U.S. patent application number 12/996693 was filed with the patent office on 2011-06-23 for operating machine, in particular a motor-driven pump with an axial motor arrangement.
This patent application is currently assigned to MATE S.A.S. DI FURLAN MASSIMO & C.. Invention is credited to Massimo Furlan.
Application Number | 20110150674 12/996693 |
Document ID | / |
Family ID | 40301998 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110150674 |
Kind Code |
A1 |
Furlan; Massimo |
June 23, 2011 |
Operating Machine, in Particular a Motor-Driven Pump with an Axial
Motor Arrangement
Abstract
The present invention refers to an operating machine, in
particular a motor-driven pump with an axial motor arrangement,
comprising a rotor assembly (18) and a stator assembly (7). The
rotor assembly (18) includes an impeller (4) and a permanent-magnet
rotor (5) firmly associated to the impeller (4). The stator
assembly (7) includes a single multipolar stator (8, 9, 10)
interacting with the rotor (5) to impart a rotary motion to the
impeller (4) along an axis (A) perpendicular to the rotor (5). The
rotor assembly (18) is rotatably supported by a flange (6) adapted
to separate the rotor assembly (18) from the stator assembly (7).
Guide means (16, 17) are provided between the rotor assembly (18)
and the flange (6) to guide the rotary motion of the impeller (4)
about the axis (A).
Inventors: |
Furlan; Massimo; (Conegliano
(Treviso), IT) |
Assignee: |
MATE S.A.S. DI FURLAN MASSIMO &
C.
Conegliano (Treviso)
IT
|
Family ID: |
40301998 |
Appl. No.: |
12/996693 |
Filed: |
June 24, 2009 |
PCT Filed: |
June 24, 2009 |
PCT NO: |
PCT/EP09/57875 |
371 Date: |
December 7, 2010 |
Current U.S.
Class: |
417/353 |
Current CPC
Class: |
F04D 29/047 20130101;
F04D 13/0666 20130101 |
Class at
Publication: |
417/353 |
International
Class: |
F04B 35/04 20060101
F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2008 |
IT |
PN2008A000051 |
Claims
1. Operating machine, in particular a motor-driven pump with an
axial motor arrangement, comprising a rotor assembly (18; 18A; 18B;
18C; 18D; 18E; 18F) and a stator assembly (7; 7A; 7B; 7C; 7D; 7E;
7F), said rotor assembly including an impeller (4; 4A; 4B; 4C; 4D;
4E; 4F) and a permanent-magnet rotor (5; 5A; 5B; 5C; 5D; 5E; 5F)
firmly associated to said impeller (4; 4A; 4B; 4C; 4D; 4E; 4F),
characterized in that said stator assembly (7; 7A; 7B; 7C; 7D; 7E;
7F) includes a single multipolar stator (8, 9, 10; 10A; 8B, 9B,
10B; 8C, 9C, 10C; 8D, 9D, 10D; 8E, 8'E, 9E, 10E, I CE; 8F, 9F, 10F)
interacting with said rotor (5; 5A; 5B; 5C; 5D; 5E; 5F) to impart a
rotary motion to said impeller (4; 4A; 4B; 4C; 4D; 4E; 4F) along an
axis (A) perpendicular to said rotor (5; 5A; 5B; 5C; 5D; 5E; 5F),
said rotor assembly (18; 18A; 18B; 18C; 18D; 18E; 18F) being
rotatably supported by a flange (6; 6A; 6B; 6C; 6D; 6E; 6F) adapted
to separate said rotor assembly (18; 18A; 18B; 18C; 18D; 18E; 18F)
from said stator assembly (7; 7A; 7B; 7C; 7D; 7E; 7F), guide means
(16, 17; 16A; 16B, 17B; 16C; 16D; 16E; 24F, 29F) being provided
between said rotor assembly (18; 18A; 18B; 18C; 18D; 18E; 18F) and
said flange (6; 6A; 6B; 6C; 6D; 6E; 6F) to guide the rotary motion
of said impeller (4; 4A; 4B; 4C; 4D; 4E; 4F) about said axis
(A).
2. Operating machine according to claim 1, wherein said guide means
(16, 17; 16A; 16B, 17B; 16C; 16D; 16E; 24F, 29F) extend
longitudinally along said axis (A) perpendicular to said rotor (5;
5A; 5B; 5C; 5D; 5E; 5F) leaving substantially free a central region
of said stator assembly (7; 7A; 7B; 7C; 7D; 7E; 7F).
