U.S. patent application number 10/678334 was filed with the patent office on 2004-06-03 for drive system, especially for a motor vehicle.
This patent application is currently assigned to ZF Sachs AG. Invention is credited to Denner, Armin, Hirschmann, Frank, Lindner, Joachim, Steinel, Klaus, Welke, Knut.
Application Number | 20040104630 10/678334 |
Document ID | / |
Family ID | 32010176 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040104630 |
Kind Code |
A1 |
Denner, Armin ; et
al. |
June 3, 2004 |
Drive system, especially for a motor vehicle
Abstract
A drive system which has a drive unit with a drive shaft; a
centrifugal mass arrangement, which is mounted on the drive shaft;
and an electrical machine, comprising a stator arrangement and a
rotor arrangement, where the rotor arrangement is mounted on the
centrifugal mass arrangement, and where the stator arrangement and
the rotor arrangement are adjacent to each other in the radial
direction. So that optimum use can be made of the space available
inside the drive unit, and so that the overall length of the drive
unit required in the axial direction relative to the axis of
rotation (A) can be kept as short as possible, the centrifugal mass
arrangement has a contour such that, relative to the axis of
rotation (A), a receiving space (71) is formed radially inside the
electrical machine. The receiving space is bounded on at least one
side by the centrifugal mass arrangement, and at least one
additional component of the drive unit is installed in the
receiving space.
Inventors: |
Denner, Armin; (Werneck,
DE) ; Welke, Knut; (Sulzheim, DE) ; Steinel,
Klaus; (Bergrheinfeld, DE) ; Lindner, Joachim;
(Dittelbrunn, DE) ; Hirschmann, Frank;
(Niederwerrn, DE) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE
551 FIFTH AVENUE
SUITE 1210
NEW YORK
NY
10176
US
|
Assignee: |
ZF Sachs AG
|
Family ID: |
32010176 |
Appl. No.: |
10/678334 |
Filed: |
October 3, 2003 |
Current U.S.
Class: |
310/75R ;
903/951; 903/952 |
Current CPC
Class: |
B60L 50/16 20190201;
Y02T 10/62 20130101; B60L 2210/40 20130101; Y02T 10/7072 20130101;
B60K 6/40 20130101; Y02T 10/64 20130101; B60K 2006/268 20130101;
B60K 6/48 20130101; Y02T 10/72 20130101; B60K 2006/264 20130101;
B60L 3/0061 20130101; Y02T 10/70 20130101; B60L 2220/14 20130101;
B60L 2240/36 20130101; B60K 6/405 20130101; H02K 7/006 20130101;
B60L 7/14 20130101 |
Class at
Publication: |
310/075.00R |
International
Class: |
H02K 007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 4, 2002 |
DE |
102 46 227.5 |
Claims
What is claimed is:
1. A drive system for a motor vehicle, said drive system
comprising: a drive shaft; a centrifugal mass mounted on said drive
shaft for rotation about an axis and being profiled with an axial
receiving space; an electrical machine comprising a rotor mounted
on the centrifugal mass and a stator arranged radially with respect
to said rotor; and at least one component accommodated in said
receiving space.
2. A drive system as in claim 1 wherein said electrical machine is
mounted on a side of said centrifugal mass which is mounted to said
drive shaft.
3. A drive system as in claim 1 further comprising a housing having
at least one part, said centrifugal mass and said electrical
machine being arranged in said housing.
4. A drive system as in claim 3 further comprising a stator bracket
which attaches said stator to said housing.
5. A drive system has in claim 4 further comprising a cooling
channel in said stator bracket.
6. A drive system as in claim 4 wherein said stator bracket bounds
said receiving space radially.
7. A drive system as in claim 1 wherein said centrifugal mass
comprises a radially inner first area, a radially outer second
area, and a third area connecting said first and second areas,
which are offset both radially and axially.
8. A drive system as in claim 7 wherein said first area and said
third area bound two sides of said receiving space.
9. A drive system as in claim 1 wherein said centrifugal mass
comprises a first area and a second area which are connected to
each other at an angle.
10. A drive system as in claim 9 wherein said first area comprises
an attachment area for attaching said centrifugal mass to said
drive shaft, and said second area comprises an attachment area for
attaching said rotor, said second area having at least one through
opening.
11. A drive system as in claim 9 wherein said first and second
areas bound two sides of said receiving space.
12. A drive system as in claim 1 further comprising a clutch, said
clutch comprising said component accommodated in said receiving
space.
13. A drive system as in claim 12 wherein said clutch comprises a
clutch disk arrangement, said clutch disk arrangement comprising
said component in said receiving space.
14. A drive system as in claim 12 wherein said clutch comprises an
actuating device, said actuating device comprising said component
accommodated in said receiving space.
