U.S. patent application number 09/784725 was filed with the patent office on 2002-08-15 for active decoupler hydraulic mount.
Invention is credited to Baudendistel, Thomas A., Dingle, James E., Foister, Robert T., Long, Mark W., Tewani, Sanjiv G..
Application Number | 20020109280 09/784725 |
Document ID | / |
Family ID | 25133333 |
Filed Date | 2002-08-15 |
United States Patent
Application |
20020109280 |
Kind Code |
A1 |
Baudendistel, Thomas A. ; et
al. |
August 15, 2002 |
ACTIVE DECOUPLER HYDRAULIC MOUNT
Abstract
A hydraulic mount for an automotive vehicle or machine includes
opposed mounting members secured to an elastomeric body and a base,
respectively. An orifice plate assembly is interposed the body and
the base to define a pumping chamber and a reservoir for fluid to
flow therebetween through an orifice track of the orifice plate
assembly. An electroactive polymer decoupler member is secured in a
cavity formed between two orifice plates of the orifice plate
assembly. The decoupler member is operably connected to a
controller for imposing an electric field on the decoupler member
to change its shape and thereby selectively vary the dynamic
stiffness of the mount.
Inventors: |
Baudendistel, Thomas A.;
(Farmersville, OH) ; Tewani, Sanjiv G.; (Lebanon,
OH) ; Long, Mark W.; (Bellbrook, OH) ; Dingle,
James E.; (Cincinnati, OH) ; Foister, Robert T.;
(Rochester Hills, MI) |
Correspondence
Address: |
Scott A. McBain
Delphi Technologies, Inc.
P.O. Box 5052
Mail Code: 480-414-420
Troy
MI
48007-5052
US
|
Family ID: |
25133333 |
Appl. No.: |
09/784725 |
Filed: |
February 15, 2001 |
Current U.S.
Class: |
267/140.15 ;
267/140.14 |
Current CPC
Class: |
F16F 13/268 20130101;
F16F 13/106 20130101; F16F 13/26 20130101 |
Class at
Publication: |
267/140.15 ;
267/140.14 |
International
Class: |
F16F 009/00 |
Claims
What is claimed is:
1. A hydraulic mount for an operating component of a vehicle
comprising: first and second mounting members; a body connected to
one of the mounting members and a base connected to the other of
the mounting members; a partition interposed said body and said
base; a fluid pumping chamber formed between said body and said
partition and a fluid reservoir formed between said partition and a
member interposed said partition and said base; a cavity in said
partition; and a decoupler member supported in said cavity and in
fluid communication with at least one of said pumping chamber and
said reservoir, said decoupler member being formed of an
electroactive polymer and adapted to be connected to a source of
electric potential for changing the configuration of said decoupler
member.
2. The mount set forth in claim 1 wherein: said partition comprises
an orifice plate assembly including an orifice track formed therein
for transferring fluid between said pumping chamber and said
reservoir.
3. The mount set forth in claim 2 wherein: said member interposed
said orifice plate assembly and said base comprises a flexible
diaphragm delimiting said reservoir.
4. The mount set forth in claim 2 wherein: said orifice plate
assembly includes a first orifice plate including a plurality of
openings formed therein for providing fluid communication between
said pumping chamber and said decoupler member.
5. The mount set forth in claim 4 wherein: said orifice plate
assembly includes a second orifice plate including a plurality of
openings therein for providing fluid communication between said
reservoir and said decoupler member and said cavity is formed
between said orifice plates.
6. The mount set forth in claim 5 wherein: said decoupler is
secured in fluid tight sealing engagement around a periphery of
said decoupler member between said orifice plates.
7. The mount set forth in claim 1 including: conductor means
connected to spaced apart electrodes of said decoupler member and a
controller operably connected to said conductor means for imposing
an electric field on said decoupler member.
8. The mount set forth in claim 7 wherein: said controller is
operably connected to a sensor for sensing vibrations of a
structure supported by said mount.
9. The mount set forth in claim 7 wherein: said controller is
operably connected to a speed sensor for sensing a rotational speed
of an engine whose vibrations are to be damped by said mount.
10. The mount set forth in claim 1 wherein: said decoupler is
formed of a material selected from a group consisting of
polyacrylonitrile, polyvinyl-chloride, silicone rubber and electric
conductive polymers.
11. A hydraulic mount for an operating component of a vehicle
comprising: first and second mounting members; a body connected to
one of the mounting members and a base connected to the other of
the mounting members; a partition interposed said body and said
base and defining a cavity, said partition including an orifice
track formed therein for transferring fluid between a fluid pumping
chamber and a fluid reservoir of said mount; and a decoupler member
supported in said cavity and in fluid communication with at least
one of said pumping chamber and said reservoir, said decoupler
member being formed of an electroactive polymer, and adapted to be
operably connected to a source of electric potential for
selectively changing the configuration of said decoupler member to
vary the dynamic stiffness of said mount.
