U.S. patent application number 10/294019 was filed with the patent office on 2006-05-11 for toroidal rotary damper apparatus.
Invention is credited to Norick B. Moradian.
Application Number | 20060096818 10/294019 |
Document ID | / |
Family ID | 36315169 |
Filed Date | 2006-05-11 |
United States Patent
Application |
20060096818 |
Kind Code |
A1 |
Moradian; Norick B. |
May 11, 2006 |
TOROIDAL ROTARY DAMPER APPARATUS
Abstract
A toroidal rotary damper apparatus includes a housing having a
toroidal inner housing surface and a piston moveable in the housing
having a curved outer peripheral piston surface in engagement with
the inner housing surface. A fluid barrier is attached to the
housing and located in the housing interior. A flow control
passageway defined by either the piston or the fluid barrier
controls passage of damper fluid when there is relative rotational
movement between the piston and the housing to dampen the forces
causing relative rotational movement.
Inventors: |
Moradian; Norick B.;
(Berkeley, CA) |
Correspondence
Address: |
THOMAS R. LAMPE;BIELEN, LAMPE & THOEMING
1390 WILLOW PASS ROAD, SUITE 1020
CONCORD
CA
94520
US
|
Family ID: |
36315169 |
Appl. No.: |
10/294019 |
Filed: |
November 12, 2002 |
Current U.S.
Class: |
188/306 |
Current CPC
Class: |
F16F 9/145 20130101 |
Class at
Publication: |
188/306 |
International
Class: |
F16F 9/14 20060101
F16F009/14 |
Claims
1. Toroidal rotary damper apparatus comprising, in combination: a
housing defining a housing interior for containing damper fluid,
said housing interior at least partially formed by a toroidal inner
housing surface disposed at least partially about and uniformly
spaced from a central axis; a piston in said housing interior
having a substantially circular outer peripheral piston surface
extending at least substantially completely about said at least one
piston in substantially fluid-tight engagement with said toroidal
inner housing surface, said piston being spaced from said axis and
said piston being movable relative to said housing within said
housing interior along at least a portion of a circular path
orthogonal to said axis and surrounding said axis with said
substantially circular outer peripheral surface thereof always
disposed co-planar with said axis and always uniformly spaced from
said axis; a fluid barrier attached to said housing and positioned
in said housing interior; a flow control passageway defined by
either said piston or said fluid barrier for permitting controlled
passage of damper fluid therethrough responsive to relative
rotational movement between said piston and said housing to dampen
forces applied to the toroidal damper apparatus causing said
relative rotational movement, said housing interior along the
length thereof having a uniform, substantially circular
cross-section in the plane occupied by said substantially circular
outer peripheral piston surface and said axis, and said housing
substantially surrounding and engaging said substantially circular
outer peripheral piston surface; and a shaft co-axial with said
axis extending through said housing interior along said axis
orthogonal to said circular path, said shaft including a radially
outwardly protruding member disposed within the housing engaging
said piston, said shaft and said piston being jointly rotatably
movable about said axis relative to said housing.
2. (canceled)
3. (canceled)
4. (canceled)
5. The toroidal rotary damper apparatus according to claim 1
wherein said piston includes an outer seal at least partially
defining said substantially circular outer peripheral piston
surface.
6. (canceled)
7. The toroidal rotary damper apparatus according to claim 31
additionally comprising compression seals positioned in said
housing surrounding said shaft for maintaining pressure of damper
fluid within said housing interior.
8. The toroidal rotary damper apparatus according to claim 7
additionally comprising radial seals positioned in said housing
surrounding said shaft housing interior.
9. The toroidal rotary damper apparatus according to claim 1
wherein said flow control passageway is defined by said piston,
said toroidal rotary damper apparatus additionally comprising a
valve mounted on said piston for selectively regulating flow of
damper fluid through said flow control passageway responsive to
relative rotational movement between said piston and said
housing.