15. A drive system as in claim 14 wherein said actuating device
comprises an actuator, said actuator comprising said component
accommodated in said receiving space.
16. A drive system as in claim 15 further comprising a housing
having at least one part, said centrifugal mass and said electrical
machine being arranged in said housing, and a stator bracket
attaching said stator to said housing, said stator bracket having
an inner surface, said actuator comprising a cylinder formed by
said inner surface.
17. A drive system as in claim 12 wherein said clutch comprises a
diaphragm spring which is accommodated in said receiving space.
18. A drive system as in claim 1 wherein said at least one
component comprises at least one torsion damper.
19. A drive system as in claim 1 wherein said electrical machine is
a starter-generator.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention pertains to a drive system, especially
for a motor vehicle, having a centrifugal mass mounted on a drive
shaft and an electrical machine with a rotor mounted on the
centrifugal mass and a stator arranged radially with respect to the
rotor.
[0003] 2. Description of the Related Art
[0004] Drive systems of this type can be designed in many different
ways and usually have, first, a prime mover. A prime mover of the
type in question can be, for example, a combustion machine such as
an internal combustion engine or the like. Drive systems of the
known type also usually have a drive unit, which can be built up in
turn out of various components. For example, the drive unit can
have a drive shaft, by means of which the torque produced by the
prime mover can be transmitted to other components. The drive unit
can also include a centrifugal mass arrangement, which is mounted
on the drive shaft. The drive unit can also have an electrical
machine.
[0005] In general, these electrical machines can be rotating
machines, for example, which use a magnetic field to convert
electrical energy into mechanical energy according to the motor
principle or mechanical energy into electrical energy according to
the generator principle.
[0006] These types of electrical machines, which can be designed
either as synchronous machines or as asynchronous machines, usually
have a first machine component and a second machine component. The
two machine components rotate relative to each other or can be
rotated relative to each other. The two machine components are
mounted adjacent to each other in the radial direction. One of the
two machine components is usually mounted radially inside the other
machine component with respect to the axis of rotation of the
electrical machine. Depending on the design of the electrical
machine, one of the machine components can be a rotor arrangement
and the other machine component can be a stator arrangement. The
stator arrangement, also called simply the stator, is usually the
stationary part, whereas the rotor arrangement, also called simply
the rotor, is the rotating part.
[0007] Depending on the design of the electrical machine, the
stator component consists, for example, of a sheet packet, which
forms a yoke and a number of teeth. The electrical windings are
laid in the grooves between the teeth. The magnetic field of the
electrical machine is produced when current passes through these
windings. The rotor arrangement consists, for example, of a sheet
packet, on which a number of magnets, possibly permanent magnets,
are mounted.
[0008] One of the areas in which electrical machines are used is
that of vehicles of all types. In vehicles, electrical machines are
used in their function as generators. When these electrical
machines thus operate according to the generator principle, they
produce electrical energy, which can then be made available to
other consumers. In another application in vehicles, electrical
machines are used as starter-generators, for example. A
starter-generator is an electrical machine which is mounted between
the drive shaft of a prime mover, such as the crankshaft of an
internal combustion engine, and a component of the drive unit,
possibly a clutch, a gearbox, or the like, in the drive system of
the vehicle. The starter-generator can be used, first, to start the
prime mover. Once the vehicle is in operation, it can also operate
as a generator and can therefore replace both the starter and the
generator in the vehicle.
[0009] In addition to the components already described above, the
drive unit can also include other components, which can include,
for example, a clutch, a gearbox, a torque converter, etc.
[0010] A drive system of this type is described in, for example, DE
199 27 261. These types of drive systems are used to advantage in
motor vehicles. Especially in the vehicle sector, however, the need
to reduce the amount of space required for the drive system is
increasing. This can be explained by advances in engineering, which
make it necessary to accommodate ever-increasing numbers of
components in the engine compartment of the vehicle. The solution
disclosed in the publication cited above already offers a way to
reduce the space required to accommodate the drive system.
SUMMARY OF THE INVENTION
[0011] Proceeding from the state of the art cited above, the object
of the present invention is to improve the drive system of the type
described above so that the available space is utilized to the best
possible degree and so that the axial length of the drive system
can be kept as short as possible. In addition, an especially
advantageous use of drive system of this type is to be
presented.
[0012] The present invention is based on the insight that
additional space, which can be used to accommodate components of
the drive unit, can be created by designing the centrifugal mass
arrangement in a special way.
[0013] According to the first aspect of the invention, the
centrifugal mass arrangement has a contour such that a receiving
space is formed radially inside the electrical machine; the
receiving space is bounded on at least one side by the centrifugal
mass arrangement; and at least one additional component of the
drive unit is accommodated in the receiving space.
