Title: Bi-state hydraulic mount
Abstract: A hydraulic mount provides active control through the use of a rotary track assembly connecting a primary pumping chamber of the mount to a secondary fluid chamber. With low amplitude vibrations the fluid path remains open, providing low dynamic stiffness. For high amplitude vibrations, the fluid flow path is closed, providing a high level of dynamic stiffness. The rotary track assembly control is continuously variable offering a wide range of active control of hydraulic mount stiffness.
Patent Number: 6,848,682 Issued on 02/01/2005 to Tewani, et al.
| Inventors:
|
Tewani; Sanjiv G. (Lebanon, OH);
Long; Mark W. (Bellbrook, OH);
Bodie; Mark O. (Dayton, OH)
|
| Assignee:
|
Delphi Technologies, Inc. (Troy, MI)
|
| Appl. No.:
|
361054 |
| Filed:
|
February 7, 2003 |
| Current U.S. Class: |
267/140.15; 267/140.14; 267/141.5 |
| Intern'l Class: |
F16F 013/00 |
| Field of Search: |
267/140.11,140.13,140.14,140.15,141.3-141.5,219,136,140.3,140.4
248/562-3,636,638
180/300,312,902
188/266.3,266.4,322.13,290
|
References Cited [Referenced By]
U.S. Patent Documents
| 4648576 | Mar., 1987 | Matsui | 267/140.
|
| 4699099 | Oct., 1987 | Arai et al. | 123/192.
|
| 4789143 | Dec., 1988 | Smith et al. | 267/140.
|
| 4802648 | Feb., 1989 | Decker et al. | 248/550.
|
| 6357730 | Mar., 2002 | Gugsch et al. | 267/140.
|
| 6547226 | Apr., 2003 | Shores et al.
| |
Primary Examiner: Siconolfi; Robert A.
Assistant Examiner: Torres; Melanie
Attorney, Agent or Firm: Smith; Michael D.
Parent Case Text
RELATED APPLICATIONS
This application claims priority to U.S. Provisional Patent Application No.
60/355,671 filed Feb. 7, 2002, titled Bi-State Hydraulic Mount by Sanjiv
G. Tewani et al.
Claims
We claim:
1. A hydraulic mount comprising:
a resilient hollow body defining a primary fluid chamber and a secondary
fluid chamber;
a rotary track assembly separating the primary and secondary fluid
chambers;
a rotary actuator operably connected to the rotary track assembly;
a controller operably connected to the rotary actuator; and
at least one sensor operably connected to the controller for sensing
vibrational amplitude,
wherein the rotary track assembly comprises:
an orifice plate including a plurality of openings;
a containment plate securely attached to the orifice plate, the containment
plate including a wall portion, the wall portion including a plurality of
tab portions defining a plurality of fluid chambers; and
a rotary track disposed between and rotatably coupled to the orifice plate
and the containment plate, the rotary track including a wall portion and a
base portion, the rotary track wall portion including a first plurality of
rotary track openings and the rotary track base portion including a second
plurality of rotary track openings; and
wherein the controller receives a sensed vibrational amplitude from the at
least one sensor and sends a signal to the rotary actuator to rotate The
rotary track assembly based on the sensed vibrational amplitude.
2. The hydraulic mount of claim 1 wherein the resilient hollow body
comprises:
a diaphragm operably connected to the rotary track assembly to define the
secondary fluid chamber; and
a resilient member operably connected to the rotary track assembly to
define the primary fluid chamber.
3. The hydraulic mount of claim 1 wherein the resilient hollow body
comprises:
a diaphragm including an outward radius disposed between a mount housing
and the rotary track assembly and an inward radius disposed between an
actuator mount and the orifice plate to define the secondary fluid
chamber; and
a resilient member coupled to the mount housing and the rotary track
assembly to define the primary fluid chamber.
4. The hydraulic mount of claim 2 wherein the resilient member includes a
rigid support.
5. The hydraulic mount of claim 1 wherein the rotary actuator is operably
connected to the rotary track.
6. The hydraulic mount of claim 5 wherein the first plurality of rotary
track openings of the rotary track wall portion are rotated to align with
the plurality of fluid chambers of the containment plate to allow for
fluid flow between the primary fluid chamber and the secondary fluid
chamber.
7. The hydraulic mount of claim 5 wherein the rotary track is rotated to
align the rotary track wall portion with the containment plate fluid
chanbers to block the flow of fluid between the primary fluid chamber and
the secondary fluid chambers.
8. The hydraulic mount of claim 1 wherein the base portion of the rotary
track is sloped.
