U.S. patent application number 09/780857 was filed with the patent office on 2002-08-15 for vacuum actuated active decoupler mount.
Invention is credited to Baudendistel, Thomas A., Dingle, James E., Long, Mark W., Tewani, Sanjiv G..
Application Number | 20020109066 09/780857 |
Document ID | / |
Family ID | 25120917 |
Filed Date | 2002-08-15 |
United States Patent
Application |
20020109066 |
Kind Code |
A1 |
Baudendistel, Thomas A. ; et
al. |
August 15, 2002 |
VACUUM ACTUATED ACTIVE DECOUPLER MOUNT
Abstract
A hydraulic engine mount includes opposed mounting members
secured to an elastomeric body and a base, respectively, and an
orifice plate assembly interposed the body and the base to define a
pumping chamber and a reservoir or opposed pumping chambers for
fluid to flow therebetween through an orifice track formed by the
orifice plate assembly. One or two elastomeric decoupler discs may
be secured in recesses between two orifice plates of the orifice
plate assembly and form spaces which are operable to be in
communication with a vacuum source to impose vacuum pressure on the
decouplers at selected frequencies as controlled by solenoid
operated valves and a controller. The mount may be operated at a
substantially reduced dynamic stiffness lower than the static
stiffness of the mount to provide improved low amplitude vibration
isolation, in particular.
Inventors: |
Baudendistel, Thomas A.;
(Farmersville, OH) ; Tewani, Sanjiv G.; (Lebanon,
OH) ; Long, Mark W.; (Bellbrook, OH) ; Dingle,
James E.; (Cincinnati, OH) |
Correspondence
Address: |
Scott A. McBain
Delphi Technologies
P.O. Box 5052
Mail Code: 480-414-420
Troy
MI
48007-5052
US
|
Family ID: |
25120917 |
Appl. No.: |
09/780857 |
Filed: |
February 9, 2001 |
Current U.S.
Class: |
248/562 ;
248/550 |
Current CPC
Class: |
F16F 2230/183 20130101;
F16F 13/268 20130101 |
Class at
Publication: |
248/562 ;
248/550 |
International
Class: |
F16M 013/00 |
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 said mounting members and a base connected to the other of
said mounting members; a partition; a first chamber formed between
said body and said partition and a second chamber formed between
said partition and a member interposed said partition and said
base; at least one decoupler supported by said partition and in
fluid communication with one of said chambers; and a space formed
between said one decoupler and said partition and operable to be in
communication with a source of vacuum in such a way as to cause
said mount to damp vibrations in a predetermined frequency
range.
2. The mount set forth in claim 1 where: said partition is
interposed said body and said base.
3. The mount set forth in claim 1 wherein: said partition comprises
an orifice track for transferring fluid between said chambers.
4. The mount set forth in claim 1 wherein: said member interposed
said partition and said base comprises a flexible diaphragm
delimiting one of said chambers.
5. The mount set forth in claim 1 wherein: said partition comprises
an orifice plate assembly including a first orifice plate member
having a plurality of openings therein for providing fluid
communication between one of said chambers and said one decoupler,
a second orifice plate member, and said space is formed between
said second orifice plate member and said decoupler.
6. The mount set forth in claim 5 wherein: said second orifice
plate member includes a recess formed therein delimited by a
peripheral wall, and said one decoupler is secured in said recess
in fluid tight sealing engagement with said wall.
7. The mount set forth in claim 5 wherein: said orifice plate
assembly includes spaces formed between said second orifice plate
and said one decoupler and between said second orifice plate member
and another decoupler, said decouplers being in fluid flow
communication with fluid in said chambers, respectively.
8. The mount set forth in claim 7 including: separate conduits
connected to said partition for communicating pressure fluid to and
from said spaces, respectively, and control valves connected to
said conduits between said decouplers and said vacuum source,
respectively, and operable to place said decouplers in
communication with vacuum pressure and a pressure greater than said
vacuum pressure to effectively control the dynamic stiffness of
said mount at predetermined vibration frequencies.
9. The mount set forth in claim 8 wherein: said decouplers each
comprise an elastomeric disc having an outer rim forcibly engaged
with said orifice plate assembly to provide a fluid tight seal to
prevent leakage of fluid into said spaces between said decouplers
and said orifice plates from said chambers, respectively.
10. The mount set forth in claim 8 including: a controller operably
connected to said valves and operable to effect operation of said
valves at selected frequencies between a condition for
communicating said spaces with said vacuum source and a condition
for venting said spaces, respectively.