3. Operating machine according to claim 2, wherein said guide means
(16, 17; 16A; 16B, 17B; 16C; 16D; 16E) extend along said axis (A)
protruding from said flange (6; 6A; 6B; 6C; 6D; 6E) and said rotor
assembly (18; 18A; 18B; 18C; 18D; 18E; 18F) towards said stator
assembly (7; 7A; 7B; 7C; 7D; 7E) substantially up to a region
defined by an upper portion of said multipolar stator (8, 9, 10;
10A; 8B, 9B, 10B; 8C, 9C, 10C; 8D, 9D, 10D; 8E, 8'E, 9E, 10E,
10'E).
4. Operating machine according to claim 3, wherein said guide means
(16, 17) comprise a circular groove (16) provided on said flange
(6) and adapted to engage a corresponding circular rim (17)
extending from said impeller (4) towards said flange (6).
5. Operating machine according to claim 4, wherein said circular
groove (16) is obtained in one piece with said flange (6) and said
circular rim (17) is obtained in one piece with said impeller
(4).
6. Operating machine according to claim 2, wherein said guide means
(24F, 29F) extend along said axis (A) from a central region of said
flange (6F) and said rotor assembly (18F) towards an upper portion
of said impeller (4F).
7. Operating machine according to claim 6, wherein said guide means
comprise a pin (24F) extending from a central region of said flange
(6F) and adapted to engage a corresponding recess (29F) in said
impeller (4F), said recess (29F) extending from a central base
portion of said impeller (4F) towards said upper portion of said
impeller (4F).
8. Operating machine according to claim 7, wherein antifriction
means (26F, 27F) are interposed between said pin (24F) and said
recess (29F).
9. Operating machine according to claim 7, wherein said pin (24F)
is obtained in one piece with said flange (6F).
10. Operating machine according to claim 1, wherein said impeller
(4) is formed by overmoulding onto said rotor (5).
11. Operating machine according to claim 1, wherein said said rotor
(5B) is firmly joined with said impeller (4B).
12. Operating machine according to claim 3, wherein said guide
means (16B, 17B) comprise a circular groove (16B) provided on said
flange (6B) and adapted to engage a corresponding circular rim
(17B) extending from said rotor (5B) towards said flange (6B).
13. Operating machine according to claim 1, wherein said rotor (5;
5A; 5B; 5C; 5D; 5E; 5F) is axially magnetized.
14. Operating machine according to claim 1, wherein said multipolar
stator comprises a plurality of magnetic poles (8; 8B; 8C; 8F)
connected to a yoke (9; 9B; 9C; 9F) and a plurality of stator coils
(10; 1 OB; 10C; 10F), each stator coil of said plurality of stator
coils (10; 10B; 10C; 10F) being wound round a respective magnetic
pole of said plurality of magnetic poles (8; 8B; 8C; 8F).
15. Operating machine according to claim 1, wherein said multipolar
stator comprises a plurality of stator coils (10A), each stator
coil of said plurality of stator coils (10A) being wound to form a
respective magnetic pole.
16. Operating machine according to claim 1, wherein said multipolar
stator comprises at least one stator coil (10D; 10E, 10'E) at least
partially enclosed by a plurality of magnetic poles (8D; 8E, 8'E)
that close up in an alternate sequence on the upper side of said at
least one stator coil (10D; 10E, 10'E) to form a respective
plurality of alternate patterns of north and south poles.
17. Operating machine according to claim 16, wherein said
multipolar stator comprises at least a first stator coil (10E) and
a second stator coil (10'E), said first stator coil (10E) and
second stator coil (10'E) being at least partially enclosed by a
first plurality of magnetic poles (8E) and a second plurality of
magnetic poles (8'E), respectively, said first stator coil (10E)
and said second stator coil (10'E) and, respectively, said first
plurality of magnetic poles (8E) and said second plurality of
magnetic poles (8'E) being concentrically arranged relative to each
other.
