. In this embodiment, the stator 29 is positioned and fixed in a state that the lower end portions 85 b of the stator fixing protruding parts 85 are press-fitted to the inner side recessed parts 53 of the ring-shaped part 50 of, for example, one piece of the plate-shaped core piece 52 structuring the stator core 28.
When the stator 29 is fixed to the inside of the stator accommodating room 83 of the upper case 12, the salient poles 51 of the stator core 28 around which the drive coil 27 is wound and the drive magnet 22 of the rotor 23 which is disposed in the partitioned chamber 20 are faced each other through the tube shaped part 84 of the upper case 12. In this state, a potting agent 16 is poured into the stator accommodating room 83. The potting agent 16 is flowed into a space structured between the inner side face of the ring-shaped part 50 and the tube shaped part 84 and thereby the stator 29 is covered by the potting agent 16.
In this embodiment, as shown in FIGS. 2( a) and 2(b), one or plural washers 43 are fitted between the upper end face of the bearing part 41 of the rotor 23 and the bottom part 81 of the protruded part and thereby the magnetic center position in the axial line “L” direction of the drive magnet 22 mounted on the rotor 23 is shifted to a lower side with respect to the magnetic center position in the axial line “L” direction of the stator core 28. As a result, the rotor 23 is urged upward by a magnetic attraction force acted between the stator core 28 and the drive magnet 22. In this embodiment, turning prevention parts 43 a in a semicircular shape are formed in each of the washers 43 so as to protrude to an outer side in the radial direction from its outer circumferential edge portion. Further, each of the turning prevention parts 43 a is fitted to each of the grooves 99 formed on the inner peripheral face of the center protruded part 80 and thereby the washer 43 is prevented from being turned around the axial line “L” when the rotor 23 is rotated. Further, as described above, one or two pieces of the washers 43 whose thickness is 0.2 mm and 0.3 mm are selectively used. In this case, when two turning prevention parts 43 a are provided in the washer 43 whose thickness is 0.2 mm and three turning prevention parts 43 a are provided in the washer 43 whose thickness is 0.3 mm, the washer 43 whose thickness is 0.2 mm and the washer 43 whose thickness is 0.3 mm are easily distinguished from each other.
(Operation and Effect)
According to this embodiment, the stator 29 is directly fixed to the upper case 12 (partition wall or first case) which partitions the stator 29 from the rotor 23. Therefore, positional accuracy of the stator 29 with respect to the upper case 12 (partition wall) can be enhanced. Further, different from a case that the stator core 28 is fixed to the upper case 12 in a state that the entire periphery in the circumferential direction of the center protruded part 80 is press-fitted to the ring-shaped part 50 of the stator 29, in this embodiment, the stator core 28 is fixed to the upper case 12 in a state that three stator fixing protruding parts 85 provided on the outer peripheral face of the tube shaped part 84 of the center protruded part 80 are press-fitted to the ring-shaped part 50 and thus a press-fitting margin between the upper case 12 and the stator core 28 is small. As a result, the stator core 28 is easily press-fitted when the stator core 28 is to be fixed to the upper case 12 and thus positional accuracy of the stator 29 with respect to the upper case 12 can be enhanced even when the stator 29 is press-fitted and fixed to the upper case 12. Therefore, a gap space between the stator core 28 of the stator 29 and the drive magnet 22 of the rotor 23 which face each other through the upper case 12 (partition wall) can be controlled with a high degree of accuracy.
Further, the inner peripheral face of the ring-shaped part 50 of the stator core 28 is formed with a plurality of inner side recessed parts 53 to which each of three stator fixing protruding parts 85 is capable of being press-fitted and each of the stator fixing protruding parts 85 is press-fitted to each of the inner side recessed parts 53. Therefore, the stator 29 (stator core 28) is positioned around the axial line “L”. Further, when the rotor 23 provided with the impeller 21 is rotated by the magnetic drive mechanism structured of the drive coil 27, the stator core 28 and the drive magnet 22, the stator 29 is prevented from being turned around the axial line “L” by the reaction force. In addition, in this embodiment, three stator fixing protruding parts 85 provided on the outer peripheral face of the center protruded part 80 are press-fitted to the inner side recessed parts 53 of the ring-shaped part 50 and thus stress at the time of press-fitting is easily released from each of the stator fixing protruding parts to the circumferential direction of the center protruded part 80. Therefore, deformation and damage of the upper case 12 can be prevented when the stator 29 is press-fitted and fixed.
In addition, three stator fixing protruding parts 85 are provided with the same shape as each other and three or more stator fixing protruding parts 85 may be formed at an equal angular interval. Therefore, when three stator fixing protruding parts 85 are press-fitted and fixed to the ring-shaped part 50, concentricity of the center protruded part 80 of the upper case 12 with the stator core 28 is improved. Accordingly, the positional accuracy of the stator 29 with respect to the upper case 12 is improved.
Further, in this embodiment, the stator 29 is covered by the potting agent 16 as a sealing agent which is poured into the stator accommodating room 83 and thus, even when a press-fitting margin between the upper case 12 and the stator core 28 is small, the stator 29 can be surely fixed to the upper case 12 by the potting agent 16.
In addition, in this embodiment, the inner peripheral face of the tube shaped part 84 of the center protruded part 80 is formed with the groove 99 at a position corresponding to each of the stator fixing protruding parts 85 formed on the outer peripheral face of the tube shaped part 84. Therefore, a thickness of the tube shaped part 84 of the center protruded part 80 can be set almost uniform over the entire periphery. As a result, shrinkage occurred in the center protruded part 80 when the upper case 12 is molded can be set uniform and thus the cylindricality of the center protruded part 80 is improved.
Further, in this embodiment, the positioning part 88 and the stator fixing protruding parts 85 are formed at separated positions in the circumferential direction and thus, even when the ring-shaped part 50 of the stator core 28 shaves the stator fixing protruding parts 85 made of resin at the time of press-fitting, shavings are not attached to the positioning part 88. Therefore, positioning in the axial line “L” direction of the stator 29 can be performed with a high degree of accuracy.
In addition, in this embodiment, the support shaft 24 rotatably supporting the rotor 23 is fixed to the center of the inner side face of the bottom part 81 (face on the partitioned chamber 20 side) of the center protruded part 80 to which the stator core 28 is fixed. Therefore, a relative positional accuracy of the rotor 23 supported by the support shaft 24 to the stator 29 is improved. Further, according to this structure, the support shaft 24 is fixed to the bottom part 81 of the center protruded part 80 and the stator core 28 is fixed to the opening end 80 b side of the center protruded part 80 and thus the fixed part of the stator 29 and the fixed part of the support shaft 24 are separated from each other in the axial line “L” direction. Therefore, even when the tube shaped part 84 of the center protruded part 80 may be deformed at the time of press-fitting and fixing of the stator 29, the fixing of the support shaft 24 is prevented from being unstable.