11. The mount set forth in claim 10 wherein: said controller
includes means operable to effect movement of said decouplers at a
predetermined frequency related to a frequency of vibration input
to said mount and at a predetermined phase angle related to said
vibration.
12. The mount set forth in claim 5 including: a conduit connected
to said orifice plate assembly for communicating pressure fluid to
and from said space and a control valve connected to said conduit
between said decoupler and said vacuum source and operable to place
said decoupler in communication with vacuum pressure and a pressure
greater than said vacuum pressure to effectively control the
dynamic stiffness of said mount at predetermined vibration
frequencies.
13. The mount set forth in claim 12 wherein: said decoupler
comprises an elastomeric disc having an outer rim forcibly engaged
with said orifice plate assembly to provide a fluid tight seal to
prevent leakage of fluid into said space between said decoupler and
said second orifice plate from said chamber.
14. The mount set forth in claim 13 including: a controller
operably connected to said valve and operable to effect operation
of said valve at selected frequencies between a condition for
communicating said space with said vacuum source and a condition
for venting said space, respectively.
15. The mount set forth in claim 14 wherein: said controller
includes sensor means for effecting operation of said controller to
control movement of said decoupler at a predetermined frequency
related to a frequency of vibration input to said mount.
16. A hydraulic mount for an operating component of a vehicle
comprising: first and second mounting members; a body connected to
one of said mounting members and a base connected to the other of
said mounting members; an orifice plate assembly; a pumping chamber
formed between said body and said orifice plate assembly; a
decoupler supported by said orifice plate assembly and in fluid
communication with said pumping chamber; a space formed between
said decoupler and said orifice plate assembly; a conduit connected
to said orifice plate assembly for communicating pressure fluid
between said conduit and said space; and a control valve connected
to said conduit and a vacuum source and operable to alternately
place said decoupler in communication with vacuum pressure and a
pressure greater than said vacuum pressure to effectively reduce
the dynamic stiffness of said mount at a predetermined vibration
frequency.
17. The mount set forth in claim 16 including: an orifice track
formed by said orifice plate assembly for transferring fluid
between said pumping chamber and a reservoir in said mount.
18. A hydraulic mount for an operating component of a vehicle
comprising: first and second mounting members; a body connected to
one of said mounting members and a base connected to the other of
said mounting members; an orifice plate assembly; a pumping chamber
formed between said body and said orifice plate assembly and a
reservoir formed between said orifice plate assembly and a member
interposed said orifice plate assembly and said base; an elastomer
disc decoupler supported by said orifice plate assembly and in
fluid communication with said pumping chamber; a space formed
between said decoupler and said orifice plate assembly; a conduit
connected to said orifice plate assembly for communicating pressure
fluid between a vacuum source and said space; and a control valve
connected to said conduit between said decoupler and said vacuum
source and operable to alternately place said decoupler in
communication with vacuum pressure and a pressure greater than said
vacuum pressure to effectively reduce the dynamic stiffness of said
mount at a predetermined vibration frequency.
19. The mount set forth in claim 18 including: a controller
operably connected to said valve and operable to cause said valve
to communicate said space with said vacuum source to effect
movement of said decoupler at a predetermined frequency related to
a frequency of vibration input to said mount.
20. The mount set forth in claim 19 including: at least one of a
vibration sensor and engine speed sensor operably connected to said
controller.
21. A hydraulic mount for an operating component of a vehicle
comprising: first and second mounting members; opposed elastomeric
body members connected to one of said mounting members and a base
connected to the other of said mounting members; an orifice plate
assembly; a first fluid filled pumping chamber formed between one
of said body members and said orifice plate assembly and a second
fluid filled pumping chamber formed between said orifice plate
assembly and the other of said body members; opposed elastomer disc
decouplers supported by said orifice plate assembly and in fluid
communication with said pumping chambers, respectively; opposed
spaces formed between said decouplers and said orifice plate
assembly, respectively; conduits connected to said orifice plate
assembly for communicating pressure fluid between a vacuum source
and said spaces, respectively; and control valves connected to said
conduits between said decouplers and said vacuum source and
operable to alternately place said decouplers in communication with
vacuum pressure and a pressure greater than said vacuum pressure to
modify the dynamic stiffness of said mount.