9. The hydraulic mount of claim 5 wherein the rotary actuator rotates the
rotary track to partially block the flow of fluid between the primary
fluid chamber and the secondary fluid chamber.
10. A hydraulic mount comprising:
a resilient hollow body defining a primary fluid chamber and a secondary
fluid chamber;
an orifice plate including a plurality of openings separating the primary
fluid chamber from the secondary fluid chamber;
a containment plate securely attached to the orifice plate, the containment
plate including a wall portion, the wall portion including a plurality of
tab portions defining a plurality of fluid chambers;
a rotary track disposed between and rotatably coupled to the orifice plate
and the containment plate, the rotary tack including a wall portion and a
base portion, the rotary track wall portion including a first plurality of
rotary track openings and the rotary track base portion including a second
plurality of rotary track openings;
a rotary actuator operably connected to the rotary track and a controller;
and
at least one sensor operably connected to the controller for sensing
vibrational amplitude.
11. The hydraulic mount of claim 10 wherein the resilient hollow body
comprises:
a diaphragm operably connected to the orifice plate to define the secondary
fluid chamber, and
a resilient member operably connected to the orifice plate and a mount
housing to define the primary fluid chamber.
12. The hydraulic mount of claim 10 wherein the resilient hollow body
comprises:
a diaphragm including an outward radius disposed between a mount housing
and a rotary track assembly and an inward radius disposed between an
actuator mount and the orifice plate to define the secondary fluid
chamber; and
a resilient member coupled to the mount housing and the rotary track
assembly to define the primary fluid chamber.
Description
TECHNICAL FIELD OF THE INVENTION
This invention relates, generally, to hydraulic powertrain mounts of the
type used in motor vehicles, and more particularly to bi-state hydraulic
mounts.
BACKGROUND OF THE INVENTION
It has long been the practice in motor vehicles, such as automobiles and
trucks, to suspend engines, and other heavy components that generate
vibrations when operating, on resilient mounts that isolate and damp the
vibration from reaching the passenger compartment of the vehicle. It is
desirable in such circumstances to provide a mount that is relatively soft
for low amplitude higher frequency vibrations, such as those produced
while an engine is operating at idle speed or at a constant speed while
the vehicle is cruising along on a smooth road. Making the mount too soft,
however, results in a structure that may not be capable of damping the
motion of a heavy mass, such as the engine, when the vehicle is traveling
over a bumpy road.
The competing requirements for a mount that is soft enough to isolate low
amplitude vibrations generated by an engine at idle, and yet is robust
enough to damp and limit the movement of an engine relative to the vehicle
chassis when the vehicle is encountering a bumpy road surface, have caused
the designers of resilient mounts to employ hydraulic fluid flowing
between multiple chambers within the mount, together with judiciously
sized orifice tracks and fluid valve arrangements providing fluid
communication between the chambers, to provide mounts that exhibit
different damping performance dependent upon the magnitude and frequency
of the vibratory input to the mount, without any active external control
of fluid flow between the various chambers. Such mounts are known as
passive hydraulic mounts. However, in trying to achieve a balance between
controlling high frequency vibrations and low frequency vibrations, the
range of damping possible with passive hydraulic mounts is reduced.
One method of broadening the range of frequencies a mount is effective over
is by employing an active control mount. Active control mounts include an
electrically activated control to dynamically change the damping ability
of a mount. Often, though, these mounts are costly and complex, leading to
significant restrictions in the number of applications within which the
mount can be employed.
What is desired, therefore, is an improved bi-state hydraulic mount that
overcomes these and other disadvantages.
SUMMARY OF THE INVENTION
The present invention provides a hydraulic mount including a resilient
hollow body defining a primary fluid chamber and a secondary fluid
chamber, a rotary track assembly separating the primary and secondary
fluid chambers and a rotary actuator operably connected to the rotary
track assembly. The rotary track assembly includes an orifice plate having
a plurality of openings, a containment plate securely attached to the
orifice plate, and including a wall having a plurality of tab portions
that define a plurality of fluid chambers. The rotary track assembly
further includes a rotary track disposed between and rotatably coupled to
the orifice plate and the containment plate, the rotary track having a
wall portion and a base portion, the wall portion including a first
plurality of openings and the base portion including a second plurality of
openings.
Another embodiment of the invention provides a method for operating a
hydraulic mount having a resilient hollow body defining a primary fluid
chamber, a secondary fluid chamber, a rotary track assembly having a
rotary track providing fluid communication between the primary chamber and
the secondary chamber, and a rotary actuator, the method comprising
sensing an amplitude vibration, receiving the sensed vibration at the
controller, sending a signal to the rotary actuator and rotating the
rotary track based on the received amplitude vibration. The method further
includes rotating the rotary track to an open position in response to a
low amplitude vibration and rotating the rotary track to a closed position
in response to a high amplitude vibration.