10. The toroidal rotary damper apparatus according to claim 1
wherein said flow control passageway is defined by said fluid
barrier, said toroidal rotary damper apparatus additionally
comprising a valve mounted on said fluid barrier for selectively
opening or closing said flow control passageway responsive to
relative rotational movement between said piston and said
housing.
11. The toroidal rotary damper apparatus according to claim 9
wherein said flow control passageway is one of a plurality of flow
control passageways defined by said piston and wherein said valve
is one of a plurality of valves mounted on said piston for
selectively opening or closing said plurality of flow control
passageways responsive to relative rotational movement between said
piston and said housing.
12. The toroidal rotary damper apparatus according to claim 10
wherein said flow control passageway is one of a plurality of flow
control passageways defined by said fluid barrier and wherein said
valve is one of a plurality of valves mounted on said fluid barrier
for selectively regulating flow of damper fluid through said
plurality of flow control passageways responsive to relative
rotational movement between said piston and said housing.
13. The toroidal rotary damper apparatus according to claim 1
wherein said piston is one of a plurality of pistons fixedly
attached to said shaft, said pistons defining a space therebetween
and radiating outwardly from said shaft.
14. The toroidal rotary damper apparatus according to claim 13
wherein at least one of said pistons defines said fluid flow
passageway, said fluid flow passageway being in fluid flow
communication with said space.
15. The toroidal rotary damper apparatus according to claim 13
wherein said fluid barrier is one of a plurality of fluid barriers
positioned in said housing interior, said fluid barriers being
spaced from one another to divide said housing interior into a
plurality of chambers, each of said chambers accommodating a piston
therein.
16. The toroidal rotary damper apparatus according to claim 9
additionally comprising a valve control for controlling operation
of said valve.
17. The toroidal rotary damper apparatus according to claim 9
wherein said valve is a spring valve.
18. The toroidal rotary damper apparatus according to claim 1
additionally comprising damper preload structure for pressurizing
damper fluid in said housing interior.
19. The toroidal rotary damper apparatus according to claim 18
wherein said damper preload structure comprises a gas filled
structure located in said housing interior and in direct contact
with said damper fluid.
20. The toroidal rotary damper apparatus according to claim 1
wherein said housing includes at least one external connector
portion for connecting said housing to a structural element.
21. The toroidal rotary damper apparatus according to claim 20
wherein said shaft is fixed against rotational movement whereby
said housing will rotate about said shaft responsive to a force
exerted on said housing by said structural element.
22. The toroidal rotary damper apparatus according to claim 1
wherein said housing includes two external connector portions
spaced from one another for connecting said housing to two
relatively movable structural elements.
23. The toroidal rotary damper apparatus according to claim 22
wherein said shaft is fixed against rotational movement whereby
said housing will rotate about said shaft responsive to opposed
forces exerted on said housing by said structural elements.
24. The toroidal rotary damper apparatus according to claim 1
additionally comprising at least one link member attached to said
shaft and rotatable therewith.
25. The toroidal rotary damper apparatus according to claim 1
additionally comprising at least one link member connected to said
housing and moveable responsive to rotatable movement of said
housing about said shaft.
26. The toroidal rotary damper apparatus according to claim 1
additionally comprising a moveable output member, a gear assembly
operatively associated with said moveable output member, said
housing and said shaft to multiply the motion ratio between said
shaft and said moveable output member.
27. The toroidal damper apparatus according to claim 15 wherein
said shaft defines fluid passageways in communication with said
chambers.
28. The toroidal rotary damper apparatus according to claim 26
wherein said gear assembly comprises a planetary gear assembly
affixed to said housing, a sun gear affixed to said shaft and
planetary gears operatively engaged with said output member.
29. The toroidal rotary damper apparatus according to claim 1
wherein said shaft has at least one shaft end extending outwardly
beyond said housing.
