U.S. patent application number 11/915353 was filed with the patent office on 2011-03-31 for electric motor ii.
This patent application is currently assigned to LINDENMAIER AG. Invention is credited to Thomas Bischof, Holger Godeke, Ralf Heber, Oliver Kampfer, Rudolf Loffler, Sandra Stehmer.
Application Number | 20110076167 11/915353 |
Document ID | / |
Family ID | 38421585 |
Filed Date | 2011-03-31 |
United States Patent
Application |
20110076167 |
Kind Code |
A1 |
Godeke; Holger ; et
al. |
March 31, 2011 |
Electric Motor II
Abstract
An electric motor conveys media and includes a stator, a rotor
with a rotor magnet, and a media throughput opening between the
stator and rotor. An operationally reliable delivery of media at
low cost and with low maintenance is achieved with the electric
motor.
Inventors: |
Godeke; Holger; (Achstetten,
DE) ; Loffler; Rudolf; (Unteressendorf, DE) ;
Heber; Ralf; (Erbach-Ersingen, DE) ; Bischof;
Thomas; (Illerbeuren, DE) ; Stehmer; Sandra;
(Wurzach, DE) ; Kampfer; Oliver; (Mainz,
DE) |
Assignee: |
LINDENMAIER AG
Laupheim
DE
|
Family ID: |
38421585 |
Appl. No.: |
11/915353 |
Filed: |
October 25, 2007 |
PCT Filed: |
October 25, 2007 |
PCT NO: |
PCT/EP2007/009445 |
371 Date: |
March 24, 2010 |
Current U.S.
Class: |
417/410.1 ;
310/60A |
Current CPC
Class: |
Y02T 10/12 20130101;
F05B 2220/40 20130101; F05D 2220/768 20130101; F01D 5/025 20130101;
H02K 5/128 20130101; H02K 7/14 20130101; F02B 39/10 20130101; F04D
13/0646 20130101; F05D 2220/40 20130101; F05D 2220/7642 20130101;
F04D 25/024 20130101; H02K 9/06 20130101; F05B 2220/70642 20130101;
F01N 13/107 20130101; F05B 2270/304 20130101; F05D 2220/76
20130101; F02B 37/10 20130101; F05B 2220/7068 20130101; H02K 7/1823
20130101; F05B 2220/706 20130101; Y02E 20/14 20130101; Y02E 10/30
20130101; F03B 17/061 20130101; Y02E 10/20 20130101; F02B 37/025
20130101; F04D 25/0606 20130101; F01D 25/16 20130101; F05D 2270/304
20130101 |
Class at
Publication: |
417/410.1 ;
310/60.A |
International
Class: |
F04B 35/04 20060101
F04B035/04; H02K 9/00 20060101 H02K009/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2007 |
EP |
07090100.4 |
Jun 20, 2007 |
EP |
07075496.5 |
Jul 1, 2007 |
EP |
07075661.4 |
Claims
1-32. (canceled)
33. An electric motor for delivering media, comprising: a stator; a
rotor including a rotor magnet; and a media passage opening located
between the stator and the rotor, wherein, in at least one cross
section of the electric motor, a ratio of a first cross-sectional
area of an inlet opening to a second cross-sectional area of the
rotor magnet is between 0.5 and 100.
34. A motor according to claim 33, wherein the ratio is between 0.8
and 50.
35. A motor according to claim 33, wherein the ratio is between 2
and 20.
36. A motor according to claim 33, wherein the rotor magnet has a
remanence between 0.3 Teslas and 0.8 Teslas.
37. A motor according to claim 33, wherein the rotor magnet has a
remanence larger than 0.8 Teslas.
38. A motor according to claim 33, wherein the rotor magnet has a
remanence larger than 1.2 Teslas.
39. A motor according to claim 33, wherein a flux density in the
media passage opening is between 0.05 Teslas and 0.5 Teslas.
40. A motor according to claim 33, wherein a flux density in the
media passage opening is more than 0.5 Teslas.
41. A motor according to claim 33, wherein the rotor magnet is of
one piece.
42. A motor according to claim 33, wherein the rotor magnet has is
a substantially cylindrical shape.
43. A motor according to claim 33, wherein the rotor magnet is a
solid cylinder.
44. A motor according to claim 33, wherein the rotor magnet has a
central bore for fastening.
45. A motor according to claim 33, wherein a smallest diameter of
the stator is 8.01- to 15-times as large as a largest outer
diameter of the rotor.
46. A motor according to claim 33, wherein a smallest diameter of
the stator is 8.01- to 12-times as large as a largest outer
diameter of the rotor.
47. A motor according to claim 33, wherein a smallest inner
diameter of the stator is 1.1- to 1.49-times as large as a largest
outer diameter of the rotor.
48. A motor according to claim 33, wherein a smallest inner
diameter of the stator is 1.25- to 1.49-times as large as a largest
outer diameter of the rotor.