The foregoing and other features and advantages of our invention are
apparent from the following detailed description of exemplary embodiments,
read in conjunction with the accompanying drawings. The detailed
description and drawings are merely illustrative of the invention rather
than limiting, the scope of the invention being defined by the appended
claims and equivalents thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a cross section, illustrating one embodiment of a bi-state
hydraulic mount in the closed position, in accordance with the invention;
FIG. 1B is a cross section, illustrating the bi-state hydraulic mount if
FIG. 1A in the open position, in accordance with the invention,
FIG. 2 is a detailed cross-section of one embodiment of a rotatable track
assembly utilized in the hydraulic mount of FIGS. 1A and 1B;
FIG. 3 is an exploded view of the rotatable track assembly illustrated in
FIG. 2; and
FIG. 4 is a cross section of a bi-state hydraulic mount illustrating
another embodiment of a rotary track, in accordance with the present
invention.
DETAILED DESCRIPTION
FIGS. 1A and 1B illustrate an exemplary embodiment of a bi-state hydraulic
mount 10, according to our invention. FIG. 1A illustrates mount 10 in a
closed position and FIG. 1B illustrates mount 10 in an open position.
Hydraulic mount 10 includes a resilient hollow body 12 defining a primary
fluid (pumping) chamber 14, and a secondary fluid (reservoir) chamber 16
separated from one another by a rotatable track assembly 15. Fluid
chambers are filled with an incompressible hydraulic fluid such as, for
example, glycol. Resilient hollow body 12 includes a resilient member
(elastomeric pads) 19, fabricated from natural rubber or a similar
elastomeric material, and a diaphragm 18, also fabricated from natural
rubber or a similar elastomeric material. Resilient member 19 and the
diaphragm 18 are assembled with a rotatable track assembly 15 in a fluid
tight manner to form the primary and secondary fluid chambers 14, 16.
Resilient member 19 includes a rigid metal support 13.
Mount 10 further includes a first and a second attachment device 74, 76
disposed along a mount axis 62 extending through the resilient hollow body
12 for receiving a load applied along the mount axis 62. In one
embodiment, the first attachment device 74 of the mount 10 is in the form
of a threaded stud 64 extending from a base 78 that is bonded to the
resilient hollow body 12. The second attachment device 76 of the mount 10
is also a threaded stud 66 extending from a cup shaped mount housing 72
attached to the resilient hollow body 12.
FIGS. 2 and 3, illustrate in detail, one embodiment of rotatable track
assembly 15 of mount 10 shown in FIG. 1. Rotatable track assembly 15
includes orifice plate 20, rotary track 30, containment plate 40 and
rotary actuator 50. Rotatable track assembly 15 provides fluid
communication between primary and secondary fluid chambers 14, 16.
Orifice plate 20 is disposed between mount housing 72 and resilient member
19. Orifice plate 20 includes a plurality of openings 22 for fluid
communication between primary fluid chamber 14 and containment plate 40.
The orifice plate design allows a large flow area for the hydraulic fluid
used in the mount which results in the generation of low dynamic stiffness
over a large frequency of operaton for one state of operation of the mount
10.
Containment plate 40 is securely attached to orifice plate 20. In one
embodiment, containment plate 40 is securely attached to orifice plate 20
by screws. Containment plate 40 includes wall 42. Wall 42 includes a
plurality of radially extending tabs 44. The radially extending tabs 44
define a plurality of fluid chambers 46. Fluid chambers 46 are three
sided, the sides defined by wall 42 and tabs 44 of the containment plate
40. Fluid chamber 46 includes an opening 48 that allows fluid
communication between the containment plate 40 and the secondary fluid
chamber 16 via the rotary track 30 when the rotary track 30 is in the open
position, FIG. 1B.
Rotary track 30 is rotatably disposed between orifice plate 20 and
containment plate 40. Rotary track 30 includes a sidewall portion 34 and a
base portion 36. Sidewall portion 34 defines a plurality of openings 32.
Base portion 36 defines a plurality of openings 38. Openings 32 and 38
allow for flow between the secondary fluid chamber 16 and fluid chambers
46 of containment plate 40 when the rotary track is in the open position,
FIG. 1B. The number and size of openings 32 of rotary track 30 correspond
to the number size of the openings 48 of fluid chambers 46 of containment
plate 40. Those skilled in the art will recognize that the number and size
of the openings 22, 32 and 48 within their respective structures may be
varied as required to suit the specific application.