22. The mount set forth in claim 21 including: a controller
operably connected to said valves and operable to cause said valves
to communicate said spaces with said vacuum source to effect
movement of said decouplers at predetermined frequencies related to
frequencies of vibration input to said mount.
23. The mount set forth in claim 22 including: at least one of a
vibration sensor and engine speed sensor operably connected to said
controller.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to a hydraulic mount,
particularly adapted for motor vehicle applications, including a
vacuum actuated decoupler operable to modify the dynamic stiffness
of the mount.
BACKGROUND
[0002] Conventional automotive vehicle powertrain mounts exist in
many variations and generally operate to provide engine vibration
isolation while also controlling engine motion with respect to the
vehicle frame or body structure. In many applications of engine and
powertrain mounts, it is desirable to vary the dynamic stiffness of
the mount to provide selective isolation of vibrations at certain
frequencies related to engine speed, for example.
[0003] By way of example, for a four cylinder engine, the mount is
desirably made to provide lower dynamic stiffness at the frequency
of vibration related to the second order of engine speed
(revolutions per minute). Accordingly, if the dynamic stiffness of
the mount assembly can be varied and can be made lower than the
static stiffness of the mount, improved vibration isolation can be
obtained to reduce noise and vibration transmitted from the engine
into the vehicle structure. It is to these ends that the present
invention has been developed.
SUMMARY OF THE INVENTION
[0004] The present invention provides a mount, particularly adapted
for automotive vehicle powertrain mount applications, which
utilizes one or more decouplers which can be controlled to provide
a lower dynamic stiffness of the mount assembly at predetermined
frequencies to thereby provide improved vibration isolation between
the structure supported by the mount and the structure supporting
the mount.
[0005] In accordance with an important aspect of the present
invention, a hydraulic engine mount is provided which is
characterized by an elastomer body defining a fluid pumping
chamber, a partition interposed the elastomer body and a fluid
reservoir and an orifice track communicating hydraulic fluid
between the pumping chamber and the reservoir. The reservoir is
preferably delimited by a flexible diaphragm and the mount includes
an elastomer type decoupler to aid in isolating relatively high
frequency, low displacement vibrations. However, the decoupler may
be modified in its performance characteristics by applying a vacuum
to one side of the decoupler to modify the performance of the
mount, particularly by substantially reducing the dynamic stiffness
of the mount at predetermined vibration frequencies.
[0006] In accordance with another aspect of the present invention,
a hydraulic type mount is provided which includes one or more
active decouplers which may be controlled by solenoid operated
valves, respectively, and a source of vacuum to modify the dynamic
stiffness of the mount to isolate vibrations at particular
frequencies. The decoupler or decouplers may be actuated at the
same frequency as the vibrations being input to the mount and the
phase angle of actuation of the decoupler may be selectively
varied. The dynamic stiffness of the mount may be modified to be
lower than the static stiffness to improve the vibration isolation
characteristics of the mount, particularly for low amplitude
relatively high frequency vibrations.
[0007] In accordance with still another aspect of the present
invention, a hydraulic mount is provided which includes opposed
pumping chambers and opposed vacuum actuated active decouplers
which may be selectively actuated to provide for a wider range of
stiffness of the mount at selected frequencies. For example, if the
mount was supporting an engine that generates large second order
shaking forces, the decouplers could vibrate in phase with these
forces which would make the mount softer and operable to isolate
such forces.
[0008] Those skilled in the art will further appreciate the above
mentioned advantages and 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 DRAWINGS
[0009] FIG. 1 is a longitudinal central section view of a vacuum
actuated active decoupler mount in accordance with the present
invention;
[0010] FIG. 2 is a diagram illustrating a force versus frequency
characteristic for the mount shown in FIG. 1; and
[0011] FIG. 3 is a longitudinal central section view of an
alternate embodiment of a vacuum actuated active decoupler 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 drawings are not necessarily to scale
and certain features may be shown in somewhat generalized or
schematic form in the interest of clarity and conciseness.