[0014] As a result of the drive system according to the invention,
an additional receiving space is created, in which additional
components of the drive unit can be accommodated. According to the
invention, the additional receiving space is formed in the area of
the electrical machine. Giving the centrifugal mass arrangement a
special contour creates the additional receiving space.
[0015] The electrical machine has, first, a stator arrangement and
a rotor arrangement, which rotate relative to each other or which
can be rotated relative to each other. Depending on the design of
the electrical machine, either the rotor arrangement or the stator
arrangement can be mounted radially inside the other arrangement
with respect to the axis of rotation of the electrical machine.
When the electrical machine is of the external rotor type, the
stator arrangement is mounted radially inside the rotor. In the
case of an electrical machine of the internal rotor type, the rotor
will be radially inside the stator. The present invention is not
limited to one specific type of electrical machine. Electrical
machines of the external rotor type and those of the internal rotor
type can both offer advantages. Synchronous machines, especially
synchronous machines excited by permanent magnets, and asynchronous
machines can be cited as examples of suitable electrical
machines.
[0016] The centrifugal mass arrangement according to the invention
has a contour such that a receiving space is formed radially inside
the electrical machine, that is, radially inside the rotor
arrangement or radially inside the stator arrangement. "Radially
inside" is to be interpreted again in relationship to the axis of
rotation of the electrical machine. When the electrical machine is
installed in a drive system of the type described above, it is
advantageous for the axis of rotation of the electrical machine to
be the same as the axis of rotation of the drive shaft and the same
as the axis of rotation of other power takeoff shafts downline from
the drive shaft.
[0017] Additional components of the drive unit can be accommodated
in the receiving space formed by the special design of the
centrifugal mass arrangement. Thus optimum use is made of the space
available. At the same time, the overall axial length of the drive
unit and thus of the overall drive system is further reduced. The
axial orientation is again based on the axis of rotation of the
electrical machine or on the previously mentioned axis of rotation
of the drive unit.
[0018] Thus the invention is not limited to specific types of
components or to specific numbers of components, which can be
mounted in the receiving space. The type and number of components
depend on the size, type, and area of application of the electrical
machine and of the drive unit or drive system. A few nonexclusive
examples of components, which can be installed advantageously in
the receiving space, will be described in greater detail below in
the further course of the specification.
[0019] According to the invention, the rotor arrangement is mounted
on the centrifugal mass arrangement. This has the effect of
reducing the required space, but it also has the effect of
increasing the mass moment of inertia of the centrifugal mass
arrangement.
[0020] So that axial misalignments which could occur as a result
of, for example, the powerful forces of the permanent magnets in
the rotor arrangement can be prevented, it is advantageous for the
stator and the rotor to be connected to each other by suitable
fastening means such as screws, bolts, or the like until after they
have been mounted in the drive unit.
[0021] It is advantageous for the drive system to have a prime
mover in which the electrical machine is installed axially between
the prime mover and the centrifugal mass arrangement. "Axially" is
to be interpreted here again in relationship to the axis of
rotation of the electrical machine or to the axis of rotation of
the drive unit or of the drive system. As already explained above,
it is advantageous for these axes of rotation to be the same. In
this type of design, the electrical machine is mounted on the side
of the prime mover that faces the flywheel arrangement. As a
result, a drive unit with an especially compact design can be
achieved, and thus the design of the entire drive system becomes
especially compact.
[0022] The invention is not limited to a specific type of prime
mover. The prime mover can consist, for example, of a combustion
machine such as an internal combustion engine or the like.
[0023] It can be advantageous to install the drive unit in a
one-part or multi-part housing. If a multi-part housing is used, a
spacer element such as a spacer ring or the like can be provided
between the individual parts of the housing. A spacer element of
this type makes it possible to compensate easily for any
discrepancies in length that may be present. Thus the individual
parts of the housing can be produced with a predetermined geometric
contour, but it will still be possible to install the housing parts
in different drive systems. Any length discrepancies that may be
present can be easily and inexpensively corrected by the use of
spacer elements of suitable size. It is conceivable, for example,
that the spacer element could be designed as an independent
structural component. It is also conceivable that the spacer
element could be an integral part of one of the housing parts.
[0024] It can be advantageous to attach the stator arrangement to
the housing by the use of a stator bracket. The housing can be, for
example, the bell of the centrifugal mass arrangement. It is also
possible, of course, for the stator bracket to be attached directly
to the prime mover.
[0025] In a further elaboration, it is possible for the stator
bracket to have a cooling device. This cooling device can be used
effectively to cool the individual components of the electrical
machine, especially the stator arrangement. As will be explained in
greater detail in the further course of the specification, the
cooling device can also be used, if desired, to cool additional
components or parts of additional components which are mounted in
the receiving space according to the invention.