Rotary track 30 also includes axial opening 82 through which rotary track
30 is operably connected to rotary actuator 50. In the embodiment of the
mount 10 shown in FIG. 2, rotary actuator 50 is mounted in an actuator
mount 52 attached to orifice plate 20 via fasteners 54. Rotary actuator 50
is operably connected to a controller and is sealed from operation of the
rotatable track. The controller determines vibration frequencies through
sensors 98 operably connected to the controller and rotates the rotary
actuator 50 to rotate the rotary track 30 to the open or closed position
in response to the sense vibration frequencies. Those skilled in the art
will recognize that, in other embodiments, the rotatable track is
continuously variable in position allowing for the track to remain
partially open or closed depending on the vibrational input received by
the controller from sensor located on the vehicle.
Diaphagm 18 includes an outward radius 24 and an inward radius 26. Outward
radius 24 is disposed between the mount housing 72 and the orifice plate
20. Inward radius 26 is disposed between actuator mount 52 and orifice
plate 20. Those skilled in the art will recognize that there are various
other configurations for restraining diaphragm 18 in order to form the
secondary fluid chamber 16.
In operation, the dynamic stiffness of the mount 10 can be changed from a
low rate to a high rate through electronic means by using the rotary
actuator 50. In the open position of the rotary track 30, illustrated in
FIG. 1B, there is fluid communication between the primary and secondary
chambers, 14, and 16 via the alignment of rotary track openings 32 with
containment plate openings 48 as illustrated by fluid flow pathway A. With
this alignment of the openings, there is no resistance to the fluid flow
between the fluid chambers. As a result, the force generated by the mount
to any input displacement is due to the shear and compression of the
elastomeric resilient member 19. Therefore, in this soft mode of operation
(i.e. the open position), the elastomeric resilient member 19 is
relatively easily deflected, with fluid being pumped through the fluid
path between the primary and secondary chambers. This mode of operation
provides a low dynamic stiffness that is desirable for attenuating low
amplitude vibrations.
When a higher rate of dynamic stiffness is desired, the fluid path between
the primary and secondary fluid chambers may be closed. This fluid path is
closed by rotating the rotary track 30 until the rotary track wall 34
aligns with openings 48, thereby blocking the flow of fluid between the
primary and secondary fluid chambers. Blocking the fluid flow in this
manner locks the incompressible fluid between the orifice plate and the
resilient member 19. As a result, for any input to the mount 10, the
volumetric change in the primary (pumping) chamber 14 is achieved by the
bulging of the resilient member 19. This mode of operation provides a firm
level of control for large amplitude inputs such as those from torque
transient events.
FIG. 4 shows a second embodiment of a mount 100, according to our
invention, having a rotary track 90 of a different shape than the rotary
track 30 shown in FIGS. 1A to 3. The second orifice track 90 of FIG. 4
includes a sloped base portion having angled openings 92 into the primary
fluid chamber 94. The fluid flow pathway B of mount 100 is similar to the
fluid flow pathway A of mount 10.
Those skilled in the art will recognize that the rotary actuator 50 can be
energized at any time or frequency, to change the performance of the mount
10. Because actuation of the rotary track 30 is done actively, rather than
passively, a mount 10 according to the invention offers greater
flexibility of operation.
It will also be recognized, that although the embodiments disclosed herein
use a simple two-state operation of the actuator 50 to completely open, or
alternatively to completely close the fluid path, in other embodiments of
our invention it may be desirable to utilize the actuator 50 for
modulating fluid flow to thereby provide continuously variable control of
the mount characteristics. It is contemplated that in other embodiments of
the invention, it may be desirable to control the actuator 50 with a
technique such as pulse width modulation.
While the embodiments of the invention disclosed herein are presently
considered to be preferred, various changes and modifications can be made
without departing from the spirit and scope of the invention.
For example, although the exemplary embodiments expressly disclosed herein
utilize an electrically activated actuator 50, other types of actuators
using power sources such as fluid pressure, vacuum, or mechanical force
may also be used in practicing the invention.
The various elements and aspects of the invention may also be used
independently from one another, or in different combinations or
orientations than are described above and in the drawing with regard to
the exemplary embodiment. It is expressly emphasized that the first and
second attachment devices 74, 76 may take many other forms, and can be
oriented at an angle to one another and/or the mount axis 62 to facilitate
use of the invention in a wide range of applications. It is also expressly
emphasized that the invention may be practiced in mounts providing
resilient support of a wide variety of masses, in addition to the
automotive engine mounts described herein.
The scope of the invention is indicated in the appended claims. It is
intended that all changes or modifications within the meaning and range of
equivalents are embraced by the claims.
*