Other Embodiments

In the embodiment described above, each of the stator fixing protruding parts 85 and each of the inner side recessed parts 53 are provided with a circular arc contour in cross section and the tip end on the outer peripheral side of the stator fixing protruding part 85 is press-fitted to the inner side recessed part 53 and gap spaces are provided both sides in the circumferential direction. However, for example, it may be structured that one of the cross-sectional shapes of the stator fixing protruding part 85 and the inner side recessed part 53 is changed and both sides in the circumferential direction of the stator fixing protruding part 85 are press-fitted to the inner side recessed part 53 and a clearance is provided between the tip end on the outer side in the radial direction and the inner side recessed part 53. In this case, at the time of press-fitting, stress is restrained to occur the center protruded part 80 in the radial direction and thus deformation and damage of the upper case 12 can be prevented. In accordance with an embodiment of the present invention, no inner side recessed part 53 which is provided in the ring-shaped part 50 of the stator core 28 may be formed. Further, in a case that the entire periphery on the outer peripheral side of the stator fixing protruding part 85 is press-fitted to the inner side recessed part 53, positioning in the circumferential direction and the radial direction of the stator 29 are performed simultaneously. In addition, the cross sectional shapes of each of the stator fixing protruding part 85 and each of the inner side recessed part 53 are not limited to a semicircular shape and a triangular shape and a quadrangular shape may be used.
While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.
The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A pump device comprising:

a stator comprising:

a stator core having a ring-shaped part on a center side; and

a drive coil which is wound around the stator core;

a rotor provided with an impeller and a drive magnet which faces the stator through a predetermined distance on an outer peripheral side of the stator; and

a partition wall which is disposed between the stator and the rotor for separating a pump chamber in which the impeller is disposed from the stator;

wherein the partition wall is provided with a protruded part in a bottomed tube-like shape which is protruded on an inner side of the ring-shaped part;

wherein an outer peripheral face of a tube shaped part structuring the protruded part is formed with a plurality of protruding parts which protrude from parts in a circumferential direction to an outer side in a radial direction; and

wherein the stator core is fixed to the protruded part in a state that the plurality of the protruding parts is press-fitted to the ring-shaped part.

2. The pump device according to claim 1, wherein

an inner peripheral face of the ring-shaped part of the stator core is provided with a plurality of recessed parts to which each of the plurality of the protruding parts is capable of being press-fitted, and

the protruding parts are press-fitted to the recessed parts.

