Note: Descriptions are shown in the official language in which they were submitted.
The invention relates to a drive means for an ~lec-
trical vehicle having a motor arranged stationarily in the
bpgey or main chassis of the vehicle. The motor acts,
through a torsionally resilient coupling, upon the wheels of
the vehicle, through a transmission, accommodated in a gearbox
and consisting of a crown gear and a pinion.
Drives for electrical vehicles must meet the following
requirements: in particular they must:
~ be able to transmit high power and torque;
- permit all components of movement of the wheels
of the vehicle, in most cases with only minor restoring forces,
- provide a specific amount of torsional resiliency;
for example, they must be capable of ab~orbing stalling-torque
: shocks from asynchronous motors,
- maintain the best possible angular correctness, this
means that when the wheels are deflected by steering, the
rotational movement of the motor shaft must be very smalL,
- provi.de a minimum of unsprung weight; a minimum of
additional mass (motor and drive components) is to be coupled
directly to the vehicle wheels.
In addition to the foregoing, the drive ~hould exhibit
little wear, should require only simple maintenance, and should
require overhaul only at infre~uent intervals. It should be a
simple matter to install the motor and the drive in the chassis,
and to remove them therefrom~
In one drive means disclosed in the book "Elektrische
~ri~bfahrzeuge", by Karl Sachs, Springer~Verlag, Wien, New York,
2nd. Edition 1973, Vol. 1, pages 438 to 440, more particularly
paragraph 3.312 on page 439, the pinion and crown gear are
arranged in a two-piece, torsion-resistant gearbox support~d with
5775
roller bearings upon the wheel axle. At the pinion end, the
gearbox is mounted in two spherical rubber elements concentric
with the motor shaft, the said rubber elements being accomo-
dated in turn in a forked carrier secured to the bogey.
In the case of another known drive means (loc. cit.,
page 4~7, more particularly paragraph 3.321) referred to in
the relevant literature as rubber-hinge cardan drive - the
unit absorbing relative motion between the vehicle and the
bogey is built around the wheel axle and consists, in principle,
of two central articulated-lever couplings united by means of
a hollow shaft. While one element absorbs the torque from the
transmission, the other transmits it to the vehicle wheels.
If torsional resiliency i~s required3 one of the articulated-
lever couplings is replaced by an annular rubber spring~
Both of these known drive means have given sa-tisfac-
tory results in a large number o~ electrical vehicles.
However, the cons-tant increase in drive-power and top
speeds, and the simultaneous reduction of the load on rail
elements9 requires drives which must satisfy optimally, and in
all respects, the requirements mentioned at the beginning
hereof~
It is therefore the purpose of the invention to
provide a drive means of the type mentioned at the beginning
hereof 9 which will be able to meet the above-mentioned re~uire-
ments to the fullest possible degree, but which will be simple
and economical to build and maintain.
In accordance with the invention, there is provided a
drive means for an electrical vehicle, which comprises a motor
arranged stationarily in a bogey or main chassis of the vehicle
and including a motor sha~t, a transmission supported in a gear-
box and including a crown gear and a pinion, the gearbo~ being
arrang~d sta-tionarily in the , gey or main chassis, a torsional-
~577~
ly resilient coupling connecting the motor shaft to the pinionand a hollow cardan shaft connecting the crown gear to the
wheels of the vehicle, wherein the torsionally resilient coupl-
ing is a rubber coupling comprising two conical discs with a
drive disc therebetween, the conical discs being connected to
the motor shaft and the drive disc to the pinion, and rubber
elements arranged between the conical discs and the drive disc
and vulcanized to both the conical discs and the drive disc.
The design of the drive means according to the inven-
tion distributes different functions to different components,as required in an optimal technical layout~ since the coupling
arranged between the motor and the transmission provides the
necessary torsional resiliency and compensates for any mala-
lignment between the motor and the pinion shaft, while the
hollow cardan shaft permits three-dimensional movement of the
vehicle wheels almost free of restor.ing torque. In addition
to this~ the fact that the gearbox is secured to the bogey or
main chassis reduces unsprung weight to a minimum.