49. A motor according to claim 33, wherein, in at least one cross
section, the ratio is between 2 and 100.
50. A motor according to claim 33, wherein, in at least one cross
section, the ratio is between 10 and 50.
51. A motor according to claim 33, wherein the at least one cross
section runs through one of magnetically effective sections and
electrically effective sections of the stator.
52. A motor according to claim 33, wherein the at least one cross
section lies perpendicular to an axis of the rotor.
53. A motor according to claim 33, wherein a smallest inner
diameter of the stator is between 1.5- and 8-times as large as a
largest outer diameter of the rotor magnet.
54. A motor according to claim 33, wherein the motor is a permanent
magnet synchronous motor.
55. A motor according to claim 33, wherein the rotor magnet has at
least one of a remanence greater than 0.8 Teslas and a high energy
density greater than 100 kJ/m3.
56. A motor according to claim 33, wherein the rotor magnet
consists of rare earth materials.
57. A motor according to claim 33, wherein the rotor magnet
consists of one of NdFeB and SmCo.
58. A motor according to claim 33, wherein the rotor magnet is
surrounded by a sheathing.
59. A motor according to claim 59, wherein the sheathing has a
substantially cylindrical shape.
60. A motor according to claim 33, wherein the stator is a part of
an inner wall of a surrounding housing.
61. A motor according to claim 33, wherein the stator, as an
insert, is applied into a corresponding opening of a surrounding
housing.
62. A motor according to claim 33, wherein the media passage
opening is free of struts between the rotor and the stator.
63. A motor according to claim 33, wherein the stator has a
substantially hollow-cylindrical shape.
64. A motor according to claim 33, wherein the rotor magnet is
prepared for integration into a shaft and onto a common shaft with
one of a media impeller and a media conveyor worm.
65. A motor according to claim 33, wherein the rotor magnet is one
of partially integrated and substantially completely integrated
into one of a media impeller and a media conveyor worm.
66. A motor according to claim 33, wherein one of the media
impeller and the media conveyor worm is composed of a material
which is one of a magnetically non-conductive material and a
substantially a magnetically non-conductive material.
67. A motor according to claim 33, wherein one of the media
impeller and the media conveyor worm is composed of a material
which includes one of a reinforced plastic and a non-reinforced
plastic.
68. A motor according to claim 33, wherein the stator includes with
a shielding towards the inside.
69. A motor according to claim 68, wherein the shielding has the
form of one of a tube and a flexible tubing.
70. A motor according to claim 68, wherein the shielding is
composed of an electrically non-conductive material and a
magnetically non-conductive material.
71. A motor according to claim 33, wherein the rotor comprises a
rotor shaft, the rotor shaft being mounted in one of a simple
manner and a multiple manner over its length.
72. A motor according to claim 40, wherein the rotor shaft is
substantially mounted on a first side and substantially freely
projects on a second side.
73. A motor according to claim 33, wherein at least one of the
rotor and the rotor magnet is integrated into a shaft to be driven
by the motor.
74. A motor according to claim 33, wherein the rotor shaft is
mounted one of a non-lubricated manner and a lubricated manner by a
delivery medium.
75. A motor according to claim 33, wherein an axial centre of the
stator and an axial centre of the rotor are displaced in an axial
direction.
76. A motor according to claim 33, wherein an axial centre of the
stator and an axial centre of the rotor are displaced in an axial
direction between 0.1 and 0.2 of a largest axial extension of the
rotor magnet.
77. The use of an electric motor which includes a stator; a rotor
including a rotor magnet; and a media passage opening located
between the stator and the rotor, wherein, in at least one cross
section of the electric motor, a ratio of a first cross-sectional
area of an inlet opening to a second cross-sectional area of the
rotor magnet is between 0.5 and 100, and wherein the motor being
used in an electrically aided turbocharger with a freely projecting
electric rotor, for a transport of explosive gases, dusts, vapours,
sticking substances, pastes, liquids such as water or oil;
decomposing products, such as foodstuffs; in ventilation devices,
in pumps, in particular in pumps for aggressive media, such as salt
water, chemical solutions (in particular in the orthodontic field);
in disinfectable or sterilisable pumps, canned pumps (medium
transport in the axial direction), metering pumps, micro-pumps,
disposable pumps, multi-stage pump systems; for use in turbines,
generators, conveyor worms for example for granular media, fluids
or pastes; in gas-, water- and steam turbines; in devices for
measuring the media flow via a generator voltage.
Description
[0001] The present invention relates to an electric motor according
to the preamble of patent claim 1.
[0002] Electric motors are known in various embodiments. For
example, motors are known for conducting media, which comprise a
rotor and a stator located around this, wherein the rotor is
connected to a media impeller and by way of this may regulate the
flow of media.
[0003] With motors leading media, one strives for a simple
construction as well as highest possible integration into an
existing housing system. Here, apart from observing the desired
simplicity for reasons of repair, one should also take note of the
sealedness, in particular with regard to the electrically
conducting parts of the electric motor.