18. Operating machine according to claim 1, wherein said rotor
assembly (18; 18A; 18B; 18C; 18D; 18E; 18F) is contained in a
diffuser (1 ;1A; 1 B; 1 C; 1 D; 1 E; 1 F) provided with an inflow
aperture (2; 2A; 2B; 2C; 2D; 2E; 2F) and at least one outflow
aperture (3; 3A; 3B; 3C; 3D; 3E; 3F), said diffuser (1 ; 1A; 1 B; 1
C; 1 D; 1 E; 1 F) being sealingly connected to said flange (6; 6A;
6B; 6C; 6D; 6E; 6F).
19. Operating machine according to claim 18, wherein at least one
heating element (20) is associable to said diffuser (1 C).
20. Operating machine according to claim 19, wherein said heating
element (20) is wound either inside or outside on said diffuser (1
C) or incorporated therein.
Description
[0001] The present invention refers to an operating machine, in
particular a motor-driven pump with an axial motor arrangement,
which comprises a chamber where there is arranged a concentric
impeller rotating about an axis; the concentric impeller is
provided with vanes adapted to impart a kinetic impulse to a
working fluid--either in a liquid or a gaseous form--at the pump
outlet.
[0002] When designing operating machines of the above-noted kind
for use in a variety of industry sectors, such as for instance in
the sector of home appliances including clothes washing machines
and dishwashing machines, a major factor that needs to be taken
into due consideration is the volume occupied by the machine: this
is a parameter which has to be kept as low as possible, and even
progressively reduced, so as to render the machine more and more
integrated in the structure which has to incorporate it. This has
the aim, on the one hand, to achieve a larger free volume available
inside said structure and, on the other hand, to allow the
operating machine to be used in applications where available
built-in space for accommodation of such machine gives rise to
serious dimensional constraints.
[0003] Another particularly critical aspect to be considered when
designing operating machines of the above-noted kind relates to the
reliability of the hermetic sealing of the rotating members; in
fact, the sealing gaskets used for the rotor assembly are generally
subject to frictional wear, which causes the same gaskets to
undergo rapid deterioration and, as a result, a corresponding decay
in the sealing properties thereof; this gives rise to a possibility
for the machine to start malfunctioning due to leakages, seepages,
pressure drops or losses, and the like.
[0004] US 2005/0147512 discloses a rotary pump for use in the
medical field, in particular in connection with applications in the
cardiovascular sector as a means to assist in the pumping function
of the heart of a patient. This pump includes an impeller supported
by magnetic bearings of an axial type, which consist of a magnet
incorporated in the impeller and two mutually opposed stator
windings. The magnetic field created by said magnet and said
windings causes the impeller to, so to say, float within the body
containing it.
[0005] Although being particularly compact in volume, even
considering the applications it is intended for, the constructive
concepts at the basis of a pump of this kind are such as to enable
to achieve output power levels certainly suitable to an application
in the medical field, but totally inadequate to applications in
industry products such as home appliances and the like.
[0006] Moreover, the presence of electromagnetic bearings implies a
need to constantly check and control in a very accurate manner the
power supply to the stator windings so as to keep the impeller duly
floating between the two windings. In fact, even a quite slight
variation in the potential between such two windings would cause
the impeller, which incorporates the magnet, to be attracted
towards either one or the other winding, thereby possibly impairing
the correct operation of the pump.
[0007] Another drawback lies in the fact that the inlet pipe of the
pump extends through a stator winding, so that the diameter of such
pipe is subject to strict dimensional constraints. As a result, the
actual flow rate of the working fluid is limited by such
dimensional constraints, and this is the reason why the pump is
practically suited to applications involving a low flow-rate of
fluid, as this is in fact the case in the medical field.
[0008] FR 2734605 discloses an electric water-pump for domestic
appliances which includes an electric motor which drives a turbine
of the electric pump. The electric motor is a permanent-magnet type
motor and the turbine is associated directly with the rotor in such
a way that a compact structure is achieved, in which the usual
rotor of the motor is part of the turbine, the latter enclosing the
electromotor rotor.
[0009] DE 19646617 discloses a pump which has a pump wheel rotor in
a pump chamber and a pole system in a pole chamber with motor
windings. Both chambers are hermetically sealed each other. The
pole chamber is mounted in a heat conducting metal housing and the
pole system is held radially, axially and rotationally fixed with
the motor windings, pole cores and a short circuit ring. The motor
windings are connected via cables to a circuit board mounted in an
auxiliary chamber in contact with the metal housing wall.