The ends of the hollow cardan shaft are connected to
the crown gear and to the vehicle-wheel axle, preferably through
a central articulated-lever coupling. Known components of this
kind, disclosed for example in Figs. 4 and 5 of Swiss Patent
436,~69 and in paragraph 3.322 on page 488 of the reference
"Elektrische Triebfahrzeuge" mentioned above, tran~fer the
entire power-plant torque, they centre the hollow cardan shaft
without producing out-of-balance or inertia forces, they permit
angular movement of the cardan shaft without producing internal
resistance tor~ue, they are sufficiently resilient, axially
to compen~ate for assembly inaccuracies, and they also permit
lateral movement of the vehicle wheels.
The torsionally resilient coupling between the motor
~ 3 ~
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shaft and the pinion is in the form of a rubber coupling, as
set forth in paragraph 3.312 on page 439 of the above-mentioned
reference.
This coupling consists essentially of two conical
discs with a drive disc therebetween, all united resiliently
by vulcanizing with rubber. The conical discs are attached to
the motor shaft, whereas the drive disc is attached to a flange
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at the end of the pinion shaft. The resiliency of this ru~ber
coupling may be varied over a wide ranye by the choice of the
mixture from which the rubber element is made and of the
geometry of the said elemen-t. Torsional resiliency may also
be adjusted by means of suitable clamping elements which press
the two conical discs together. Since both the motor and the
gearbox are secured stationarily in the bogey or main chassis
of the vehicle, the rubber coupling is subjected to scarcely
any additional deformation. However, the said coupling com-
pensates, in a simple manner, for malalignment between themotor and pinion shafts and provides the necessary torsional
resiliency between the motor and the crown gear.
The invention is explained hereinafter in greater
detail, in conjunction with the example of embodiment illustrated
in the drawing attached hereto.
In this drawing, a motor 1 having a shaft 2 is secured
to bogey 3. Secured to motor shaft 2 is a rubber coupling 4
consisting of two conical discs 5 and 6 with a drive disc 7
therebetween. Annular rubber elements 8 and 9 are vulcanized
to the opposing surfaces of the said conical discs and to both
sides of the drive disc. Discs 5 and 6 are held together by
clamping means, e.g. bolts, not shown in detail but indicatPd
by pairs o~ arrows 10 and 11. Drive disc 7 is secured to the
~langed end 12 of the shaft of a pinion 14 mounted in a torsion-
resistant gearbox 13 secured to bogey 3. Pinion 14 meshes with
a-crown gear 15 also mounted in gearbox 13. Bearings 16 and 17
for pinion 14 and crown gear 15 are illustrated only diagram-
matically in the drawing. Crown gear 15 is connected, by a first
articulated-lever coupling 18, to one end of hollow cardan shaft
20 surrounding wheel axle 19, the other end of the said cardan
7~
shaft being connected, through a second articulated-lever
coupling 21, to the hub of vehicle wheel 22.
Rubber coupling 4 provides a torsionally resilient
connection between motor shaft 2 and pinion 14. It also
serves to provide a considerable amount of torque-pulsation
damping and to compensate for any malalignment between motor
shaft 2 and the shaft of pinion 14. Hollow cardan shaft 20,
with its articulated-lever couplings 18 and 21 centred at both
ends, which connects crown gear 15 and wheel axle 19, allows
for three-dimensional movement of the vehicle wheels almost free
of any restoring force~
In the drive means according to the invention, in
contrast to existing drives, the components providing torsional
resiliency and guidance for the vehicle wheels are separated from
each other structurally and spatially, thus making it possible
for the dimensions of each component to be adapted to the functions
it performs.
The rigid connection between motor 1 and bogey 3
and between the latter and gearbox 13, provides a minimum of
unsprung weight, in contrast to other drive designs.
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