[0004] It is therefore the object of the invention to provide an
electric motor which has an extremely simple construction, has a
good sealedness with regard to the media to be delivered, and
despite this has a high performance and is energy-efficient.
[0005] This object is achieved by an electric motor according to
claim 1. Here, it is the case of an electric motor for delivering
media, wherein this comprises a stator, a rotor with a rotor
magnet, as well as a media passage opening between the stator and
rotor. In at least one cross section, the ratio of the
cross-sectional area of the inlet opening to the cross-sectional
area of the rotor magnet (expressed with regard to a formula:
V.sub.QE=A.sub.inlet opening/A.sub.rotor magnet) is between 0.5 and
100, preferably between 0.8 and 50, particularly preferably between
2 and 20.
[0006] The primary work power of the media gap motor is the
delivery of media through the gap between the rotor and stator, or
as a generator, the drive by the delivery medium in the media
gap.
[0007] "Cross-sectional area of the inlet opening" is to be
understood as the actual open cross section in which air or a fluid
may be led. This is therefore the actual "net cross-sectional area
of the inlet opening" in this region. For example, with a
circularly round inlet opening, it is firstly assumed to be the
total circular area, but however the respective cross-sectional
area of the blades or the hub (including sheathing, rotor magnet
etc.) is subtracted for determining the net cross-sectional area.
The measure found here is thus a ratio of the actual rotor magnet
(with regard to area) to the actual cross section through which air
or another medium may flow.
[0008] The cross section applied for evaluating V.sub.QE preferably
runs through a region in which not only is the rotor magnet
present, but also a magnetically or electrically effective section
of the stator. Here, the cross section which is used preferably
lies perpendicular to the axis of the rotor.
[0009] Here, basically all substances capable of flowing are to be
understood as "media", e.g. gases, liquids, pastes, dusts or
granular substances.
[0010] One advantageous further formation envisages the smallest
diameter of the stator being 1.5-times to 8-times as large as the
largest outer diameter of the rotor magnet. In a flanking manner,
it is also possible for the smallest inner diameter of the stator
to be 1.1- to 1.49-times, preferably 1.25- to 1.49-times as large
as the largest outer diameter of the rotor. Likewise, it is
possible for the smallest diameter of the stator to be 8.01- to
15-times, preferably 8.01 to 12-times as large as the largest outer
diameter of the rotor.
[0011] The "largest outer diameter" of the rotor magnet is to be
understood as the diameter which the actual magnetically effective
material actually has (this without sheathing around the rotor
magnet). If the rotor magnet does not have a circularly round
shape, then the largest outer diameter is to be understood as the
largest possible inscribed circle in the respective cross section
of the magnet material.
[0012] The "smallest inner diameter of the stator" is to be
understood as the smallest diameter of the electrically or
magnetically actually effective stator. A shielding e.g. of a
plastic material from the stator towards the rotor, which for
example serves for corrosion protection, with this is not to be
seen as part of the stator, but only the smallest diameter of the
(as a rule metallic) electrically or magnetically effective parts
count. With regard to the motor according to the invention, it is
the case of a media gap motor, thus of a permanent magnet
synchronous motor with the particular characteristic of an
excessively large air gap between the stator and the rotor. This
large air gap permits the transport of various media between the
rotor and the stator in the axial direction. The rotor magnet here
may be directly coupled to a delivery device or also integrated
into this.
[0013] With conventional air gap motors, the smallest possible
constructional size for the desired torque as well as a high
magnetic flux with a lowest application of permanent magnetic
material is desired, with a conventional design of the motor
without the use of media/throughput function of the air gap. Thus
with conventional motors, one thus keeps the air gap small on
account of the fact that the magnetic resistance in the air gap is
larger than in the ferromagnetic part of the magnetic circuit.
[0014] The present media gap motor is basically constructed as a
conventional permanent magnet synchronous motor, but with the
particularity of a stator inner diameter which is overdimesionally
large compared to the outer diameter of the rotor or of the
permanent magnet.
[0015] In order to produce the required magnetic flux despite the
large gap between the rotor and the stator, and the high magnetic
resistance which this entails, as well as the high scatter share at
the pole transitions, it requires the application of magnets which
have a very high remanence and a very high energy density. In
particular, rare-earth magnet materials are suitable for this. The
magnet height simultaneously needs to be adapted accordingly. A
high motor efficiency with respect to the diameter of the rotor or
magnet may be achieved despite the relatively low flux, since a
relatively large winding area is available due to the large outer
diameter of the stator.
[0016] It is particularly amazing for the man skilled in the art,
that one may design a well functioning motor despite the unusually
large air gap.
[0017] Here, the large gap between the rotor and stator even
permits to rotor magnet to be displaced somewhat in the axial
direction (direction of the rotation axis) without the
characteristic values noticeably worsening by way of this.
