Note: Descriptions are shown in the official language in which they were submitted.
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FOUR WHEEL DRIVE HYBRID VEHICLE
The invention relates to a two-axle motor vehicle in accordance
with the precharacterizing clause of Claim 1.
Such two-axle motor vehicles, which are conventionally driven
via an internal combustion engine and have permanent all-wheel
i 10 drive, are state-of-the-art and are sold by the Applicant under
~;3 the trademark "Quattro".
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Hybrid vehicles, which can be driven both via an internal
l; co~bustion engine as well as via an electric motor, are known,
R~ 15 for the purpose of meeting existing or proposed legal
requirements. The usual procedure is to have either the
i! internal combustion engine or the electric motor act on a dri~en
$ axle or to assign the internal combustion engine ~o one axle and
the electric motQr to the other axle (see DE-A 39 40 172). A
review of the state of development of electric and hybrid
vehicles is provided by A. Gahleitner, Stand der Entwicklung von
Elektro-StraBenfahrzeugen, OZE, Vol. 42, No. 5, p. 179 ff.
This requires a relatively involved drive concept.
The object of the invention is to reduce the outlay for the
drive concept.
According to the invention, thls can be achieved in a motor
vehicle of generic type by combining the electric motor with the
propeller shaft. This solution offers the advantage that the
permanent all-wheel drive already available is also retained in
the electric-motor type of operation. However, the advantages
are even more pronounced if the electric motor can also be
connected up as a generator in order to recover electrical
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energy from the mechanical energy during braking or in overrun
mode, e.g. when running downhill. In the arrangement of the
present invention, during recovery mode all four wheels are
-acted upon simultaneously by braking force, and as a result
~'5 uncontrolled operation, particularly on slippery roads, does not
occur, rather braking action occurs in a conventional and
familiar manner. Prior art vehicles were in this case only
capable of braking two wheels, which can lead to dangerous
operating conditions.
~ 10
The avoidance of viscous couplings makes it possible to retain
-the output both to the front and rear.
According to the present invention, it is advantageous to use a
permanent-magnet synchronous motor, in this case one section of
the propshaft providing the rotor, the propshaft merely being
provided with permanent magnets, which are preferably glued on.
An additional tape affixes the magnets. Surrounded by the
stator windings, a small constructional unit is achieved. The
speed of rotation of the propshaft is designed so that, even at
maximum speed, the permissible speed of rotation for the
electric motor (about 10,000 revolutions/ minute) is not
exceeded. This advantage is difficult to achieve in the case of
other motors without appropriate gearing, since the rotor
windings cannot withstand such high speeds of rotation.
This makes is possible to combine the electric motor and the
rear-axle differential to form a single constructional unit, so
that the electric motor can be arranged in a manner which saves
space and allows favorable weight distribution in the vehicle.
As follows, the invention is described with reference to the
drawing. There is shown~
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Fig. 1 a side view illustrating the installation
position;
Fig. 2 a section through the electric motor.
Reference numeral 10 shows a hybrid vehicle which, in the region
of the front wheels 18, has an internal combustion engine 16 and
an adjoining gearbox 12. At the gearbox output there is an
intermediate differential, via which, on the one hand, a drive
shaft a~ts on the front wheels 18, and by which, via a propshaft
20 and a rear-axle differential 14, the rear wheels 22 are
~ driven.
! In addition, there is provided an electric motor 24, which is
supplied with ele~trical energy by means of a set 26 of
batteries and which can drive the propshaft.
The construction of the electric motor is shown in detail in
;~ Fig. 2. The electric motor has a rotor or runner 32 and a
stander or stator 34, the stator 34 being formed by individual
windings with corresponding winding overhangs 36.
The rotor 32 forms thereby part of the propshaft 20 and is
connected directly to it by a flange 44. The outside of the
rotor 32 has permanent magnets 38 bonded to it. An air gap 40
is provided between the taped permanent magnets 38 and the
stator 34. A housing 42 surrounds the construction.
In area 46, opposite the end 44 with the flanged-on propshaft
20, the electric motor 24 is connected directly to the rear-axle
differential 14.
Through the design of the electric motor as permanent-magnet
~3 synchronous motor, a speed of revolution of the rotor 32 of up
to 10,000 revollltions per minute is possible, so that also in
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:l the case of high-speed vehicles a continuous running of the
motor 24 is possible, without the motor being damaged.
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