30. Toroidal rotary damper apparatus comprising, in combination:
housing defining a housing interior for containing damper fluid,
said housing interior at least partially formed by a toroidal inner
housing surface disposed about and spaced from an axis; a piston in
said housing interior having a curved outer peripheral piston
surface in substantially fluid-tight engagement with said toroidal
inner housing surface, spaced from said axis and disposed along a
common plane with said axis, said housing and said piston being
relatively rotatably movable about said axis; a fluid barrier
attached to said housing and positioned in said housing interior;
and a flow control passageway defined by either said piston or said
fluid barrier for permitting controlled passage of damper fluid
therethrough responsive to relative rotational movement between
said piston and said housing to dampen forces applied to the
toroidal damper apparatus causing said relative rotational
movement, said housing including two adjoining housing members,
each housing member defining a portion of said toroidal inner
housing surface, said toroidal rotary damper apparatus additionally
comprising connectors connecting together said housing members.
31. Toroidal rotary damper apparatus comprising, in combination: a
housing defining a housing interior for containing damper fluid,
said housing interior at least partially formed by a toroidal inner
housing surface disposed about and spaced from an axis; a piston in
said housing interior having a curved outer peripheral piston
surface in substantially fluid-tight engagement with said toroidal
inner housing surface, spaced from said axis and disposed along a
common plane with said axis, said housing and said piston being
relatively rotatably movable about said axis; a fluid barrier
attached to said housing and positioned in said housing interior; a
flow control passageway defined by either said piston or said fluid
barrier for permitting restricted passage of damper fluid
therethrough responsive to relative rotational movement between
said piston and said housing to dampen forces applied to the
toroidal damper apparatus causing said relative rotational
movement; and a shaft extending from said housing interior along
said axis and projecting outwardly from said housing, said shaft
being fixedly connected to said piston, said housing and said shaft
being relatively rotatably moveable, said housing including two
adjoining housing members, each housing member defining a portion
of said housing interior and further defining an opening receiving
said shaft, said shaft having spaced shaft end segments, a shaft
end segment extending outwardly from each of said openings and
disposed outside said housing, at least one of said shaft end
segments being a threaded shaft end segment, and said toroidal
rotary damper apparatus additionally including a nut threaded on
said threaded shaft end segment to maintain a connection between
said shaft and said housing.
Description
TECHNICAL FIELD
[0001] This invention relates to damper apparatus for dampening a
force, for example a force caused by relative movement between two
structural elements operatively associated with the damper
apparatus.
BACKGROUND OF THE INVENTION
[0002] Dampers are hydraulic devices used to restrict the number of
cyclic oscillations caused by a deflection force; damping forces
are generated by pumping fluid through regulating orifices,
converting kinetic energy into laminar and turbulent friction. Two
types of damping devices are currently in wide use; telescopic and
rotary vane type. Traditional van type rotary dampers have inherent
disadvantages, including the following:
[0003] 1. Hysteresis, due to disproportionate vane and shaft seal
pre-load; caused by means such as compression springs, Elastomers,
band springs or Elastomer Composites, resulting in frictional
losses and limited dynamic range;
[0004] 2. A rotary vane damper housing is subject to hoop stress,
compression deformation and bending strain at vane junctions,
causing excessive bypass flow and subsequent loss of compression;
and
[0005] 3. Thermal hysteresis due to non-uniform coefficient of
expansion; exasperated by long sealing contours of the vane and
structural components, leading to unpredictable sealing properties
at higher temperatures and friction at lower temperatures. This
limits the operating temperature range and diminishes the damping
characteristics during thermal cycles. Furthermore, such prior art
devices are hampered by their relative complexity, weight and high
cost.
[0006] The following U.S. patents disclose rotary dampers believed
to be representative of the current state of the prior art: U.S.
Pat. No. 4,926,984, issued May 22, 1990, U.S. Pat. No. 5,577,761,
issued Nov. 26, 1996, U.S. Pat. No. 5,324,065, issued Jun. 28,
1994, U.S. Pat. No. 4,886,149, issued Dec. 12, 1989, U.S. Pat. No.
5,400,878, issued Mar. 28, 1995, U.S. Pat. No. 5,381,877, issued
Jan. 17, 1995, and U.S. Pat. No. 6,296,090, issued Oct. 2,
2001.