[0018] The rotor of the electric motor preferably has a rotor
magnet which is surrounded by a sheathing. The rotor magnet is
mechanically protected by way of this. One may also have an
influence on the type of magnetic field in this manner. For example
here, a "beaker-like design" may be envisaged, into which the rotor
magnet is inserted, in order to give a rotor magnet which at the
end-side would otherwise be exposed to media, the best possible
protection. The sheathing of the rotor magnet here (just as
preferably the rotor magnet itself), is designed in an essentially
cylinder-like manner.
[0019] The electric motor preferably contains a stator which has an
essentially hollow-cylindrical shape and which surrounds the rotor
in a concentric manner. Here, it is advantageous that the stator
may be designed as part of the inner wall of the compressor
housing, for example of a compressor housing of a turbocharger. The
stator may for example also be applied as an insert into a
corresponding opening of the compressor housing. The advantage with
these embodiments is the fact that only an as small as possible
design change of conventional mechanical turbochargers is
necessary, so that cost- and competitive advantages may be realised
by way of this, in particular with large-scale production.
[0020] Apart from the variants mentioned above, which focus on the
outer surrounding of the stator, the stator may yet also be
provided with a shielding towards the rotor. This serves for the
protection of the stator, in particular for corrosion protection.
The shielding may preferably be given in the form of a thin tube or
flexible tubing, wherein this shielding is preferably designed of
electrically and magnetically not-conductive material.
[0021] Thus as a whole, the hollow-cylindrical design of the stator
is advantageous but not absolutely necessary.
[0022] The rotor may be designed in different manners. The motor
preferably has a rotor shaft, wherein this rotor shaft is mounted
in a simple or in a multiple manner over its length. In a
particularly advantageous embodiment, the rotor shaft is
essentially mounted on one side and projects out essentially freely
on the other side. Thus the necessity of a further bearing location
and, as the case may be, struts between the rotor and stator which
could further increase the throughput resistance, may be done away
with by way of this. A further embodiment envisages the rotor
magnet in the inside being hollow in regions, for placing on a
common shaft connected to a medium impeller or a medium conveyor
worm. An even better integration of the rotor shaft or the drive
shaft with the rotor magnet and even a part delivering medium
(medium impeller medium conveyor worm) may be effected in this
manner. It is advantageous on integrating the rotor magnet into the
rotor shaft or the medium impeller/medium delivery worm, for the
components adjacent to the rotor magnet to be of a material which
is not magnetically conductive or very poorly magnetically
conductive, preferably of reinforced or non-reinforced plastic, as
well as of metal which is not magnetically conductive.
[0023] A further advantages formation envisages the mounting of the
rotor shaft being non-lubricated or being lubricated by the medium
to be delivered itself (this is advantageous for example with
hydrodynamic bearings). As a whole, practically any media may be
considered for the delivery with the electric motor according to
the invention, specifically all gases (in particular air) as well
as liquid media (in particular aqueous, explosive, volatile,
sterile or highly pure media).
[0024] One particular advantage of the medium gap motor according
to the invention lies in the fact that the axial centre of the
stator and the axial centre of the rotor may be displaced in the
axial direction, and specifically by tenth up to a 1.5 times,
preferably a tenth to a fifth of the largest axial extension of the
rotor magnet. The electric motor according to the invention is
particularly suitable for the use in an electrically supported
turbocharger with a freely projecting electric motor, for the
transport of explosive gases, dusts, vapours, sticking substances,
pastes, liquids such as water or oil; decomposing products, such as
foodstuffs; in ventilation devices, in pumps, in particular in
pumps for aggressive media, such as salt water, chemical solutions
(in particular in the orthodontic field); in disinfectable or
sterilisable pumps, canned pumps (medium transport in the axial
direction), metering pumps, micro-pumps, disposable pumps,
multi-stage pump systems; for use in turbines, generators, delivery
worms for example for granular media, fluids or pastes; in gas-,
water- and steam turbines; in devices for measuring the media flow
via a generator voltage.
[0025] One advantageous further design envisages the rotor magnet
having a remanence between 0.3 Teslas and 0.8 Teslas, preferably
larger than 0.8 Teslas, particularly preferably larger than 1.2
Teslas. The flux density in the media gap here is between 0.05
Teslas and 0.5 Teslas, preferably more than 0.5 Teslas.
[0026] The present motor is thus fundamentally different to
previous developments. What is important here, is that an intended
leading of fluid or even a delivery of fluid through the gap
between the rotor and the stator is effected in a targeted manner,
and this is basically possible over the whole media gap.
[0027] Another particularity is that the media gap/air gap between
the rotor and the stator is designed in a relatively large manner,
as is clarified by the area relations or diameter relations. This
goes against common practice with regard to common electric motors,
with which a high magnetic flux with a low magnetic magnitude is
the main concern, or a large power density and therefore a compact
arrangement.
[0028] With regard to the present electric motor, it is to be
ascertained that the inner diameter and outer diameter of the
stator increase proportionally to the enlarged air gap. An increase
of the winding area results by way of this, thus also an increased
application of high-quality copper wire The specific resistance of
the stator winding reduces on account of the increased ratio of
copper wire to power.