[0026] If care is taken to mount the stator bracket appropriately
on the housing of the drive unit or directly on the prime mover, it
is possible for the cooling device in the stator bracket to be
connected to the cooling device of the prime mover, so that the
stator bracket can be cooled by the cooling device of the prime
mover. In the case of an internal combustion engine, this means
that the bracket would be cooled by the engine cooling water or by
motor oil.
[0027] It can be advantageous for the stator bracket to form one of
the boundaries of the receiving space.
[0028] In a further elaboration, the centrifugal mass arrangement
can have two areas, which are arranged radially with respect to
each other. "Radial" is based here on the axis of rotation of the
centrifugal mass arrangement, which is advantageously the same as
the axis of rotation of the drive shaft on which the centrifugal
mass arrangement is mounted. One of the two areas is thus farther
inward in the radial direction with respect to the axis of rotation
than the other area.
[0029] It is also advantageous for the two areas mentioned to be
offset from each other in the axial direction. "Axial" here again
is based on the axis of rotation of the centrifugal mass
arrangement. The centrifugal mass arrangement thus acquires a
step-like design.
[0030] To achieve this, the two areas are connected to each other
by a third connecting area.
[0031] It can advantageous for the centrifugal mass arrangement to
be made in the form of a "pot", which extends around the electrical
machine. This pot is formed in particular by the connecting area
and by the area of the centrifugal mass arrangement that is
situated radially farther outward with respect to the axis of
rotation. In this way, the components of the electrical machine are
also well protected at the same time. It can be advantageous for
the radially outer area and the connecting area to form two sides
of a protected space of this type. A third side of the protected
space can be formed by, for example, the housing wall. Depending on
the design of the housing of the drive unit, the fourth wall of the
protected space can be formed either also by a wall of the housing
or by a wall of the prime mover.
[0032] As a further elaboration, the radially inner area of the
flywheel arrangement and the connecting area can form two sides of
the receiving space.
[0033] In a different embodiment, the centrifugal mass arrangement
can have two areas which are connected to each other and which are
oriented at an angle to each other. In this way, the centrifugal
mass arrangement can be produced in an especially simple and
low-cost manner. It can be provided that the flywheel arrangement
is produced as a single piece. It is also conceivable that the
individual areas of the flywheel arrangement are first produced
separately and then connected to each other.
[0034] It is advantageous in this case for the two areas of the
flywheel arrangement to be oriented at an angle to each other. The
invention is not limited to specific angles, however. For example,
the two areas can be oriented at an angle of 90.degree. to each
other. In this case, the centrifugal mass arrangement has an
approximately L-shaped contour. Other angles and thus also other
contours of the centrifugal mass arrangement are also possible, of
course, so that the invention is not limited to the examples
cited.
[0035] It can be advantageous for a first area of the centrifugal
mass arrangement to be designed as an attachment area for the
attachment of the centrifugal mass arrangement to the drive shaft.
A second area of the centrifugal mass arrangement can then be
designed as a receiving area for the rotor arrangement. In certain
special cases, furthermore, it can advantageous for this second
area of the centrifugal mass arrangement to have at least one
through-opening. Such through-openings are especially helpful when
components, which must extend at least partially out of the
receiving space, are mounted in the receiving space. Several
nonexclusive examples of this will be explained in greater detail
in the further course of this specification.
[0036] It can be advantageous for the two areas of the centrifugal
mass arrangement to form two sides of the receiving space.
[0037] As already presented in the introduction to the
specification, the drive unit can comprise many different
components and assemblies. These can include, for example, a
gearbox, a torque converter, etc. The drive unit can preferably
also have a clutch. In this case, it is preferable for at least one
component of the clutch to be accommodated in the receiving
space.
[0038] The invention is not limited to specific types of clutches.
For example, the clutch can be a friction clutch or some other type
of clutch.
[0039] If the drive system has a prime mover and a drive unit
connected to it, at least one component of the clutch in an
embodiment of this type will therefore be situated in front of the
centrifugal mass arrangement on the side facing the prime
mover.
[0040] It is possible, for example, for at least one component of a
clutch disk arrangement of the clutch to be accommodated in the
receiving space.
[0041] It is also conceivable that at least one component of an
actuating device of the clutch could be accommodated in the
receiving space. The actuating device of the clutch can be designed
in any desired way. For example, the actuating device can be a
hydraulic slave cylinder, a pneumatic actuator, or the like.
Because of the special design of the drive unit, it is advantageous
for the actuating device to have a concentric design. "Concentric"
is based here on the axis of rotation of the centrifugal mass
arrangement or on the axis of rotation of the electrical
machine.