[0013] Referring to FIG. 1, there is illustrated a hydraulic mount
in accordance with the invention and generally designated by the
numeral 10. The mount 10 includes a generally cylindrical cup
shaped formed metal base number 12 suitably secured to a mounting
member or bracket assembly 14 in a conventional manner. The base
number 12 includes a peripheral sidewall 16 and a circumferential
radially outwardly projecting flange 18. The mount 10 is further
characterized by a generally cylindrical molded elastomer body 20
which is reinforced by an encapsulated, flexible, thin walled metal
core part 22. The body 20 is molded to a central metal hub member
24 which supports a threaded mounting member 26 for connecting the
mount 10 to an engine assembly or the like. The elastomer body 20
includes a central, generally cylindrical depending portion 28
which, in the position shown, is engageable with an orifice track
assembly 32. Orifice track assembly 32 includes an upper, generally
planar, cylindrical orifice plate 34 and a lower, generally planar,
cylindrical orifice plate 36. Orifice plates 34 and 36 are shown in
assembly to define an annular passage or orifice track 38 which
opens through a port 40 to a fluid pumping chamber 42 formed
between the body 20 and the orifice plate assembly 32. A
circumferentially spaced port 29 communicates hydraulic fluid
between orifice track 38 and a second fluid chamber or reservoir
60.
[0014] Lower orifice plate 36 also defines a generally cylindrical
central recess 44 in which is disposed an elastomeric cylindrical
disc shaped decoupler member 46 which is preferably dimensioned to
include opposed, shallow, annular recess or channel portions 48 and
50. Recess 44 is defined by a peripheral outer wall 52 and a
reduced diameter generally planar bottom wall surface 54 which is
relieved to provide a space between wall surface 54 and a major
part of a disc shaped body portion 49 of decoupler 46, as shown.
The decoupler 46 is also characterized by a circumferential rim
part 47 which is trapped in fluid tight sealing engagement between
the upper orifice plate 34 and the lower orifice plate 36. However,
a major part of the body 49 of the decoupler 48, radially inward of
the rim 47, is allowed limited space within the recess 44 between
the wall surface 54 and the upper orifice plate 34.
[0015] Upper orifice plate 34 is also provided with a relieved
cylindrical wall surface 37 to provide space between decoupler 46
and orifice plate 34 except at the rim 47. The space defined
between the wall surface 54 and the decoupler 46, for example, may
be vented through a port 57 formed in an otherwise fluid tight plug
58 shown disposed in a suitable opening formed in the lower orifice
plate 36. Plug 58 also includes a flange or head 59 engaged with a
central hub portion of a generally cup shaped flexible elastomer
diaphragm 62. Diaphragm 62 delimits the reservoir 60, as shown in
FIG. 1.
[0016] The hydraulic mount 10 is shown in a position wherein the
cylindrical body portion 28 of the elastomer body 20 rests on the
orifice plate 34. However, under mount operating conditions,
hydraulic fluid is also present in a pumping chamber portion 43
which is in direct communication with the chamber 42. Moreover, as
mentioned above, the decoupler member 46 is dimensioned such that
there is some free space for movement between the decoupler and the
orifice plates 34 and 36. Suitable passages 35 are formed in the
orifice plate 34 to allow communication of fluid between the
pumping chamber 42, 43 and the space between the decoupler 46 and
the orifice plate 34.
[0017] The hydraulic mount 10 also includes the aforementioned
fluid reservoir 60 defined by and between the flexible diaphragm 62
and the orifice plate 36. The diaphragm 62 includes a
circumferential rim portion 64 which is shown nested in a suitable
annular groove 65 formed in the lower orifice plate 36.
[0018] As further shown in FIG. 1, the mount 10 may be assembled by
securing the rim 64 of the diaphragm 62 between the flange 18 of
the base member 12 and the periphery of the orifice plate 36. The
orifice plates 34 and 36 are also held in fluid tight assembly with
each other at their peripheral edges by a circumferential rim
portion 21 of the body 20 which is suitably displaced to form a
radially inwardly directed peripheral flange 23 contiguous with the
base member flange 18. A suitable rivet type plug 66 projects
through the wall of the body 20 and closes a fill port for filling
the pumping chamber 42, 43 and the reservoir chamber 60 with a
suitable hydraulic fluid, such as a mixture of water and ethylene
glycol.
[0019] Referring still further to FIG. 1, the mount 10 includes a
suitable connector 70 for a conduit 72 which extends through an
opening 12a in the base plate and extends to a control valve 74.