[0029] In order to keep the demagnetisation factor as low as
possible, it is advantageous for the magnet to consist of solid
material, for example in the form of a solid cylinder. This solid
cylinder may be provided with an as small as possible bore for
mounting purposes. A division of the rotor magnet into segments is
thus not necessarily advantageous, but is also not ruled out,
however the single-piece design of the rotor magnet here appears to
be the most advantageous.
[0030] In order not to negatively influence the magnetic flux
within the media gap/rotor gap, no or only very weakly magnetically
conductive material should be installed in the over-dimensioned
gap. Likewise, the medium located in the gap should have no or only
weak magnetic characteristics. The relatively large media gap/rotor
gap when required, permits a complete insulation of the stator with
respect to the rotor. A shaft sealing of the rotating shaft with
respect to the stator is thus advantageously done away with. Thus a
medium accelerator which is secure against leakage arises.
[0031] The motor is to be designed as a synchronous motor. By way
of this, the rotational speed may be determined also electrically
in an exact manner, (which is different to the case with
asynchronous motors with slip), and thus a throughput control,
metering control or throughput measurement given a known delivery
quantity per rotor revolution are simultaneously possible.
[0032] A further advantageous design envisages that in at least one
cross section, the ratio of the cross-sectional area of the stator
to the cross-sectional area of the rotor magnet (expressed with
regard to a formula: V.sub.QS=A.sub.stator/A.sub.rotor magnet) is
between 2 and 100, preferably between 10 and 50. Here, it is in
each case the "net cross-sectional areas" of the electrically
effective components of the stator or rotor magnet which are to be
specified. Insulating components or components which are not
electrically/magnetically effective, are not taken into account.
Thus with a stator, a metal base body (including copper windings
for example) is taken into account in the cross-section, but not a
surrounding insulating plastic. Accordingly, with regard to the
rotor magnet, it is also only the actually magnetically effective
areas which are taken into account, even if the rotor consists of
different parts (the individual areas are then to be added
accordingly, so that one may evaluate a total area of the rotor
magnet). The mentioned cross section preferably lies perpendicular
to the axis of the rotor.
[0033] Further advantageous formations are specified in the
remaining dependent claims.
[0034] The invention is now explained by way of several figures.
There are shown in
[0035] FIGS. 1a to 1d: views of a turbocharger, with which the
electric motor according to the invention is applied,
[0036] FIGS. 2a and 2b: an illustratory picture of the magnetic
flux or cross-sectional views of an electric motor according to the
invention,
[0037] FIGS. 3 to 6: views or sections of further application
examples for the electric motor according to the invention.
[0038] FIG. 7: the distribution of the magnetic field in the rotor,
stator and air gap;
[0039] FIGS. 8a to 8d courses of voltage, current, torque as well
as power loss over the time axis;
[0040] FIGS. 9a and 9b views or sections of a further embodiment of
an application of an electric motor according to the invention;
[0041] FIG. 10a an explanation of the proportions and arrangement
of rotor magnet, stator and a compressor wheel;
[0042] FIG. 10b one embodiment of a compressor wheel with an
inclined rotor and an inclined stator;
[0043] FIG. 11 one explanation of geometric details with electric
motors according to the invention.
[0044] One application example of the invention is firstly shown by
way of the FIGS. 1a to 1d, by way of example.
[0045] FIGS. 1a to 1d show a turbocharger 1 which may be coupled to
a turbine housing 5 on an internal combustion engine. After the
combustion, the exhaust gas is collected by way of the exhaust gas
fans shown in FIG. 1a and is used for driving a turbine wheel 2.
The turbine wheel 2 is surrounded by the turbine housing 5 and is
essentially deduced from a conventional mechanical turbocharger. A
bearing housing 7 connects to the turbine housing 5, and then a
compressor housing 6. A compressor wheel is attached in this
compressor housing 6, and compresses the air fed through an inlet
opening (this inlet opening is in particular easily seen in FIG.
1c) and leads it to the combustion space of the internal combustion
engine in a manner which is not shown here. The compressor wheel 3
on the left side in FIG. 1a shows a continuation, to which a rotor
4a of an electric motor is given. The rotor 4a is attached
centrally in the inlet air opening 4e.
[0046] A stator 4b which has an essentially hollow-cylindrical
shape and is represented as part of the inner wall of the
compressor housing in the region of the inlet air opening, is
provided around the rotor 4a. Here, the stator 4b is even provided
as an insert into a suitable opening, so that this may be assembled
very easily. Here therefore in FIG. 1a, the rotor gap between the
rotor 4a and the stator 4b is the inlet air opening 4e for the
compressor wheel. With this, the inlet air opening 4e is free of
struts between the rotor and the stator also according to FIG. 1a.
The smallest inner diameter of the stator (see "d.sub.s" in FIG.