[0007] Telescopic piston dampers are well known constructions
employing a pressurized chamber or cylinder having a piston movable
therein under controlled conditions and a piston rod associated
therewith to provide the transfer of dampening force. These
traditional-type dampers have certain fundamental drawbacks as
well. In such devices, due to the fact that the piston rod passes
through one end of the damper, there is a dynamic internal pressure
differential due to rod volume inclusion, necessitating measures to
counter the rod volume by either pressurizing the opposing chamber
by means of highly compressed gas and a dividing piston, as in a
monotube gas design, or a secondary chamber, via a foot valve, as
in the known double-tube design, or by inclusion of a complimentary
dummy shaft to equalize internal volume. All of the above measures
reduce damping efficiency, add cost, complexity and weight as well
as require substantial space.
[0008] Since telescopic dampers, to conform to non-linear
elasto-kinematics motion of the associate elements, are deployed
predominantly with translational mechanisms, they can not be
installed directly, or fixedly to a haul or a chassis. This
curtails the thermal conductance capacity of the damper and of the
fluid. Under severe operating conditions, fluid temperature can
rise to well over 100 degrees C., resulting in localized fluid
vaporization and creation of gas pockets, known as Cavitation. At
higher temperatures, damping forces diminish exponentially due to
fluid viscosity reduction, giving higher orifice discharge
coefficient. Also, conventional translational or linear dampers
have limitations when applied to long travel functions. It is
difficult to accommodate a large travel due to the danger of
bucking the damper shaft, especially at high relative velocities,
the linear space claim required by the length of a linear damper
can also create packaging problems.
[0009] Functionally, in order to achieve the desired damper
force-velocity characteristics, it is very difficult to adjust the
piston-valve; solutions such as a hollow piston rod containing an
internal shaft that performs the adjustments being very costly and
often incompatible with servo controls due to high torque demands.
Piston embedded servo valves are also complex, as well as reducing
the hydraulic capacity of the damper.
[0010] As described earlier, to adapt to non-linear and
elasto-kinematic requirements of the damping structures, telescopic
dampers are predominantly deployed via translational bushings,
excluding the possibility of direct attachment of damper to the
structures, hence impeding a heat transfer passage.
[0011] My U.S. Pat. No. 5,971,118, issued Oct. 26, 1999, discloses
a motion dampening apparatus which includes a damper housing
defining a curved damper housing interior for a fixed attachment to
a first structural member and a curved damper element for a fixed
attachment to a second structural member and movable within the
curved damper housing interior along a curved path of movement.
[0012] While the prior art indicated above does not teach or
suggest the combination of structural features disclosed and
claimed herein, it demonstrates the viability of the novel concept
of transition of a force-bearing piston within a radial or circular
structure; it also teaches the importance of fixed attachment of a
damper to its associate structural members resulting in a thermally
conducting pathway between a damper and a structure, as well as
eliminating the use of translational bushings from the damper
mounting points, which are also a source of parasitic friction.
DISCLOSURE OF INVENTION
[0013] The present invention relates to a toroidal rotary damper
apparatus which has a number of advantages over prior art damper
constructions. The toroidal rotary damper apparatus has excellent
sealing properties due to constant contact between a piston
employed in the apparatus and the interior of a toroidal shaped
housing. Due to symmetrical geometry of the piston and the
surrounding arcous interior, the piston or the shaft seals do not
require a pre-load force, this considerably reduces internal
friction and hysteresis. The apparatus has a low internal static
pressure and has a constant internal volume, eliminating the need
for a high pressure gas chamber or secondary expansion chamber to
compensate for an external rod.
[0014] The damping torque T generated by the toroidal rotary damper
is determined by volume of fluid displaced per angle of rotation
.theta., times the pressure drop across the piston .DELTA.P or:
T=.pi..theta..DELTA.PR.sup.2r.sup.2 where: .theta.=angle in radian,
.DELTA.P=pressure drop across the piston, R=radius of the toroid,
and r=radius of the damper piston.