[0010] Both these prior art embodiments feature a rotor and a
turbine, or pump wheel, rotating about an axis defined by a pin
perpendicularly extending from a central portion of the stator
assembly, or pole chamber, into a housing in the turbine or pump
wheel. The pin, acting as a guiding and controlling means of the
rotary motion of the rotor and the turbine in respect of the
stator, has a lower portion housed in a deep recess of a flange
hermetically separating the rotor from the stator and an upper
portion housed in a recess of the turbine with the interposition of
a cylindrical bearing. Such a construction implies that, in case of
a small misalignment of the pin in respect to the rotational
perpendicular axis, vibrations of a significant amount can occur in
the rotating assembly, i.e. the rotor and the turbine, due to the
high extension of the pin.
[0011] Further, for the same reason, few or no space is left in the
stator, or pole chamber, for arranging electronic control circuits
or devices, due to the presence of the lower portion of the pin and
the related housing in the flange; this drawback is particularly
felt when the pump has to be extremely compact, such as for
instance its use in domestic appliances like dishwashers or washing
machines.
[0012] It is therefore a main object of the present invention to
provide a pump of the afore-noted kind, which is effective in doing
away with the drawbacks and limitations of prior-art pumps as
stated above.
[0013] Within this general aim, it is a purpose of the present
invention to provide an operating machine, in particular a
motor-driven pump with an axial motor arrangement, wherein the
dimensions, in particular the axial dimension, are considerably
reduced while keeping the capability to supply power output levels
suitable to industry applications.
[0014] Another purpose of the present invention is to provide an
operating machine wherein any sealing members between fluid and
rotating parts, in particular between the fluid and the motor, can
be eliminated while anyway ensuring the required hermetic sealing
of the same rotating parts.
[0015] A further purpose of the present invention is to provide an
operating machine wherein the hermetic sealing between the rotating
parts and the working fluid is ensured to stay unaltered and fully
reliable in the long term, so that the causes of frictional wear
are prevented or significantly reduced.
[0016] Yet another purpose of the present invention is to simplify
the control of power supply to the electric motor while at the same
time reliably ensuring correct operation of the machine.
[0017] A further purpose is to provide an operating machine
extremely compact and able to house inside the stator compartment
the required electronic control circuits and devices.
[0018] Another purpose is to provide an operating machine wherein
vibrations are prevented or considerably reduced.
[0019] Another, equally important purpose of the present invention
is to provide an operating machine of the above-noted kind at fully
competitive costs with the use of readily available techniques,
tools and machinery.
[0020] According to the present invention, these aims, along with
further ones that shall become apparent from the following
disclosure, are reached in an operating machine, in particular a
motor-driven pump with an axial motor arrangement, as defined in
claim 1.
[0021] Further characteristics of the operating machine according
to the present invention are defined in the dependent claims.
[0022] Features and advantages of the present invention will anyway
be more readily understood from the description of a preferred,
although not sole embodiment that is given below by way of
non-limiting example with reference to the accompanying drawings,
in which:
[0023] FIG. 1 is a perspective view of an operating machine
according to the present invention;
[0024] FIG. 2 is an exploded perspective view of main parts forming
the operating machine shown in FIG. 1;
[0025] FIG. 3 is a cross-sectional view along a diametrical plane
of a component part of the operating machine shown in FIG. 1;
[0026] FIG. 4 is a plan view of the operating machine shown in FIG.
1;
[0027] FIG. 5 is a cross-sectional view of the operating machine
shown in FIG. 4 taken along plane V-V;
[0028] FIG. 6 is an exploded perspective view of a second
embodiment of an operating machine according to the present
invention;
[0029] FIGS. 7 and 8 are views of a third embodiment of an
operating machine according to the present invention;
[0030] FIGS. 9 and 10 are views of a fourth embodiment of an
operating machine according to the present invention;
[0031] FIG. 11 is a view of a fifth embodiment of an operating
machine according to the present invention;
[0032] FIG. 12 is a view of a sixth embodiment of an operating
machine according to the present invention;
[0033] FIG. 13 is a view of a seventh embodiment of an operating
machine according to the present invention;
[0034] FIG. 14 is an exploded perspective view of some component
parts of the embodiment of FIG. 13;
[0035] FIG. 15 is a cross-sectional view of the component parts
shown in FIG. 14 taken along a diametral plane.