[0042] If the actuating device of the clutch has an actuator, at
least some of the components of the actuator can be advantageously
accommodated in the receiving space formed by the centrifugal mass
arrangement.
[0043] For example, the actuator can be designed so that it has a
cylinder. It can be advantageous in this case for the cylinder to
be formed by the inside surface of the stator bracket described
above. In this way, the stator bracket forms not only the
appropriate areas of the centrifugal mass arrangement but also one
of the other sides of the receiving space. A design of this type
offers the advantage that the conventional cylinder normally
required for the actuator can be eliminated. This leads, first, to
cost savings in the production of the actuator. The design also
leads to a further reduction in the amount of space required.
Finally, the design makes it possible to cool the actuator in a
very simple manner, because the actuator can be cooled by the same
system that cools the stator bracket.
[0044] It can be advantageous for the clutch to have a diaphragm
spring. At least part of this diaphragm spring can be accommodated
in the receiving space.
[0045] Because one or more parts of the clutch can be installed in
the receiving space, the overall axial length of the drive unit and
thus of the drive system becomes very short.
[0046] In another embodiment, at least one torsion damper can be
accommodated in the receiving space. It is especially advantageous
to use the receiving space to hold a double arrangement or a
multiple arrangement of torsion dampers. All the torsion dampers
can, for example, be connected by a set of external teeth to a
large, internally toothed sleeve or hub, which carries in turn a
common cover ring. The creation of a receiving space according to
the invention now makes it easy to install two or more torsion
dampers without increasing the amount of space required. This also
leads to an especially good isolation of the vibrations.
[0047] The centrifugal mass arrangement can be designed in many
different ways within the scope of the invention. The centrifugal
mass arrangement can be, for example, the flywheel of a clutch,
possibly of a friction clutch. In another embodiment, the
centrifugal mass arrangement can be, for example, a torque
converter, preferably its housing.
[0048] It is especially advantageous for the electrical machine to
be designed as a starter-generator. A starter-generator of the type
in question will be used increasingly in the future as a
replacement for the current combination of separate components,
namely, a starter and a generator. In comparison with past
solutions, a starter-generator offers better efficiency, lower
weight, and greater electrical power. In the future, energy
consumers, which are driven mechanically today, will be driven by
electricity instead. A starter-generator can be used not only to
start and to stop a prime mover, such as an internal combustion
engine, but also to take over various other functions during the
operation of the engine such as braking functions, booster
functions, battery management, active vibration damping,
synchronization of the prime mover, etc.
[0049] As described above, the starter-generator can be mounted
advantageously in the same area as that occupied by the centrifugal
mass arrangement, such as a flywheel, or it can be integrated into
this arrangement; the starter-generator will therefore be safely
protected in a housing. If, from the perspective of the prime
mover, a clutch is located behind the centrifugal mass arrangement,
the starter-generator will also be inside the clutch bell, which
usually surrounds a clutch. As a result of the special design of
the centrifugal mass arrangement, i.e. the creation of an
additional receiving space, an especially favorable, compact
arrangement of the individual components is found in this area of
the drive unit, which comprises, for example, a pressure plate
arrangement of a clutch, a clutch disk arrangement, a clutch
actuating device, and possibly an intermediate flywheel. Optimum
use is made of the space available to house these components, and
the overall axial length of the drive unit can be kept as short as
possible.
[0050] According to a second aspect of the invention, a drive
system according to the invention as described above can be used to
particular advantage in a commercial vehicle (truck).
[0051] Other objects and features of the present invention will
become apparent from the following detailed description considered
in conjunction with the accompanying drawings. It is to be
understood, however, that the drawings are designed solely for
purposes of illustration and not as a definition of the limits of
the invention, for which reference should be made to the appended
claims. It should be further understood that the drawings are not
necessarily drawn to scale and that, unless otherwise indicated,
they are merely intended to conceptually illustrate the structures
and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] FIG. 1 shows a longitudinal cross section through a first
embodiment of the drive system according to the invention;
[0053] FIG. 2 shows a longitudinal cross section through a second
embodiment of the drive system according to the invention
[0054] FIG. 3 shows a longitudinal cross section through a third
embodiment of the drive system according to the invention; and
[0055] FIG. 4 shows a longitudinal cross section through a fourth
embodiment of the drive system according to the invention.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0056] FIG. 1 shows a drive system 10, which is designed in
particular for use in a motor vehicle, preferably in a commercial
vehicle. The drive system 10 has a drive unit 18, which has a drive
shaft 11. By way of the drive shaft 11, which rotates around an
axis of rotation A, the drive unit 18 is connected to a prime mover
(not shown). The prime mover can be, for example, a combustion
machine such as an internal combustion engine or the like. The
torque produced in the prime mover is transmitted via the drive
shaft 11, which can be, for example, a crankshaft, to the adjacent
assemblies of the drive unit 18.