1d) is 1.5 times larger than the largest outer diameter d.sub.R of
the rotor.
[0047] The rotor 4a of the electric motor 4 comprises a rotor
magnet 4c which here is surrounded by an sheathing (see e.g. FIG.
1d). With this, the sheathing is designed in an essentially
"beaker-shaped" manner, wherein the base of the beaker is almost
completely closed towards the compressor wheel (disregarding a
centric assembly bore).
[0048] The compressor wheel may (but need not) be of a non-metallic
material, here with one embodiment, for example of a plastic, and
the influence on the electromagnetic field of the electric motor is
minimised. The rotor magnet 4c in turn is hollow in regions for
placing on a common shaft with the compressor wheel. Here, a bore
4c of the rotor magnet is to be accordingly seen in FIG. 1d.
Furthermore, it may be seen that a sequence of elements is shown in
the sequence of the rotor (consisting of the rotor magnet 4c and
sheathing 4d), the compressor wheel 3, shaft 8, turbine wheel 2,
which minimises a thermal loading of the electric motor. The shaft
8 here in the present embodiment is designed such that the turbine
wheel 2, compressor wheel 3 as well as rotor 4a are firmly
(rotationally fixedly) connected to one another, thus may not be
separated by a rotation clutch or free-wheel.
[0049] However, it is basically possible to provide such a clutch
within the framework of the present invention, if it is the case
for example that the turbine wheel 2 is very high, but however the
design effort would in turn also be increased by way of this.
[0050] The nominal voltage of the electric motor 4 in FIG. 1a here
is 12 V, but other voltages (for example 48V for hybrid vehicles)
are also possible.
[0051] The electric motor may be operated in motor operation (for
accelerating and avoiding a "turbolag"), as well as in generator
operation (for recovering energy). If the charging pressure (in the
turbine housing) reaches a certain nominal value, then additional
energy is produced by way of using a converter capable of return
feed. Ideally, one may do away with a wastegate/pressure dose for
blowing out excess exhaust gas pressure, as is represented in FIG.
1b, numeral 9, by way of this energetic conversion of the braking
energy in generator operation.
[0052] The turbocharger according to the invention is used in a
drive system according to the invention for motor vehicles which
contain an internal combustion engine connected to the
turbocharger, as well as a storage device for electrical energy.
The electric motor of the turbocharger 1 here is connected to the
storage device for electric energy for taking electrical energy in
a motor operation of the turbocharger 1, and for feeding in
electrical energy in a generator operation of the turbocharger. In
a particularly preferred embodiment, the electric motor of the
turbocharger is connected to an electrical storage device, wherein
this electrical storage device is additionally connectable to an
electromotoric drive of a motor vehicle. This may be a "hub motor"
of a motor vehicle or another electric motor, which is provided in
the drive train of a motor vehicle (for example in the region of
the gear). This connection of the electrical turbocharger to a
hybrid vehicle is particularly energy efficient.
[0053] Control electronics for determining the rotational speed of
the turbine wheel 2 or the compressor wheel 3, actual values of
pressure conditions on the turbine housing side and compressor
housing side, as well as further values relevant to the torque for
the internal combustion engine are provided for the efficient
control of the drive system or the turbocharger.
[0054] FIG. 2a shows a field line representation of the magnetic
flux between the rotor 4a and the stator 4b.
[0055] FIG. 2b once again shows the geometric particulars of the
electric motor according to the invention. Here one may see a
solid-cylindrical rotor magnet which has a largest diameter
d.sub.RM. A sheathing 4d is attached around this rotor magnet 4c.
In turn, a medium impeller 10a is attached on this sheathing. A
medium passage opening 4e is given around the media impeller 10a
and this is surrounded radially outwardly by a shielding 11. The
actual stator 4b, whose outer diameter is specified at d.sub.s, is
then given around the shielding 11.
[0056] With the exemplary electric motor, the remanence is 1.28
Teslas, the energy density 315 kJ/m.sup.3 and the rotor magnet
consists of NdFeB.
[0057] Here then, an electric motor 4 for the delivery of media is
shown, wherein this comprises a stator 4b, a rotor 4a with a rotor
magnet 4c, as well as a media passage opening 4e between the stator
and rotor. The smallest inner diameter d.sub.s of the stator, here
is 1.5-times to 8-times, preferably 2-times to 4-times as much as
the largest outer diameter of the rotor magnet itself (d.sub.RM),
in the present case d.sub.s=2.times.d.sub.RM.
[0058] The rotor magnet is preferably surrounded with a sheathing
for the protection from media or damage or for the protection from
centrifugal force at greater peripheral speeds. This may be
designed in a beaker-like manner. The stator is preferably designed
as an insert into a corresponding opening of a surrounding housing.
A shielding 11 is preferably provided to the inside, thus towards
the media passage opening, and this protects the stator from
corrosion and improves the flux characteristics.