[0036] With reference to above-listed Figures, the inventive
operating machine, such as a motor-driven pump with an axial motor
arrangement, comprises a diffuser 1 with an inflow 2 and at least
one outflow 3 for a working fluid, a rotor assembly 18, which
essentially comprises an impeller 4 and an axially magnetized
permanent-magnet rotor 5 that is associated in a firmly joined
manner to the impeller 4; a flange 6 separates the rotor assembly
18 from a stator assembly 7 consisting essentially of a multipolar
stator that comprises a plurality of magnetic poles 8 connected to
a yoke 9, as well as a plurality of stator coils 10, each one of
which being wound round a respective magnetic pole 8. Each such
stator coil 10 is energized via an electrical connection 11
connected to a base plate 12; the stator 7 is housed within a body
13 provided with connectors 14 connected, on one side thereof, to
the base plate 12; on the opposite side, the connectors 14 are
adapted to be connected--with the aid of means known in the art--to
both the power-supply line and the control signals.
[0037] Advantageously an electronic circuit 15, properly arranged
on the base plate 12, can be provided for controlling the power
supply to the stator assembly 7.
[0038] Appropriate guide means for guiding the rotary motion of the
impeller 4 along an axis A extending perpendicularly to the rotor 5
are provided between the impeller 4 and the flange 6; the guide
means are arranged so as to leave substantially free a central
region of the stator assembly 7; in such a way, the electronic
circuit 15, or any other devices that may be required for the
functioning of the operating machine, can be easily arranged on the
base plate 12 and housed in the stator assembly 7 in order to
achieve an extremely compact structure of the operating
machine.
[0039] In the embodiment of FIGS. 1 to 5, as well as in the
subsequent embodiments of FIGS. 6, 7-8, 9-10, 11 and 12 which will
be disclosed more in detail below, the guide means extend
downwardly along the axis A protruding from the flange 6 and the
rotor assembly 18 toward the stator assembly 7 substantially up to
a region defined by a top portion of the multipolar stator, in
particular a top portion of the magnetic poles 8.
[0040] Such guide means may consist of a circular groove 16, which
may for instance be provided on the flange 6, and which is capable
of engaging a corresponding circular rim provided on the impeller 4
or the rotor 5, as it shall be described in more detail below. It
shall be of course understood that a reversed arrangement of the
described groove-rim engagement has to be considered fully
equivalent to the purposes of the present invention.
[0041] According to a preferred embodiment, which is illustrated in
FIG. 3, the rotor assembly 18 is formed by overmoulding the
impeller 4 onto the rotor 5, whereby a thin disk 19 resting on the
flange 6 and adapted to support the rotor 5 is obtained on the
impeller 4; a circular rim 17 protruding from the disk 19 extends
towards the groove 16 on the flange 6.
[0042] Advantageously, the circular groove 16 is obtained in one
piece with the flange 6 and the circular rim is obtained in one
piece with the impeller 4.
[0043] It shall be appreciated that different embodiments of the
guide means may of course be contemplated without departing from
the scope of the present invention as defined in claim 1.
[0044] Advantageously, the rotor 5 may be formed of a portion of
permanent magnets 21 and a portion made of ferromagnetic material
22, so as to improve the efficiency or increase the power output of
the operating machine.
[0045] The operating machine according to the present invention
operates as follows: once that the stator coils 10 are electrically
energized via the connectors 14 and the related electrical
connections 11, the multipolar stator 7 imparts a rotary motion to
the permanent-magnet rotor 5 which, in turn, causes the impeller 4
to rotate, being the rotor 5 firmly joined to the impeller 4.
[0046] The rotor 5 is driven into rotation and attracted by the
electromagnetic force exerted by the stator 7, so that the rotor
assembly 18, which comprises the impeller 4 and the rotor 5, is
caused to rotate while slidably resting on the flange 6; the rotary
motion of the rotor assembly 18 is guided by the guide means
situated between the same rotor assembly 18 and the flange 6. In
this particular case, this is achieved by the engagement between
the groove 16 in the flange 6 and the circular rim 17 of the
impeller 4, as described above.