[0057] The drive shaft 11 is also connected to a centrifugal mass
arrangement 70. The centrifugal mass arrangement 70 in the present
example is the flywheel of a clutch 40, which, in the present
example, is designed as a friction clutch.
[0058] The individual assemblies of the drive unit 18 are mounted
in a housing, which, in the present example, consists of several
housing parts. A first housing part 12 is a flywheel bell. Another,
second housing part 13 can be designed as a gearbox bell, for
example, or the like. Between the two housing parts 12, 13, a
spacer element 14 in the form of a spacer ring is provided, which
can be used during the installation of the drive unit 18 in a drive
system 10 to compensate for any length discrepancies which may be
present.
[0059] An electrical machine 30 is mounted inside the flywheel bell
12 between the prime mover (not shown) and the flywheel 70. This
machine functions as a starter-generator. The electrical machine 30
has a rotor arrangement 31 and a stator arrangement 32. The
electrical machine 30 is of the external rotor type, which means
that the rotor arrangement 31 is located farther outward in the
radial direction with respect to the axis of rotation A than the
stator arrangement 32.
[0060] The rotor arrangement 31 is connected to the centrifugal
mass arrangement 70 by a suitable rotor fastening means 33 such as
screws or bolts. In this way, the mass moment of inertia of the
centrifugal mass arrangement 70 is also increased. Radially inside
of the rotor arrangement 31, the stator arrangement 32 is
installed, which is connected to the first housing part 12 by a
stator bracket 34. The connection can be accomplished, for example,
by means of suitable stator fastening means 36 such as screws or
bolts. In the stator arrangement 34, furthermore, a cooling device
35 is provided, which is connected for example, to a cooling system
of the prime mover (not shown). In this way, the stator bracket 34
and thus also the stator arrangement 32 can be cooled in a very
simple and effective manner.
[0061] The clutch 40 in the present case is designed as a friction
clutch and is located inside a clutch housing 41, that is also
referred to as "clutch bell". The clutch housing 41 is connected to
the centrifugal mass arrangement 70 by appropriate fastening means
42 such bolts or screws.
[0062] The clutch 40 also has a clutch pressure plate 43; in the
present exemplary embodiment, the opposing pressure plate is formed
by the centrifugal mass arrangement 70.
[0063] An actuating device 45 actuates the clutch pressure plate
43. For this purpose, the clutch pressure plate 43 is connected by
a diaphragm spring 46 to the actuating device 45 in the manner
known in and of itself.
[0064] A clutch disk arrangement 44 is provided between the clutch
pressure plate 43 and an area of the centrifugal mass arrangement
opposite the pressure plate 43. A torsion damper 60 is also
provided in the clutch disk arrangement 44. The clutch disk
arrangement 44 is connected to the hub 16 of a power takeoff shaft
17. When the clutch 40 is closed, the torque provided by the drive
shaft 11 can be transmitted in the manner known in and of itself
via the clutch disk arrangement 44 to the power takeoff shaft
17.
[0065] To prevent axial misalignments of the stator arrangement 32
and the rotor arrangement 31 until after they have been installed,
these components can be held in place initially by appropriate
fastening means. For example, screws or bolts could connect the
stator arrangement 32 and the rotor arrangement 31 to each other
until they are installed. Assembly fastening means 37 such as bolts
or screws can also connect the stator arrangement 32 to the
centrifugal mass arrangement 70. It is advantageous to remove the
fastening means as soon as the electrical machine 30 has been
installed in the drive system and adjusted.
[0066] So that the space required for the drive unit 18 and thus
for the entire drive system 10 can be kept as small as possible, it
is necessary to create as much room as possible to accommodate the
individual components of the drive unit 18, i.e., of the individual
assemblies of the drive unit 18. In the present exemplary
embodiment, designing the centrifugal mass arrangement 70 in a
special way creates additional room.
[0067] The centrifugal mass arrangement 70 according to FIG. 1
consists, in all, of three areas, i.e., a first area 72, a second
area 73, and a third area 74, which connects the other two areas 72
and 73. The design of the centrifugal mass arrangement 70 is
selected so that the first area 72 serves initially as the
attachment area. The centrifugal mass arrangement 70 is thus
connected to the drive shaft 11 by this attachment area 72. This
can be accomplished by means of suitable fastening means 15 such as
bolts or screws. Radially outside the attachment area 72 with
respect to the axis of rotation there is the second area 73 of the
centrifugal mass arrangement 70, which, in the present case, serves
as the receiving area for the rotor arrangement 31. This receiving
area 73 also serves as the opposing pressure plate for the pressure
plate 43 of the clutch.