12. The mount set forth in claim 11 wherein: said partition
comprises an orifice plate assembly comprising a first orifice
plate including a plurality of openings formed therein for
providing fluid communication between said pumping chamber and said
decoupler member.
13. The mount set forth in claim 12 wherein: said orifice plate
assembly includes a second orifice plate including a plurality of
openings therein for providing fluid communication between said
reservoir and said decoupler member.
14. The mount set forth in claim 13 wherein: said cavity is formed
between said orifice plates.
15. The mount set forth in claim 14 wherein: said decoupler member
is secured in fluid tight sealing engagement around a periphery of
said decoupler member between said orifice plates.
16. The mount set forth in claim 11 including: conductor means
connected to respective electrodes of said decoupler member and a
controller operably connected to said conductor means and a source
of electric power for imposing an electric field on said decoupler
member at a selected frequency to effect deflection of said
decoupler member in such a way as to modify the dynamic stiffness
of said mount.
17. The mount set forth in claim 16 wherein: said controller is
operably connected to a sensor for sensing vibrations of a
structure supported by said mount.
18. The mount set forth in claim 16 wherein: said controller is
operably connected to a speed sensor for sensing a rotational speed
of an engine whose vibrations are to be damped by said mount.
19. A hydraulic mount for an operating component of a vehicle
comprising: first and second mounting members; a body connected to
one of the mounting members and a base connected to the other of
the mounting members; a partition interposed said body and said
base and defining a cavity, said partition comprises an orifice
plate assembly including a first orifice plate and having a
plurality of openings formed therein for providing fluid
communication between said pumping chamber and said cavity and a
second orifice plate including a plurality of openings therein for
providing fluid communication between said reservoir and said
cavity; a decoupler member supported in said cavity and in fluid
communication with said pumping chamber and said reservoir, said
decoupler member being formed of an electroactive polymer, and
adapted to be operably connected to a source of electric potential
for selectively changing the configuration of said decoupler member
to vary the dynamic stiffness of said mount; conductor means
connected to respective electrodes of said decoupler member; and a
controller operably connected to said conductor means and a source
of electric power for imposing an electric field on said decoupler
member at a selected frequency to effect deflection of said
decoupler member in such a way as to modify the dynamic stiffness
of said mount.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to a hydraulic mount,
particularly adapted for automotive powertrain applications, which
includes a decoupler member formed of an electroactive polymer
whereby the configuration of the decoupler may be modified to
modify the dynamic stiffness and damping characteristics of the
mount.
BACKGROUND
[0002] Hydraulic type vibration damping mounts have been developed
which are particularly adapted for automotive powertrain support
applications. One type of hydraulic mount includes a decoupler
member which is operable to undergo relatively free limited motion
in phase with the input vibrations to the mount to provide low
dynamic stiffness of the mount to thereby effectively isolate
relatively low amplitude vibrations.
[0003] Conventional decoupled hydraulic mounts are normally
designed such that the passive decoupler has a resonance frequency
in a particular range. Conventional hydraulic mounts with passive
decouplers typically resonate in the 100 Hertz to 300 Hertz
frequency range, for example, and the dynamic stiffness of the
mount increases substantially in frequency ranges above the
resonance frequency of the decoupler, since the motion of the
decoupler is not able to compensate for the volumetric change of
the fluid pumping chamber of the mount. Accordingly, reduced
isolation of vibrations above the resonant frequency range of the
decoupler is experienced and high frequency engine generated
vibrations, for example, are typically transmitted to the vehicle
body structure.
[0004] The vibration isolation characteristics of a hydraulic mount
can be varied by imposing certain forces on the decoupler. For
example, an air cushion or air "spring" comprising a trapped volume
of air between the decoupler and a partition plate can change the
damping characteristics of the mount. However, if the motion of the
decoupler can be more actively and accurately controlled, the
effective dynamic stiffness of the mount can be further reduced at
selected frequencies and better isolation characteristics can be
obtained for powertrain mounts used in automotive vehicle
applications, in particular. For example, it may be desired to
control the motion of the decoupler as a function of engine speed
(crankshaft revolutions per minute or rpm) such that the vibration
isolation characteristics of the mount are achieved in one or more
frequency ranges of vibrations related to engine speed and which
would be typically input to the mount. It is to these ends that the
present invention has been developed.
SUMMARY OF THE INVENTION
[0005] The present invention provides an improved hydraulic mount,
particularly adapted for automotive vehicle engine and related
powertrain applications.