3. The pump device according to claim 2, wherein

both side portions in the circumferential direction of the protruding part are press-fitted to the recessed part, and

a clearance is provided between a tip end on an outer side in the radial direction of the protruding part and the recessed part.

4. The pump device according to claim 2, wherein the plurality of the protruding parts is formed in a same shape as each other and is formed at three or more positions at an equal angular interval.

5. The pump device according to claim 4, wherein

the protruding part is extended in an axial line direction along the outer peripheral face of the tube shaped part and is provided with a tapered face whose protruding amount to an outer side in the radial direction and to the circumferential direction is increased from a side of a bottom part of the protruded part in the bottomed tube-like shape toward a side of an opening end of the protruded part, and

a part of the protruding part on the side of the opening end is press-fitted to the ring-shaped part of the stator core.

6. The pump device according to claim 1, wherein

the partition wall is provided with a cylindrical tube part provided on an outer peripheral side of the protruded part and a circular ring-shaped part which connects an opening end of the protruded part with the cylindrical tube part,

the stator is accommodated in a circular ring-shaped recessed part for accommodating the stator which is formed of the protruded part, the cylindrical tube part and the circular ring-shaped part, and

the stator is covered by a sealing agent which is poured into the circular ring-shaped recessed part for accommodating the stator.

7. The pump device according to claim 6, wherein

the protruded part in the bottomed tube-like shape is provided with a protruding portion which protrudes in an axial line direction from an opening of the circular ring-shaped recessed part for accommodating the stator on a bottom part side of the protruded part, and

an end of the protruding part on the bottom part side of the protruded part is reached to the protruding portion.

8. The pump device according to claim 7, wherein

the partition wall is a resin molded product, and

an inner peripheral face of the tube shaped part structuring the protruded part is formed with a groove at a position corresponding to the protruding part formed on the outer peripheral face of the tube shaped part.

9. The pump device according to claim 8, wherein

a support shaft which rotatably supports the rotor is fixed to an inner side face of the bottom part of the protruded part,

the rotor is provided with a bearing part in a tube-like shape,

the bearing part is disposed on an inner side of the protruded part in a state that the support shaft is inserted into a center hole of the bearing part,

a washer for adjusting a position in the axial line direction of the rotor is fitted between the bottom part of the protruded part and the bearing part,

the washer is formed with a turning prevention part protruding to an outer side in the radial direction from an outer circumferential edge portion of the washer, and

the turning prevention part is fitted to the groove formed on the inner peripheral face of the tube shaped part.

10. The pump device according to claim 6, wherein a support shaft which rotatably supports the rotor is fixed to an inner side face of the bottom part of the protruded part.

11. The pump device according to claim 1, wherein

an outer peripheral face of the tube shaped part structuring the protruded part is provided with a positioning part which is abutted with the ring-shaped part of the stator core from a side of an opening end of the protruded part in the bottomed tube-like shape for positioning the stator in an axial line direction, and

the positioning part and the protruding part are formed at a separated position from each other in a circumferential direction.

12. The pump device according to claim 1, wherein the pump device comprises:

a first case which structures the partition wall and is provided with a circular ring-shaped protruded part on an inner side of an outer peripheral wall;

a second case which is provided with a circular ring-shaped stepped part into which the circular ring-shaped protruded part is coaxially inserted and which partitions the pump chamber on an inner peripheral side of the circular ring-shaped stepped part together with the first case; and

an O-ring which is attached on a circular outer peripheral face of the circular ring-shaped protruded part and is crushed between the circular outer peripheral face of the circular ring-shaped protruded part and a circular inner peripheral face of the circular ring-shaped stepped part in a direction perpendicular to an axial line of the circular ring-shaped protruded part.

13. The pump device according to claim 12, wherein

the first case is provided with a cylindrical tube part formed on an outer peripheral side of the protruded part and a circular ring-shaped part connecting an opening end of the protruded part with the cylindrical tube part,

14. The pump device according to claim 13, wherein

the second case comprises:

a bottom plate part;

a side wall part in a ring shape which is stood up from an outer peripheral side portion of the bottom plate part; and

a circular recessed part which is formed of the bottom plate part and the side wall part;

an inner peripheral face on an upper side of the side wall part is formed with the circular ring-shaped stepped part; and

a liquid flow passage is structured between the circular ring-shaped protruded part of the first case and the circular recessed part of the second case at a position on an inner side with respect to the circular ring-shaped stepped part.

15. A pump device comprising:

a stator comprising:

a stator core having a ring-shaped part on a center side; and

a drive coil which is wound around the stator core; and

a partition wall configured to separate a pump chamber from the stator;