[0068] The two areas 72 and 73 are also offset from each other in
the axial direction. The axial offset is again to be understood
with reference to the axis of rotation A. In this way, the
centrifugal mass arrangement 70 has a step-like contour, the height
of the step being determined by the length of the connecting area
74.
[0069] Through the cooperation between the connecting area 74 and
the second area 73, the centrifugal mass arrangement 70 designed in
this way forms a kind of pot, which surrounds the electrical
machine 30. The connecting area 74 and the second area 73 form two
sides of a protected space for the electrical machine 30. The third
and fourth sides of this protected space are formed in the present
example by two sides of the housing part 12. The electrical machine
is thus reliably protected from damage and dirt in the drive unit
18.
[0070] As a result of the special design of the centrifugal mass
arrangement 70, furthermore, a receiving space 71 is created, in
which additional components of the drive unit 18 can be
accommodated. In the present example, the receiving space 71 is
bounded on two sides by the centrifugal mass arrangement 70,
namely, by the first area 72 and by the connecting area 74. With
respect to the axis of rotation A, the receiving space 71 is
located radially inside the electrical machine 30; and in the
exemplary embodiment according to FIG. 1, at least one component of
the clutch 40, among other things, is accommodated in this space.
In the present example, parts of the clutch disk arrangement 44 and
the torsion damper 60 are located in the receiving space 71.
[0071] As a result of the special design of the centrifugal mass
arrangement 70, another space for holding components is created
radially inside the electrical machine 30, so that optimum use can
be made of the available space and the overall axial length (based
on the axis of rotation A) of the drive unit 18 and thus of the
overall drive system 10 can be kept as short as possible.
[0072] FIG. 2 shows a drive unit 18 of a drive system 10, which is
similar in its basic design to the drive unit 18 of FIG. 1. With
respect to the structure and the function of the drive unit 18,
reference can therefore be made initially to the explanations
offered in association with FIG. 1. The same components have been
provided with the same reference numbers.
[0073] The drive unit 18 according to FIG. 2 has a receiving space
71 which is bounded on two sides by the first area 72 and the
connecting area 74 of the centrifugal mass arrangement 70; with
respect to the axis of rotation A and the electrical machine 30,
this space is situated radially inside the machine, and a double
arrangement of torsion dampers 60, 61 is provided in it. Of course,
it is also conceivable that more than two torsion dampers could be
provided in the receiving space 71. All torsion dampers 60, 61 are
connected to the hub 16. For example, the torsion dampers 60, 61
can be connected by a set of external teeth to a large, internally
toothed sleeve, which carries a common cover ring.
[0074] The installation of two or more torsion dampers 60, 61 makes
it possible to provide especially good isolation of the
vibrations.
[0075] FIGS. 3 and 4 show exemplary embodiments of a drive unit 18
for a drive system 10 which have the same assemblies as in the
embodiments according to FIGS. 1 and 2, but in which the assemblies
have been designed and installed differently.
[0076] The drive unit 18 again has a multi-part housing, which, as
in FIGS. 1 and 2, can consist of a first housing part 12 and a
second housing part 13. In contrast to the examples according to
FIGS. 1 and 2, a separate spacer element is not provided in the
exemplary embodiments according to FIGS. 3 and 4. As an
alternative, it would also be possible for the spacer element to be
permanently integrated into one of the two housing parts 12 or
13.
[0077] The drive unit 18 also has a centrifugal mass arrangement
70, except that here its contour differs from that shown in FIGS. 1
and 2. According to FIGS. 3 and 4, the centrifugal mass arrangement
70 consists of two areas 72', 73', which are connected to each
other and which are oriented at an angle to each other. In the
present exemplary embodiment, the centrifugal mass arrangement 70
is designed as a single piece. It is also conceivable, however,
that the two areas 72', 73' of the centrifugal mass arrangement 70
could be produced separately first and then joined to each other to
form the flywheel. This centrifugal mass arrangement 70 is
connected via the first area 72' to the drive shaft 11, which can
be accomplished again by means of appropriate screws or bolts or
the like. The drive shaft 11 rotates around an axis of rotation A,
as also in FIGS. 1 and 2.
[0078] The second area 73' of the centrifugal mass arrangement 70
projects from the first area 72' at a certain angle. In the
examples according to FIGS. 3 and 4, this angle is approximately
90.degree., so that the centrifugal mass arrangement 70 acquires
the approximate shape of an "L".