[0015] The following relation converts rotary to linear motion:
x=2.pi.R.theta./360. The damping rate is determined by the rate of
change of .DELTA.P, or rate at which the damping fluid is allowed
to leak from the pressurized chamber across the piston orifices and
valves. Additionally, over a 90 degree sweep, mean toroidal volume
displacement is 5% larger, hence generating 5% more damping force,
than the equivalent linear displacement.
[0016] Furthermore, behavior of conventional telescopic damper is
well understood, comprehensive mathematical models and
fluid-dynamic simulations have been developed to analyze the
characteristics, since the toroidal rotary damper employs piston,
valving and cylindrical configuration substantially similar to that
of telescopic dampers, all relevant analysis are directly
applicable to the toroidal rotary damper system.
[0017] A toroidal rotary damper constructed in accordance with the
present invention operates according to the following operating
principle.
[0018] The apparatus has a wide dynamic damping range, approaching
340 degrees, as well as good thermal distribution due to a high
rate of fluid circulation and good thermal stability due to
efficient heat dissipation throughout the apparatus exterior. The
apparatus does not posses any inherent stress points due to
excellent load distribution of the piston surface area against the
interior of the torus.
[0019] The apparatus is relatively simple and low cost, also
providing the advantages of full external adjustability during
operation and ease of servicability due to the modular construction
thereof.
[0020] The damper apparatus is relatively compact and adapted for
installation even in restricted locations. The apparatus can accept
forces through a central shaft thereof or at locations on the
housing thereof and still effectively and efficiently provide
damping. Toroidal rotary damper may be configured either internally
within a suspension or a structure, or attached via a lever arm and
linkage. In addition toroidal rotary damper has smaller space
requirement, no exposed sealing surfaces and therefore more
resistance to debris and damage from foreign objects in harsh
environments.
[0021] The toroidal rotary damper apparatus of the invention
includes a housing defining a housing interior for containing
damper fluid, said housing interior at least partially formed by a
toroidal inner housing surface disposed about and spaced from an
axis.
[0022] The apparatus includes a piston in the housing interior
having a curved outer peripheral piston surface in substantially
fluid-tight engagement with the toroidal inner housing surface,
spaced from the axis and disposed along a common plane with said
axis. The housing and the piston are relatively rotatably moveable
about the axis.
[0023] A fluid barrier is fixedly attached to the housing and
positioned in the housing interior.
[0024] A flow control passageway (or control valve) is defined by
either the piston or the fluid barrier for permitting controlled
passage of damper fluid therethrough responsive to relative
rotational movement between the piston and the housing to dampen
forces applied to the toroidal rotary damper apparatus causing the
relative rotational movement.
[0025] Since the thermal expansion coefficient of the fluid is
larger than that of the metallic parts of the damper, in certain
applications, a low-pressure gas chamber or bladder could be
provisioned in the interior of the housing to absorb excessive
fluid pressure caused by thermal expansion, preventing formation of
gas or vapor bubbles in the fluid. Effectively functioning as a
temperature compensation mechanism.
[0026] Blow-off valves may also be incorporated in the piston or
the fluid barrier to limit the maximum transient pressure at higher
piston velocities, in order to avoid damage to the damper.