[0006] In accordance of one important aspect of the invention, a
hydraulic engine or powertrain mount is provided which includes an
active decoupler and which has a dynamic stiffness which may be
substantially lower than the static stiffness of the mount.
Moreover, the dynamic stiffness of the mount may be variably
"tuned" to vehicle engine speed, for example, such that the mount
provides good vibration isolation between the engine and the
vehicle body.
[0007] In accordance with another aspect of the invention, a
hydraulic mount with an active decoupler is provided wherein the
decoupler shape or motion may be controlled in accordance with a
particular vibration disturbance acting on the hydraulic mount. In
particular, the decoupler is preferably formed of an electroactive
polymer material whose shape and/or volume may be changed as a
function of imposing an electric field on the decoupler.
Accordingly, the decoupler may be actuated such that it is
deflected or moved as a function of the vibrations input to the
mount and as a consequence the decoupler may influence the dynamic
stiffness characteristics of the mount. The mount may be controlled
such that a very low magnitude of mount dynamic stiffness is
provided at selected vibration frequencies normally imposed on the
mount. Under other operating conditions, such as when the vehicle
is in motion or under hard acceleration, the decoupler may be
configured such as to force hydraulic fluid in the mount to flow
through an orifice or orifice track to provide a higher mount
dynamic stiffness and damping characteristics which can be used to
control or limit the motion of the vehicle powertrain.
[0008] In accordance with yet another aspect of the present
invention, an active decoupler hydraulic mount is provided which is
operable to satisfy substantially all of the requirements for
static stiffness, vibration isolation and dynamic stiffness of the
mount for all operating characteristics of a vehicle associated
with the mount.
[0009] Those skilled in the art will further appreciate the
advantages and superior features of the invention together with
other important aspects thereof upon reading the detailed
description which follows in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIG. 1 is a longitudinal central section view, in somewhat
schematic form, of an active decoupler hydraulic mount in
accordance with the invention; and
[0011] FIG. 2 is a diagram of dynamic stiffness versus frequency
showing a typical operating characteristic for an actively
controlled mount in accordance with the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0012] In the description which follows, like parts are marked
throughout the specification and drawing with the same reference
numerals, respectively. The drawing figures are not necessarily to
scale in the interest of clarity and conciseness.
[0013] Referring to FIG. 1, there is illustrated in somewhat
schematic form a hydraulic mount adapted for vehicle applications,
such as an engine or other powertrain component mount, and
generally designated by the numeral 10. The mount 10 includes a
substantially frustoconical shaped elastomer body 12 suitably
molded to a mounting member 14 having an upward projecting threaded
post 16. The mount 10 is also characterized by a generally
cylindrical plate-like partition 18 comprising an orifice plate
assembly including opposed orifice plates 20 and 22 which are
suitably joined to provide at least a partial annular passage 24
formed therebetween. The passage 24, otherwise known as a so-called
orifice track, is in communication with fluid transfer ports 26 and
28 which may be circumferentially spaced along the track 24 in such
a way as to provide a predetermined path length for transfer of
fluid between a pumping chamber 30 and a reservoir 32.
[0014] Reservoir 32 is defined in part by the orifice plate
assembly 18 and a flexible elastomer diaphragm 34 disposed in a
somewhat cylindrical can shaped base plate 36. A second mounting
member 38 is suitably secured to the base plate 36 for connecting
the mount 10 to a vehicle body structure, not shown. Accordingly,
the mounting member 16 may be connected to the vehicle engine or
other powertrain component for supporting same relative to the
aforementioned vehicle body structure. As shown in FIG. 1, the
elastomer body 12, the partition 18, the diaphragm 34 and the base
plate 36 may be secured in fluid tight assembly with each other by
a suitable annular band 40. The manner of securing the mount
components in assembly is exemplary and other means known to those
skilled in the art may be used to secure the components
together.
[0015] Referring further to FIG. 1, the partition 18 includes a
generally cylindrical shallow cavity 42 formed by cylindrical
recessed wall parts 21 and 23 formed in the orifice plates 20 and
22. Plural fluid transfer ports 25 and 27 open into the cavity 42
from the pumping chamber 30 and from the reservoir 32,
respectively.
[0016] The cavity 42 between the plates 20 and 22 is at least
partially filled with a generally cylindrical disk-shaped decoupler
member 46 having a peripheral circumferential flange 48 formed
thereon and clamped between the orifice plates 20 and 22 of the
orifice plate assembly or partition 18 in substantially fluid tight
engagement to prevent fluid leakage across the decoupler member 46
between the pumping chamber 30 and the reservoir 32. The decoupler
46 is formed of an electroactive polymer which may be selected from
one of a type described further herein. The decoupler member 46 is
also characterized by suitable electrodes 50 and 52, shown spaced
apart from each other and embedded in the decoupler member. The
electrodes 50 and 52 are connected, respectively, to suitable
conductors 54 and 56 leading to a controller 58. Conductors 54 and
56 are shown encapsulated in a sleeve 60 which penetrates the
elastomer body 12 but forms a fluid tight seal between the pumping
chamber 30 and the exterior of the mount 10. Other arrangements of
conductor members or leads connected to the electrodes 50 and 52
may be provided.