[0079] As also in FIGS. 1 and 2, an electrical machine 30 in the
exemplary embodiments according to FIGS. 3 and 4 is designed as a
starter-generator and is installed between a prime mover (not
shown) and the centrifugal mass arrangement 70. The electrical
machine 30 is located inside the first housing part 12. The rotor
arrangement 31 of the electrical machine 30 is attached to the
centrifugal mass arrangement 70, i.e., to the second area 73' of
the centrifugal mass arrangement 70, by suitable rotor fastening
means 33. The second area 73' can thus be referred to as a
"receiving area". In contrast, the first area 72' of the
centrifugal mass arrangement 70 can be referred to as an
"attachment area".
[0080] The stator arrangement 32 is attached by a stator bracket 34
to the first housing part 12. This can again be done by the use of
suitable stator fastening means 36. Inside the stator bracket, a
cooling device 35 is provided, by means of which at least the
stator arrangement 32 can be cooled. The cooling device 35 can be
connected to, for example, a cooling device of the prime mover (not
shown).
[0081] As seen from the perspective of the electrical machine 30, a
clutch 40 is provided behind the centrifugal mass arrangement 70.
The clutch 40 has, first, two clutch pressure plates 43, 43'; the
clutch pressure plate 43' is connected to the second area 73' of
the centrifugal mass arrangement 70 by suitable fastening means
such as screws or bolts.
[0082] The clutch 40 has a clutch disk arrangement 44, which is
connected to the hub 16 of a power takeoff shaft. A torsion damper
60 is also integrated into the clutch disk arrangement 44.
[0083] As also in the exemplary embodiments according to FIGS. 1
and 2, the centrifugal mass arrangement 70 is also designed in the
exemplary embodiments according to FIGS. 3 and 4 in such a way that
it creates a receiving space 71 radially inside the electrical
machine 30, this receiving space 71 being bounded on at least one
side by the centrifugal mass arrangement 70. According to the
examples of FIGS. 3 and 4, the receiving space 71 is bounded on two
sides by the centrifugal mass arrangement 70 via the two areas 72',
73' of the centrifugal mass arrangement 70. A third side of the
receiving space 71 is bounded by the stator bracket 34.
[0084] Certain components of the clutch 40 are installed inside the
receiving space 71 and thus in front of the centrifugal mass
arrangement 70. First, the actuating device 45 of the clutch is
mounted in the receiving space 71. This actuating device 45
consists of an actuator 47 mounted in a cylinder 48. The actuator
47 actuates a diaphragm spring 46, at least part of which is also
located in the receiving space 71. The diaphragm spring 46 is
therefore situated in front of the centrifugal mass arrangement 70,
on the side facing the prime mover. The actuator 47 can be, for
example, a concentric pneumatic actuator.
[0085] Because of the way in which the drive unit 18 is designed,
the size of the drive unit 18 can be made very small in the axial
direction (relative to the axis of rotation A).
[0086] So that the clutch pressure plate 43 can be actuated
properly, through-openings 75, 76 are provided in the second area
73' of the centrifugal mass arrangement 70, through which openings
the diaphragm spring 46 can make contact with the clutch pressure
plate 43. The actuating device 45 can thus perform its function
properly via the diaphragm spring 46.
[0087] FIG. 4, finally, shows an embodiment of a drive unit 18 for
a drive system 10, which is approximately the same as that
according to FIG. 3. For this reason, reference can be made
initially to the explanations of the basic design and function
offered in regard to FIG. 3. The same components are again provided
with the same reference numbers.
[0088] The embodiment according to FIG. 4 differs from the design
variant shown in FIG. 3 in that the actuating device 45, comprising
an actuator 47, no longer has its own independent cylinder 48.
Instead, the cylinder 48 is formed by the surface 38 of the stator
bracket 34 which is on the inside, as seen from the perspective of
the axis of rotation A. The inside surface 38 of the stator bracket
34 thus serves simultaneously as the cylinder for the actuator 47,
which can be, for example, a concentric, pneumatic actuator.
[0089] In comparison with the design variant shown in FIG. 3, the
cylinder of the actuator 47 is eliminated in the embodiment
according to FIG. 4. This leads among other things to a further
reduction in the amount of space required. In addition, the
actuator 47 can be easily cooled efficiently, because it can be
cooled simultaneously by the cooling device 35 that cools the
stator bracket 34.
[0090] The goal achieved by the present invention is that optimum
use can be made of the space available inside the drive unit 18, so
that the overall axial length of the drive unit 18 in relationship
to the axis of rotation A can be kept as short as possible.
[0091] Thus, while there have shown and described and pointed out
fundamental novel features of the invention as applied to a
preferred embodiment thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
the devices illustrated, and in their operation, may be made by
those skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps which perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
and/or method steps shown and/or described in connection with any
disclosed form or embodiment of the invention may be incorporated
in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention,
therefore, to be limited only as indicated by the scope of the
claims appended hereto.
* * * * *