Control valve 74 is operable to be in communication with a source
of vacuum 76 which, for example, may be a conventional vacuum
reservoir onboard an automotive vehicle used for other vacuum
operated components of the vehicle. The control valve 74 may, as
shown, comprise a two position solenoid actuated valve and is
preferably connected to a suitable controller 78 which may include
a vibration sensor 78a and/or an engine speed sensor 78b operably
connected thereto. Controller 78 is also operably connected to a
source of electrical power, not shown, and the controller is
operable to control the valve 74 to impose a vacuum on the space
within recess 44 disposed between the decoupler 46 and the wall
surface 54 to deflect the decoupler as a consequence of changes in
fluid pressure acting on the decoupler. In the position a of valve
74 the space between decoupler 46 and wall surface 54 may be
"vented" to atmospheric pressure or merely blocked wherein the
vented condition would not see any change in pressure acting on the
decoupler.
[0020] For example, the valve 74 may be energized to move
cyclically between positions a and b to cause the decoupler 46 to
be actuated at the same frequency as a particular input vibration
imposed on the mount 10 and at a predetermined phase angle to the
input vibration displacement such that a substantial reduction in
the resistance to motion of the mount is obtained. In this way, a
large reduction in the dynamic stiffness of the mount 10 may be
obtained. Accordingly, the mount 10 may be operated in such a way
as to be "softer" at certain vibration frequencies to which the
mount is exposed. By actuating or deflecting the decoupler 46 by
the imposition of vacuum pressure thereon, the dynamic stiffness of
the mount 10 can be reduced substantially at selected vibration
frequencies and thereby provide excellent isolation between an
engine and a body or frame structure of an automotive vehicle, for
example. The controller 78 and valve 74 may be operated to provide
selective isolation characteristics for the mount 10 at certain
frequencies related to engine crankshaft speed (rpm). For example,
the mount 10 can be made to provide lower dynamic stiffness at a
frequency related to the second order of the rotational speed (rpm)
of the engine crankshaft of an inline four cylinder engine.
[0021] Referring to FIG. 2, there is illustrated a diagram of force
in Newtons (N) versus time in seconds (sec). The curves of FIG. 2
illustrate operating conditions wherein the mount 10 is vibrated at
an input displacement thereto at a frequency of thirty Hertz (Hz)
and the force required to move the mount at a particular
displacement was recorded. The curve 80 indicates the forces
required to move the mount 10 at a vibration frequency of thirty
Hertz and a vibration displacement of 0.1 millimeters (mm)
peak-to-peak when the space between the decoupler 46 and the wall
surface 54 is continuously vented to atmosphere, for example. The
curve 82 indicates the forces required to move the mount 10 at the
same vibration displacement and frequency when the aforementioned
space is connected to the source of vacuum 76 and vented to
atmosphere, alternately, at a frequency of thirty Hertz and an
appropriate phase angle with respect to the oscillatory vibration
input to the mount. The aforementioned phase angle will be
dependent on response time of valve 74, and materials and geometry
of the components of the mount 10. It may be observed from FIG. 2
that the forces required to effect displacement of the mount 10 for
the vibration displacement and frequency mentioned above are less
for the vacuum actuated decoupler 46 as compared with the situation
where the decoupler is continuously vented directly to atmospheric
pressure, for example.
[0022] Those skilled in the art will appreciate from the foregoing
description and drawing figures that the mount 10, being of a
decoupled typed, may be operated to respond to input vibrations in
a manner which is softened versus a nondecoupled mount or a
non-externally actuated decoupler mount of the same general
configuration. Of course, the orifice track 38 is subject to design
variations with regard to predetermined track cross sectional areas
and length, depending on the so-called design tuning frequency of
the mount.
[0023] Still further, the configuration of the mount 10 exhibits
damping forces much lower than a nondecoupled mount since some of
the fluid within the mount deflects the decoupler 46. The pumping
stiffness of the chamber 42, 43 may be modified by the decoupler 46
and the vacuum chamber defined between the decoupler and the wall
surface 54, resulting in a softer feel in a vehicle wherein the
vehicle engine is supported by mounts such as the mount 10. The
orifice plates 34 and 36 are dimensioned such that sufficient
motion of the decoupler 46 is allowed without the decoupler
impinging strongly on the orifice plates. When the input amplitude
is sufficient to move the decoupler 46 forcibly against the wall
surface 54, the pumping stiffness of the mount 10 increases further
and all the additional pumping pushes fluid through the orifice
track 38.