[0059] This is preferably designed in the shape of a tube, wherein
the tube is of an electrically and magnetically non-conductive or
poorly conductive plastic e.g. glass fibres, alternatively e.g. of
glass, cast epoxy resin or rubber. The rotor particularly
preferably has a rotor shaft, wherein this rotor shaft is mounted
in a simple or multiple manner over its length. The rotor shaft
here is preferably mounted on one side and thus in a "projecting"
manner.
[0060] The flow resistance through the rotor is further reduced by
way of this. The rotor magnet is preferably placed on a common
shaft with a media impeller or a media conveyor worm or is
integrated in the inside and thus centred straight away. One may
again attach a media impeller or a media conveyor worm around the
motor magnet (these have recesses for receiving the rotor magnet),
so that an as large as possible integration of the components is
possible.
[0061] FIG. 3 shows a use of an electric motor which comprises a
media impeller 10a of a plastic material. A rotor magnet 4c is
attached on the end-side of this media impeller 10a. Bearing
locations 12 mount a rotor shaft 8 which is screwed in the medium
impeller. A stator 4b is accommodated in an inner wall of a housing
6. The flow of a medium 13 is introduced from the left, and is
conveyed towards the right by the media impeller 10a. Preferably,
in the present case, again there is a large gap width not only
radially about the axis 14, but also axially in the direction of
the axis 14. This is also due to the fact that the axial centre of
the stator AZS and the axial centre of the rotor AZR are displaced
in the axial direction, and specifically by a tenth to a fifth of
the largest axial extension GAAR of the rotor magnet.
[0062] FIG. 4 shows a representation corresponding essentially to
FIG. 3, wherein here a shielding 11 is additionally provided, which
protects the stator from the medium 13.
[0063] FIG. 5 shows a further embodiment of a pump according to the
invention or of a throughput meter according to the invention, with
which three propellers 10a are mounted on a rotor shaft 8. With
this, the bearings are attached on the left, as well as on the
right side of the three media impellers 10a. The stator 4b is
attached in the axial direction with respect to the axis 14 centred
about the rotor magnet 4c. The media impellers have an inner cavity
which accommodates the rotor shaft 8 or the rotor magnets 4c
located therein. A particularly simple and securely mounted device
is given in this manner, and by way of suitable webs, on the one
hand the retention of the rotor shaft 8 is ensured, and also an
adequate throughput of media 13 is achieved on account of the
relatively small web cross sections.
[0064] FIG. 6 shows an embodiment example which is quite similar to
FIG. 5. However, here a media conveyor worm 10b is provided instead
of the three individual impellers 10, and this seals media towards
the shielding 11 in a particularly good manner.
[0065] FIG. 7 shows a representation of the distribution of the
magnetic field in the region of the stator 4b, the rotor 4a or
rotor magnet 4c, as well as the media gap/inlet opening. The
chambers shown in the stator are hollow inclusions of the
surrounding sheet-metal inlay, and these are wrapped around with
copper wire.
[0066] One may recognise in FIG. 7 that the field lines at the pole
transitions are short circuited without flooding the stator. Since
the magnetic field is provided by the permanent magnets without
losses, this has no negative influence on the efficiency of the
motor.
[0067] FIGS. 8a to 8d show courses of voltage, current, torque as
well as power losses over the time axis.
[0068] The figures do not show any special characteristics, but
despite the large air gap, the characteristic lines are typical of
a synchronous motor.
[0069] FIGS. 9a and 9b show a further embodiment of an application
for an electric motor according to the invention.
[0070] Here, a possibility is shown of leading tubes or conduits
through the air gap. These tubes serve for leading through media
(e.g. fluids, pastes, granulates or gases) and are thus suitable
for painting installations or for blasting treatment (e.g. sand
blasting, glass pearl blasting etc.) of workpieces. Different types
of media may be led through different tubes (e.g. various
colours).
[0071] One should take care that these tubes should have no or only
weakly magnetic characteristics. Electrical current may be led
through these conduits, but influences the magnetic flux and thus
the power (torque/rotational speed/true running) of the motor and
is therefore to be accordingly taken into account on designing the
total arrangement.
[0072] FIG. 9a shows a plan view in which tubes 15 (3 pieces, for
example painting tubes) are arranged parallel to a middle axis 10.
The rotor 4a or rotor magnet 4c is arranged centrally in the middle
axis 10. The stator 4b is attached separated by a tube or a
shielding/sheathing 11.
[0073] FIG. 9b shows a cross section according to B-B. On this, one
may see medium flows from the left to the right in the picture
through the tube 15, and hits an acceleration disk 16, by which
means a dispersion of the medium is effected and subsequently a
painting, for example of a vehicle. The acceleration disk 16 is
connected to the rotor 4a which comprises a rotor magnet 4c. The
rotor magnet 4c together with the rotor 4a is mounted on bearings
L1 and L2 and the drive is effected via the stator 4b lying outside
the shielding/sheathing.