[0027] Other features, advantages and objects of the present
invention will become apparent with reference to the following
description and accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0028] FIG. 1 is a perspective view of an embodiment of toroidal
rotary damper apparatus constructed in accordance with the
teachings of the present invention;
[0029] FIG. 2 is a perspective view with a housing member of the
apparatus removed and illustrating interior structure of the
apparatus, including a piston and a fluid barrier;
[0030] FIG. 3 is an enlarged, cross-sectional view taken along the
line 3-3 in FIG. 2;
[0031] FIG. 4 is an exploded, perspective view illustrating
selected components of the toroidal rotary damper apparatus;
[0032] FIG. 5 is an enlarged, cross-sectional view taken along the
line 5-5 of FIG. 1;
[0033] FIG. 6 is a graphic representation showing force versus
velocity curves for various embodiments of the apparatus;
[0034] FIG. 7 is a view taken along the line 7-7 in FIG. 2, but
illustrating an alternative embodiment employing valves on the
piston;
[0035] FIG. 8 is a view similar to FIG. 7, but illustrating another
embodiment wherein valves are utilized on the fluid barrier of the
apparatus;
[0036] FIG. 9 is a view similar to FIGS. 7 and 8, but illustrating
yet another embodiment of the invention wherein two fluid barriers
are employed and two pistons are employed in the apparatus, each
piston having valves associated therewith with chambers
interconnected via fluid passageways through the central shaft;
[0037] FIG. 10 illustrates an embodiment of the invention wherein a
single fluid barrier is provided and operatively associated with
two pistons spaced from one another, the pistons incorporating
valves;
[0038] FIG. 11 illustrates an embodiment utilizing valve controls
to externally control operation of valves associated with a fluid
barrier;
[0039] FIG. 12 illustrates an embodiment of the device
incorporating a preload structure for pressurizing damper fluid in
the housing interior;
[0040] FIG. 13 is a view similar to FIG. 1, but illustrating an
alternative form of housing incorporating external connector
portions for connecting the housing to structural elements;
[0041] FIG. 14 illustrates the housing of FIG. 13 attached to two
spaced structural elements;
[0042] FIG. 15 illustrates an embodiment of the invention in which
the housing has elongated rods attached thereto, the apparatus
functioning as a rocker damper;
[0043] FIG. 16 is a view similar to FIG. 5, but illustrating a
plurality of flow control passageways formed in the piston;
[0044] FIG. 17 illustrates the use of toroidal rotary damper
apparatus of the present invention in association with a vehicle
suspension system and operating in the capacity of a lever
damper;
[0045] FIG. 18 illustrates the toroidal rotary damper apparatus
deployed axially with the pivoted support shaft of a vehicle
suspension system and affixed thereto;
[0046] FIG. 19 illustrates the toroidal rotary damper apparatus
utilized in a vehicle suspension system to accept tangential force
vectors using a push/pull rod and employed as a damped rocker
system;
[0047] FIG. 20 illustrates the toroidal rotary damper apparatus
incorporating a planetary gear assembly; and
[0048] FIG. 21 illustrates the toroidal rotary damper apparatus
integrated into an external housing structure.
MODES FOR CARRYING OUT THE INVENTION
[0049] Referring now to FIGS. 1-6, a toroidal rotary damper
apparatus constructed in accordance with the teachings of the
present invention is illustrated. The apparatus includes a housing
10 defining a housing interior 12 for containing damper fluid (not
shown) of any conventional nature. The housing interior has a
substantially circular cross section and is formed by a toroidal
inner housing surface 14 disposed about and spaced from a central
axis 16.
[0050] The housing 10 includes two adjoining housing members 18,
20, each housing member defining a portion of the housing interior
and further defining openings 22, 24, respectively, at the centers
thereof. Threaded fasteners 26 extending through holes in outer
flanges of the housing members are utilized to releasably secure
the housing members together.
[0051] A piston 30 having a substantially circular-shaped outer
peripheral piston surface at which is located an outer seal 32 is
in substantially fluid-tight, slidable engagement with the toroidal
inner housing surface, spaced from axis 16 and disposed along a
common plane with the axis 16. The housing 10 and the piston are
relatively rotatably moveable about the axis, as will be described
in greater detail below.
[0052] A fluid barrier 34 in the form of a plate is attached to the
housing and positioned in the housing interior.
[0053] The fluid barrier 34 defines multiple flow control orifices
or passageways 36 which permit restricted passage of damper fluid
therethrough responsive to relative rotational movement between the
piston 30 and the housing to dampen forces applied to the apparatus
causing the relative rotational movement.
[0054] A shaft 40 extends through the housing interior along axis
16 and projects outwardly from opposed sides of the housing, the
shaft passing through openings 22, 24 of the housing. A shaft end
segment extends outwardly of each of the openings and is disposed
outside the housing. Threads 42 are formed at two spaced locations
on the shaft and the shaft is threadedly engaged at those locations
by nuts 44. In the arrangement illustrated, one end 46 of the shaft
incorporates elongated, parallel projections to facilitate
connection of the shaft to other structure, if desired. The shaft
and nuts are rotatable as a unit relative to the housing. Washers
49 are disposed adjacent to nuts 44 and are slidable on shaft 40 to
provide a sliding or bearing interface between housing members 18,
20 and the shaft.