[0047] Fully apparent from the above description is therefore the
ability of the present invention to effectively reach the aims and
advantages cited afore, by in fact providing an operating machine,
in particular a motor-driven pump with an axial motor arrangement,
which is effective in doing away with the drawbacks of
prior-art.
[0048] In the first place, the above-cited operating machine
according to the present invention allows to sensibly reduce the
overall dimensions, in particular the overall axial dimensions of
the machine, thanks to the fact that the rotor 5 is incorporated in
the impeller 4, as well as to the fact that there is no need to
provide any rotating sealing member between the working fluid and
the rotor assembly 18. In fact, the rotary motion of the rotor 5
driven by the electromagnetic field created by the stator assembly
7 causes the transmission of such rotary motion to the impeller 4,
thereby allowing to eliminate the conventional motor shaft used for
motion transmission to the impeller. Therefore the flange 6 can be
made as a solid piece without any aperture in it, since no aperture
is in fact required any longer to allow a motor shaft passing
therethrough, as this is usually needed in the prior art and, as a
consequence, no rotary sealing means are longer required to prevent
working fluid from possibly seeping therethrough.
[0049] The elimination of such rotary sealing means makes it
furthermore possible to prevent another primary cause of
malfunctioning of the machine due to the wear and tear of such
sealing members In fact, hermetic sealing is solely required at the
joint between the flange 6 and the diffuser 1 and, therefore,
between parts that do not move relative to each other, whereby it
is possible to use solely static sealing members which are not
subject to frictional wear. Optimum fluid-tightness properties of
the machine are in this way reliably ensured in the long-term.
[0050] In addition, the sliding-type support of the rotor assembly
18 on the flange 6 introduces a considerable simplification in the
manner in which the power supply to the stator assembly 7 can be
controlled; in fact, the attraction force of the magnetic field is
unidirectional and oriented in a direction in which it attracts the
rotor assembly 18 towards the flange 6.
[0051] A further advantage lies in the possibility to incorporate
the electrical connections and even a possibly provided electronic
control circuit 15 within the stator assembly 7 thanks to an
improved distribution of internal volumes which allows to save a
considerable amount of space in the final application.
[0052] It shall be appreciated that the present invention may of
course be the subject of a number of further embodiments and
modifications without departing from the scope of the invention as
defined in claim 1.
[0053] By way of example, a second embodiment of the operating
machine according to the present invention is illustrated in FIG.
6, wherein the stator assembly 7A solely comprises a plurality of
stator coils 10A, each one of which being wound so as to form a
respective magnetic pole. Such an embodiment is particularly
suitable in the case of operating machines in which the power
rating required for the specific industrial application is not
high, so that the magnetic field created by the sole coils 10A
proves adequate to ensure such power level.
[0054] In a third embodiment of the operating machine according to
the present invention, as illustrated in FIGS. 7 and 8, the rotor
assembly 18B comprises a rotor 5B that is firmly joined on its
lower side to the impeller 4B by methods known in the art, such as
by welding, bonding or the like; a circular rim 17B which protrudes
on the lower side of the rotor 5B forms, together with the groove
16B in the flange 6B, the guide means for the rotary motion of the
impeller 4B.
[0055] FIGS. 9 and 10 illustrate a fourth embodiment, in which a
heating element 20, such as for instance an electric resistance
heater, an induction heater or the like, is added to an operating
machine provided as described above. The heating element 20 is
wound--either inside or outside--round the diffuser 1C, or it may
even be incorporated therein, and is advantageously energized via
the electrical connection 11C that ensures the power supply to the
coils 100 and/or the possibly provided electronic control circuit
15C. Even the appropriately provided cut-off devices and the
sensors used to control and protect the heating element 20 against
overheating may be energized via the same electrical connection 11C
and/or the possibly provided electronic control circuit 15C.
[0056] A protective cover 23 is preferably provided to both protect
and thermally insulate the heating element 20 from the outside
environment.
[0057] Incorporating a heating element 20 in an operating machine
made and embodied as described above makes it possible to transfer
heat from the rotor to the working fluid so as to increase the
thermodynamic efficiency of the system whenever the working fluid
is required to be heated. In addition, the power rating of the same
heating element can be reduced by taking advantage of using a part
of the heat generated by the rotor.