[0074] FIG. 10a shows a schematic representation of the compressor
wheel 3, the stator 4b as well as the rotor 4c for illustrating the
geometric conditions. What is shown is the compressor wheel which
is mounted on a shaft 10 on one or on both sides, and is subjected
to flow in an air inlet flow direction LES. The air flow which
flows in, is accelerated by the compressor wheel 3 which comprises
a conveyor structure F. The front edge of the conveyor structure is
indicated at VF, and the rear edge of the delivery structure is
indicated at HF. The front edge of the rotor magnet 4c is indicated
at VR and the rear edge of the rotor magnet 4c is indicated at HR.
The front edge of the stator is indicated at VS, and the rear edge
of the stator is indicated at HS (the stator here is rotationally
symmetrical, but here the upper stator section has been shown for
reasons of a better overview). The compressor wheel 3 thus has a
conveyor structure F in the form of blades, wherein the front edges
VF of the conveyor structure, in the air inlet flow direction, lie
downstream with respect to a magnetically effective front edge of
the rotor magnet 4c and a magnetically effective front edge VS of
the stator. The compressor wheel with its rear edge HF in contrast,
in the air inlet flow direction, lie upstream with respect to the
rear edge HR of the rotor magnet 4c as well as the rear edge of the
stator 4b.
[0075] However, other arrangements are also possible here, with
which the rotor magnet or stator only project beyond one edge of
the compressor wheel, and it is also possible for the rotor magnet
to lie completely within the compressor wheel, and thus to be
laterally enclosed by the edges of the conveyor structure.
[0076] FIG. 10b shows a further embodiment, with which the stator
4b (this is rotationally symmetrical with respect to the axis 10),
is inclined with respect to the axis 10. The stator thus here has
essentially the shape of a hollow truncated cone. The same also
applies to the rotor 4a or the respective rotor magnets, and this
too with its sections, is inclined with respect to the axis 10
(thus these are not parallel/co-linear, but would intersect in
their extensions).
[0077] The compressor wheel shown in FIG. 10b is mounted on both
sides (see indicated bearing locations L1 and L2). However, the
embodiment forms of the further figures may basically also be
mounted on both sides (even if this, under certain circumstances,
means more constructional effort).
[0078] With regard to FIG. 10b, it is the case that the rotor
magnet 4c is arranged radially outside the hub of the compressor
wheel with respect to the axis 10 of the compressor wheel 3. The
compressor wheel here is designed such that air may be led radially
within, as well as radially outside the rotor magnet. Here, the
compressor wheel is also designed such that at least 70% of the
supplied air mass (or of the supplied air mass flow), is led
radially outside the rotor magnet.
[0079] FIG. 11 once again shows a cross section through a stator 4b
and rotor 4a, according to the invention. Here one may see a rotor
magnet 4c which consists of individual segments (four distributed
over the periphery). Alternatively to this, one may also imagine
e.g. a cylindrical single magnet for example. A sheathing 4d is
attached around this rotor magnet 4c. In turn, a conveyor structure
F (here in section, therefore hatched) is shown on this sheathing.
An air passage or media passage opening 4e is given around the
conveyor structure and is surrounded radially to the outside by a
shielding 11 (this is of plastic and is magnetically/electrically
insulating). The electrically effective part of the stator 4b is
given around the shielding 11.
[0080] In the cross section shown in FIG. 11, the cross-sectional
area of the media passage opening or the air passage or the inlet
opening 4e, to the cross-sectional area of the four segments of the
rotor magnet (defined as V.sub.QE=A.sub.inlet opening/A.sub.rotor
magnet)=4:1.
[0081] Here, the inlet opening 4e is defined as the opening which
may indeed be subjected to through-flow, thus the area content
within the sheathing 11, but minus the areas of the hatched
conveyor structure, as well as the hub of the rotor (the hub
includes the sheathing 4d as well as everything located therein).
What is meant here is the "net cross-sectional area" of the inlet
opening. The cross section in FIG. 5c visibly runs through the
electrically and magnetically effective section of the stator 4b.
In this cross section, the ratio of the cross-sectional area of the
stator to the cross-sectional area of the rotor magnet (defined as
V.sub.QS=A.sub.stator/A.sub.rotor magnet)=13:1.
[0082] Here, only the electrically or magnetically effective part
(thus core metal+copper wire, however minus copper wire coating as
well as possible "hollow areas") is to be understood as the
cross-sectional area of the stator. Accordingly, it behaves as with
the rotor magnet, and here only the cross sections of the pure
rotor magnet segments in this cross section are applied.
[0083] The above-mentioned ratios for the relation of the smallest
inner diameter of the stator to the largest outer diameter of the
rotor, supplementary to 1.5 to 8-fold, may also lie in other
intervals, specifically 1.1- to 1.49-fold, preferably 1.25- to
1.49-fold. Accordingly however, at the other end of the scale, the
smallest inner diameter of the stator may also be 8.01- to 15-fold,
preferably 8.01- to 12-fold the size of the largest outer diameter
of the rotor.
* * * * *