[0055] Piston 30 is secured to shaft 40 by radially protruding
member 48 affixed to shaft. In the embodiment illustrated,
elongated securement members 50 extending from member 48 are
disposed at opposed sides of the piston 30 to secure the piston to
member 48, it should be noted that piston 30 may be attached
fixedly to one or multiple securement members, or held unfixedly or
freely, from opposing directions, generally referred to as
"floating", in between securement members 50.
[0056] Relative rotational movement between the housing and the
piston about axis 16 will cause pressurized damper fluid in the
housing interior to pass through flow control passageways 36 and
thus dampen forces resulting in the relative rotational
movement.
[0057] A number of seals are employed in the apparatus to prevent
leakage of the pressurized damper fluid. A compression seal 54 is
installed in engagement with each of the housing members at the
location of member 48. At these locations, the compression seals
surround the shaft and maintain pressurization of damper fluid
within the housing interior. In addition, radial seals 56 and axial
seals 58 associated with each of the housing members and
surrounding the shaft act as fluid stops between the shaft and
housing to prevent possible leakage. It should be noted that radial
seal 56 may be deleted in some embodiments and applications if
sufficiently strong single or multiple axial seals 58 are
employed.
[0058] FIG. 7 illustrates an embodiment of the invention wherein
the housing 10A interior accommodates a fluid barrier 34A which has
no flow control valves formed therein. Instead, flow control valves
36A are located in piston 30A. In this arrangement, valves 60 which
may, as illustrated, be in the form of shim valves, or other
suitable hydraulic valves are attached to piston 30A and control
the fluid flow passageways 36A depending upon the relative
rotational direction of movement between the housing and
piston.
[0059] FIG. 6 illustrates a basic damper F(V) (Force versus
Velocity) graph calculated from the valve (or flow control
passageway) characteristics of the toroidal rotary damper apparatus
on the basis of study state analysis. For an open orifice damper,
the damping force can be considered as proportional to piston
speed, however, it is often desirable to include non-linear
properties in the damping curve.
[0060] The toroidal rotary damper apparatus can use different flow
control valve systems, such as the stacked-shims (spring plates) as
shown or spring-loaded ball valves to modify the damping
characteristics.
[0061] The graph of FIG. 6 illustrates F(V) damping characteristics
achieved by various valve applications:
[0062] Graph A-B. Highly progressive damping curves achieved by
various size open flow control passageways in the piston or fluid
barriers and
[0063] Graph C--Digressive damping curve achieved by stacked-shims
in the piston or fluid barrier.
[0064] FIG. 8 illustrates an embodiment employing valves 60B to
control damper fluid flow through flow control passageways formed
in the fluid barrier.
[0065] FIG. 9 illustrates an embodiment of the invention wherein
housing 10C accommodates therein two fluid barriers 34C fixed in
position within the housing interior and spaced from one another to
divide the housing interior into two separate chambers. Each of the
chambers accommodates a piston 30C therein. Valves 60C are
associated with each of the pistons.
[0066] Employing the arrangement of FIG. 9, each damping chamber
can be designed with different damping characteristics in mind,
e.g., one chamber can be solely dedicated to a compression cycle
while the other chamber can be for extension or to provide
intermediate or transitional damping characteristics. More than two
fluid barriers can be employed so that more than two chambers are
formed. The chambers can also contain fluids with different
properties (i.e. viscosity, density, thermal expansion, etc.) to
achieve desired final damping characteristics. Advantages are
better dynamic torque distribution within the damper and improved
thermal energy dissipation. Additionally, the opposing chambers can
be interconnected via fluid passageways 79 across the shaft,
effectively doubling piston surface area, hence doubling the
damping force.