[0058] A fifth embodiment of an operating machine according to the
present invention is illustrated in FIG. 11, wherein the multipolar
stator in this case comprises a single coil 10D and the flux is
conveyed via a plurality of magnetic poles 8D, preferably made of a
ferromagnetic material, which close up in an alternate sequence on
the upper side of the coil 10D so as to form an alternate pattern
of north and south poles. Advantageously, in a particularly
cost-effective configuration thereof, the poles may be provided in
the form of appropriately cut and bent sheet-metal.
[0059] With this further embodiment, particularly suitable for
applications requiring a reduced power rating, such as in the case
of, for example, drain pumps, low-cost air circulation pumps for
ovens, cookers or stoves, circulation pumps for small water
treatment plants, or the like, a further and significant reduction
in manufacturing costs is obtained, thanks to an extremely
simplified construction of the related component parts, while
anyway ensuring an effective and reliable separation of the working
fluid from the dry portion of the machine without any use of rotary
sealing means.
[0060] A sixth embodiment--similar to the previous embodiment--of
an operating machine according to the present invention is
illustrated in FIG. 12, wherein two coils 10E, 10'E are provided,
which are arranged concentrically relative to each other and are
partially enclosed by a first and a second plurality of magnetic
poles 8E, 8'E, respectively. Again, these magnetic poles close up
in an alternate sequence on the upper sides of the respective coils
10E, 10'E so as to form respective alternate patterns of north and
south poles.
[0061] A seventh embodiment, as shown in FIGS. 13 to 15, comprises
a diffuser 1F with an inflow 2F and at least one outflow 3F for a
working fluid, a rotor assembly 18F, which essentially comprises an
impeller 4F and an axially magnetized permanent-magnet rotor 5F
that is associated in a firmly joined manner to the impeller 4F,
preferably overmoulded or permanently attached by, for instance,
welding, bonding or the like; a flange 6F separates the rotor
assembly 18F from a stator assembly 7F consisting essentially of a
multipolar stator that comprises a plurality of magnetic poles 8F
connected to a yoke 9F, as well as a plurality of stator coils 10F,
each one of which being wound round a respective magnetic pole 8F.
Each such stator coil 10F is energized via an electrical connection
11F connected to a base plate 12F; the stator 7F is housed within a
body, advantageously formed by a first half body 13F and a second
half body 13'F, provided with connectors (not shown) suitable to be
connected, on one side, to the base plate 12F and, on the opposite
side, to both the power-supply line and the control signals.
[0062] Advantageously an electronic control circuit or an
electronic control board, properly arranged on the base plate 12F,
can be provided for controlling the power supply to the stator
assembly 7F, as exemplified in the previous embodiments.
[0063] Appropriate guide means for guiding the rotary motion of the
impeller 4F along the axis A extending perpendicularly to the rotor
5F are provided between the impeller 4F and the flange 6F; the
guide means are arranged so as to leave substantially free a
central region of the stator assembly 7F; in such a way, an
electronic circuit, or any other devices that may be required for
the functioning of the operating machine, can be easily arranged on
the base plate 12F and housed in the stator assembly 7F in order to
achieve an extremely compact structure of the operating machine, as
previously described.
[0064] In the embodiment of FIGS. 13 to 15 the guide means extend
upwardly along the axis A from a central region of the flange 6F
and the rotor assembly 18F towards an upper portion of the impeller
4F.
[0065] Such guide means comprise a pin 24F which extends upwardly
from a central region of the flange 6F and it is adapted to engage
with a corresponding recess 29F in the impeller 4F which extends
from a central base portion towards an upper portion of the
impeller 4F.
[0066] Advantageously, the pin 29F is obtained in one piece with
the flange 6.
[0067] In order to reduce friction between the rotor assembly 18F
and the flange 6F, antifriction means are advantageously provided;
such antifriction means may comprise axial antifriction means, for
instance constituted by a bush 26F made of an antifriction
material, interposed between the pin 24F and the recess 29F in the
impeller 4F, and radial antifriction means constituted, for
instance, by a washer 27F, preferably also made of an antifriction
material, housed in a recessed seat 25F of the flange 6F; the
washer 27F may be directly in contact with the bush 26F, as shown
in FIG. 15, or with a central portion of the base of the impeller
4F.
[0068] It shall be appreciated that the materials used, as well as
the shape and the dimensions of the various parts, may of course
each time be selected so as to more appropriately meet the
particular requirements or suit the particular application.
* * * * *