[0017] Controller 58 is suitably connected to an electrical power
supply 64 and may also be connected to a suitable engine crankshaft
speed (rpm) sensor 66 and/or a suitable vibration sensor 68, both
operable, if desired, to provide input signals to the controller to
cause the controller to apply a selectively controlled voltage
across the electrodes 50 and 52. The decoupler member 46 comprises
a suitable electroactive polymer, such as polyacrylonitrile, or
other suitable ion exchange polymers selected from a group
consisting of polyvinyl-chloride, silicone rubber and similar
conducting polymers. Moreover, the configuration of the decoupler
member 46 may be varied and may be, for example, such as to provide
a layered construction of elastomer films sandwiched between
compliant electrodes, such as the electrodes 50 and 52. The
electrodes 50 and 52 may be a thin film of highly conductive
material or a conductive grease layer, for example. In all events,
when a voltage is applied across the electrodes 50 and 52, the
shape of the decoupler member 46 may be changed in a selected
manner.
[0018] For example, when an electric potential is applied across
the electrodes 50 and 52, the decoupler member 46 may change its
shape in such a way as to provide for motion or deflection within
the space 42 toward wall part 21 and away from wall part 23 or vice
versa. The amount of deflection may be controlled by varying the
electric potential imposed on the decoupler in relation to engine
speed or vibrations sensed by the sensors 66 and 68. The decoupler
member 46 may be forced to move in the aforementioned space 42 as a
function of a vibration disturbance input to the mount 10 such that
the resistance to the motion of the mount is substantially reduced.
Consequently, the effective dynamic stiffness of the mount 10 may
be reduced and in turn provide good isolation for low amplitude
higher frequency vibrations. For example, with an unbalanced engine
running at idle conditions or during smooth road cruise conditions,
when good isolation is required from the engine mounts to reduce
the noise transmitted from the engine to the passenger compartment,
the decoupler 46 may be activated by the controller 58 as a
function of the vibrations at selected frequencies to be
isolated.
[0019] However, during events such as rough road driving conditions
or other conditions which result in large displacements of the
engine and/or any other powertrain component to which the mount is
connected, the decoupler 46 may be de-energized or forced to become
rigid or expand to substantially fill the space 42 so that fluid
may be forced from the pumping chamber 30 through the orifice track
24 by way of the ports 28 and 26 into the reservoir 32 and
vice-versa. Accordingly, under such conditions the mount 10
exhibits a higher dynamic stiffness to control large-scale
displacements of the engine and/or other component of the
powertrain to which the mount may be connected. Accordingly, the
mount 10 can be "tuned" to various operating conditions in a way
that satisfies essentially all the requirements for static
stiffness, vibration isolation and dynamic stiffness under a wide
range of operating conditions.
[0020] Referring briefly to FIG. 2, there is illustrated a diagram
of dynamic stiffness of a mount such as the mount 10 showing the
characteristics of the mount over a range of zero to thirty Hertz
(Hz) wherein there is no control over the decoupler member 46. This
characteristic is indicated by the curve 70. The example given is
using as a model a four-cylinder engine supported by the mount 10
at a crankshaft speed of 720 rpm resulting in a secondary vibration
of 24 Hertz transmitted from the engine to the mount. However, the
curve 72 shows the effect of energizing the electroactive polymer
decoupler member 46 to change its shape. The mount 10 may be
energized cyclically at the frequency of the vibration to be
isolated and also at a selected phase angle in relation to the
vibration.
[0021] The construction and operation of the mount 10 is believed
to be within the purview of one of ordinary skill in the art based
on the foregoing description. Conventional engineering materials
may be used to construct substantially all parts of the mount
except the decoupler member 46 which, as previously described, is
selected to be of a composition which responds to an electric field
to change its shape in one or more ways. A suitable hydraulic fluid
is provided to fill the pumping chamber 30 and the reservoir 32 in
a conventional manner. An ethylene glycol-water mixture may be
provided as the hydraulic fluid. The sizes of the orifices 26 and
28 as well as their placement relative to each other around the
orifice track 24 may also be selected in accordance with the
desired stiffness and vibration damping characteristics required
for the mount 10.
[0022] Although a preferred embodiment of the invention has been
described in detail therein, those skilled in the art will
recognize that various substitutions and modifications may be made
without departing from the scope and spirit of the appended
claims.
* * * * *