[0024] Referring now to FIG. 3, there is illustrated, in somewhat
schematic form, an alternate embodiment of a vacuum actuated
hydraulic mount in accordance with the invention and generally
designated by the numeral 90. The hydraulic mount 90 is
characterized by opposed, somewhat frustoconical shaped elastomeric
body members 92 and 94 between which is disposed a generally
cylindrical partition 96. The body members 92 and 94 include
generally circular peripheral rim portions 93 and 95, respectively,
which are engaged with opposed faces 97 and 99 of partition 96 and
are forcibly secured thereto fluid tight sealed relationship by a
generally cylindrical circumferential collar part 100 of a
generally cylindrical can-shaped support base member 102. The
cylindrical collar 100 is formed with a reentrant circumferential
edge 103 spaced from and opposed to a circumferential flange
portion 105 for clamping the rim portions 93 and 95 of the body
members to the partition 96. Body members 92 and 94 are,
respectively, suitably secured to mounting element hub members 106
and 108 which are, in turn, secured to a generally rectangular ring
shaped mounting bracket 110. Mounting bracket 110 is preferably
formed as a generally rectangular perimeter or ring shaped member
to allow clearance for the body members 92 and 94 between opposed
side parts 112 and 114 which are interconnected by further opposed
side parts 116, one shown, to provide a generally rectangular
perimeter configuration of the mounting bracket. Side parts 112 and
114 are suitably fixed to hub members 106 and 108, respectively. A
threaded shank part 118 is suitably secured to the side part 112 of
mounting bracket 110. In like manner, a threaded shank type
mounting element 120 is coaxial with and extends in a direction
opposite to the direction of the mounting element 118 and is
secured to a bottom wall 102a of base member 102.
[0025] 47. Opposed fluid filled pumping chambers 124 and 126 are
formed between the body member 92 and the partition 96 and between
the body member 94 and the partition 96, respectively, as
illustrated. Partition 96 is characterized by opposed, separable,
generally circular disc orifice plate members 128 and 130 which
include, respectively, generally circular centrally positioned
recesses 132 and 134 formed therein. Recesses 132 and 134 are
isolated from each other by a third plate member of partition 96
and generally designated by numeral 136. Plate member 136 is formed
with two opposed annular rims 138 and 140 which are engageable,
respectively, with the peripheral edges of circular disc elastomer
decoupler members 142 and 144, respectively. The decoupler members
142 and 144 are retained in the recesses 132 and 134 by the plate
member 136 when the plate members 128 and 130 are assembled to form
the partition 96 and retained forcibly engaged with each other by
the clamping arrangement provided by the collar 100. Decoupler
members 142 and 144 are in communication with fluid in the chambers
124 and 126 through respective ports 146 and 148 formed in the
plate members 128 and 130 and opening into the recesses 132 and
134, respectively.
[0026] The decoupler members 142 and 144 also, respectively, form
opposed chambers 150 and 152 between the respective decoupler
members and the partition plate 136. Chamber 150 is in fluid flow
communication with a vacuum conduit 153 by way of a passage 154
formed in plate 128. In like manner, chamber 152 is in fluid flow
communication with a conduit 155 by way of a passage 156 formed in
partition plate 130. The partition plates 128 and 130 are also
formed with an orifice track formed by partial annular channel
portions 160 and 162 which overlap with each other sufficiently to
provide communication of hydraulic fluid between chambers 124 and
126 through the channel portions 160 and 162 and via a port 164
which opens from channel portion 160 to chamber 124 and a port 166
which opens from channel portion 162 to chamber 126.
[0027] The mount 90 is adapted to be controlled by a controller 78d
similar to the controller 78 but adapted for controlling two
solenoid operated valves 74, each operable to be in fluid flow
communication with vacuum source 76 and with the conduits 153 and
155, as shown in FIG. 3. Controller 78d is also operable to receive
signals from a vibration sensor 78a and/or a engine speed (RPM)
sensor 78b.
[0028] Accordingly, the mount 90 may be operated in a manner
similar to the mount 10 but has the added advantage of being
capable of changing its stiffness over a wider range of frequencies
and vibration amplitudes by employing opposed vacuum actuated
active decouplers 142 and 144 to increase the range of stiffness of
the mount. The mount 90 may be operated in generally the same
manner as the mount 10.
[0029] The construction and operation of the mounts 10 and 90 is
believed to be understandable to those of ordinary skill in the art
based on the foregoing description and the drawing figures.
Conventional engineering materials may be used to construct the
mounts 10 and 90.
[0030] Although a preferred embodiment has been described in detail
therein, those skilled in the art will recognize that various
substitutions and modifications may be made to the invention
without departing from the scope and spirit of the appended
claims.
* * * * *