Planetary gear transmission systems or components – Planetary gearing or element – Floating or flexible coupling or support
Reexamination Certificate
1999-08-25
2001-05-15
Bonck, Rodney H. (Department: 3681)
Planetary gear transmission systems or components
Planetary gearing or element
Floating or flexible coupling or support
C192S003280
Reexamination Certificate
active
06231472
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to a torsional vibration damper in a lockup clutch of a hydrodynamic clutch device having an impeller wheel and a turbine wheel, wherein the torsional vibration damper is connected between a turbine shell and a turbine hub of the turbine wheel and includes a drive side damper element connected with the turbine shell, a driven side damper element connected to the turbine hub, and a circumferentially acting spring connected between the drive-side and driven-side damper elements.
2. Description of the Related Art
A prior art torsional vibration damper arranged between a turbine shell and a turbine hub of a turbine wheel is known, for example, from German reference DE 43 33 562 A1. This reference discloses a clutch device constructed with an impeller wheel, a turbine wheel having a turbine shell, and a stator wheel and accordingly acts as a hydrodynamic torque converter. The turbine shell is arranged so as to be rotatable relative to a turbine hub and is connected with a drive-side damper element of the torsional vibration damper. The drive-side damper element is operatively connected with a driven-side damper element via a damping device with energy accumulators acting in the circumferential direction. The radial inner side of the driven-side damper element is fixed with respect to rotation relative to the turbine hub so as to be fixed with respect to rotation relative to it.
Considered as a free oscillating system, the drivetrain of a motor vehicle may be roughly reduced to six masses. It is assumed that the drive, including the impeller wheel, is the first mass, the turbine wheel is the second mass, the transmission input shaft is the third mass, the cardan shaft (including the universal joint, i.e., cardan joint) and differential are the fourth mass, the wheels are the fifth mass and the vehicle overall is the sixth mass. In a free oscillating system with n masses (in this case n=six), it is known that n resonant frequencies occur. However, the first resonant frequency relates to the rotation of the entire oscillating system and is not relevant to vibration damping. The rates of rotation or speeds at which the resonant frequencies are excited depend on the number of cylinders of the drive which is constructed as an internal combustion engine.
Because the drive-side damper element of the torsional vibration damper acts on the turbine shell and the driven-side damper element acts on the driven shaft which, as is known, acts as a transmission input shaft, the torsional vibration damper according to the above-cited DE 43 33 562 A1 is commonly known in technical circles as a “turbine damper” and has the following characteristics:
Because the driven-side transmission element is directly connected with the transmission input shaft, the damping device which connects this damper element with the drive-side damper element acts as if it were connected in series with the elasticity of the transmission input shaft, which elasticity is conditional upon torsion. However, since the stiffness of the energy accumulators of the damping device is much less than that of the transmission input shaft, the transmission input shaft is considered very soft with respect to total rigidity. This softness of the transmission input shaft results in excellent decoupling characteristics.
With respect to the resonant frequencies in the drivetrain, the extensive softness of the transmission input shaft causes the third and fourth resonant frequencies of the five resonant frequencies mentioned above to have greater amplitudes compared to a torsional vibration damper arranged in conventional manner between the piston and turbine hub. However, the third resonant frequency occurs at considerably lower speeds, namely at a speed in the order of magnitude of the second resonant frequency. Accordingly, the third resonant frequency has practically no effect when the lockup clutch is closed already at a very low speed, for example, 1200 RPM. However, no influence can be exerted in this way on the fourth resonant frequency, so that noise may occur when passing through the speed range associated with this resonant frequency.
SUMMARY OF THE INVENTION
It is the object of the invention to develop a torsional vibration damper for a lockup clutch of a hydrodynamic torque converter in such a way that as few resonant frequencies as possible, with the smallest possible amplitudes, can develop above the frequency range associated with a very low closing speed of the lockup clutch.
This object is met, according to the invention, through a torsional vibration damper in a combination with a lockup clutch in a hydrodynamic clutch device including an impeller wheel and a turbine wheel having a turbine shell and a turbine hub. The torsional vibration damper comprises a drive-side damper element connectable with the turbine shell of the turbine wheel and rotatable about an axis of rotation, a driven-side damper element connectable with the turbine hub of the turbine wheel and rotatable about the axis of rotation, a damping device comprising at least one energy accumulator arranged circumferentially between the driven-side damper element and the drive-side element such that the drive-side element is rotatable relative to the driven side element against a circumferential force of the energy accumulator, and a planetary gear set comprising a carrier for at least a first gear unit element, the carrier being operatively connected with a first component comprising one of a first damper element and a component connected to the first damper element, and a second gear unit element operatively connected with a second component comprising one of a second damper element and a component connected to the second damper element, wherein the first damper element comprises one of the drive-side damper element and the driven-side damper element and the second damper element comprises the other one of the drive-side element and the driven-side element.
A planetary gear set is used, wherein the drive-side damper element of the torsional vibration damper is constructed as a planetary carrier at which at least one planet gear is rotatably received. The planet gear drives a sun gear which forms the driven-side damper element. In response to the operation of the planetary gear set, in this case especially with respect to the gear unit masses additionally introduced through the gear elements of the planetary gear set, there is generated a mass matrix M given by the following formula:
M
=
[
J
t
*
+
4
(
i
+
1
)
2
·
J
p
+
(
i
+
1
)
2
i
2
·
J
h
-
4
(
i
+
1
)
2
·
J
p
+
i
-
1
i
2
·
J
h
-
4
(
i
+
1
)
2
·
J
p
+
i
-
1
i
2
·
J
h
J
S
+
4
(
i
+
1
)
2
·
J
p
+
i
-
1
i
2
·
J
h
]
,
where
i
=
-
r
H
r
S
J
t
*
=
J
t
+
m
p
·
a
2
.
The symbols contained in the formula indicated above are defined as follows:
J
t
mass moment of inertia of planetary carrier
J
s
mass moment of inertia of sun gear
J
h
mass moment of inertia of ring gear
J
p
mass moment of inertia of planet gear
m
p
mass of planet gear
a axial distance (axis of rotation to center axis of planet gear)
The parts of the formula between the brackets at upper left and lower right form the main diagonal of the mass matrix, while the parts at lower left and upper right form the secondary diagonal of the mass matrix. The main diagonal indicates the resonant frequency of the torsional vibration damper by the mass moments of inertia and transmission ratios indicated therein. Of course, the stiffness given by the energy accumulator is also indicated, wherein the stiffness matrix is given as:
c
=
c
′
[
1
-
1
-
1
1
]
,
where c′ is the spring constant of the energy accumulator.
The secondary diagonal of the mass matrix gives the “negative resonant frequency” of the torsional vibration damper, the optimum decoupling frequency, a frequency at which a minimum is achieved in the ampl
Sasse Christoph
Sudau Jorg
Wack Erwin
Bonck Rodney H.
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
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