[0067] In the arrangement of FIG. 10, a plurality of pistons 30D
(in this case two pistons) are affixed to the main rotating shaft
40D within the single chamber defined by fluid barrier 34D. This
divides the damping load between multiple pistons, with each piston
possibly having a specific damping characteristic. Advantages are
larger damping surface area and hence damping forces, better
dynamic torque distribution within the damper and improved thermal
distribution of the fluid.
[0068] FIG. 11 is a somewhat schematic presentation of an
embodiment of the apparatus having adjustable valves 60E utilized
to control flow through flow control passageways 36E.
[0069] Valve adjustments are provided to modify operation of the
damper, two different types of valve controls being shown. In one
embodiment of valve control mechanism an adjustment screw 66 is
associated with one of the valves 60E and may be threaded in or out
relative to the housing to control how far its associated valve can
be opened.
[0070] In the other valve control, a plunger 68 is associated with
a different valve mechanism 60E to change the position of a needle
valve. The plunger 68 extends from a servoactuator which may, for
example, be electric or hydraulic in nature. The servoactuator 70
is operatively associated with a control unit or CPU 72 managed by
discrete control strategies 74, adaptable during operation.
[0071] FIG. 12 discloses an embodiment wherein a housing 10F
accommodates a fluid barrier 34F and a piston 30F. Also disposed
within the housing interior is a low pressure preload structure for
pressurizing damper fluid in the housing interior for temperature
compensation, more particularly, a gas filled bladder 76. Damper
preload can be adjusted by changing the pressure of the pressurized
gas filled bladder.
[0072] FIG. 13 illustrates a housing 10G which includes enlarged
flange segments forming opposed connector portions 78 having
apertures 80 formed therein.
[0073] FIG. 14 shows the arrangement of FIG. 13 with the connector
portions 78 secured by bolts 82 to brackets extending from fixed
structural elements 84, 86. The shaft 40 and associated piston (not
shown in FIG. 14) rotate relative to the fixed housing to perform
the desired damping function.
[0074] FIG. 15 shows an embodiment wherein shaft 40 is attached to
brackets of a structural element 88 and fixed against rotation
relative thereto. In this arrangement, the housing 10I can rotate
in a reciprocal manner about the shaft, the apparatus functioning
as a rocker damper. Link members in the form of push-pull arms 90,
92 are connected to the housing 10I and reciprocally move fore and
aft as the housing rocks back and forth. The toroidal rotary damper
apparatus in this instance, due to its symmetrical geometry,
effectively behaves as a rocker damper for opposing force
vectors.
[0075] FIG. 16 illustrates a version of the toroidal rotary damper
apparatus which is the same in all respects as the embodiment of
FIGS. 1-5 except that the fluid barrier 34H is free of valves or
passageways and flow control passageways 36H are defined by piston
30H. In this embodiment no valves are employed to control flow
through the flow control passageways.
[0076] FIG. 17 illustrates a toroidal rotary damper apparatus A
constructed in accordance with the teachings of the present
invention employed in association with a vehicle suspension system
B as a lever damper, the link member or arm C of the toroidal
rotary damper apparatus A being connected to a pivoting link of the
vehicle suspension and also affixed to the central shaft 40 of the
apparatus. Housing 10 is fixed to the frame F of the vehicle.
[0077] FIG. 18 illustrates the housing 10 of toroidal rotary damper
apparatus A' constructed in accordance with the teachings of the
present invention affixed to the frame F of a vehicle. In this
instance, the apparatus A' is disposed axially with the elongated
element D of the suspension assembly which in turn is pivotally
mounted on the vehicle frame F and fixedly connected to the ends of
shaft 40 so that forces causing pivotal movement of the element D
and the rest of the assembly will be dampened by apparatus A'.
[0078] FIG. 19 shows a toroidal damper apparatus A'' wherein the
shaft 40 is affixed against movement to a vehicle frame F. The
housing 10 of the apparatus A'' rotates relative to the shaft and
the frame F. A link rod 94 interconnects the housing 10 to a
pivoted element 96 of the suspension so that the apparatus A''
functions as a shock absorber. This is representative of the fact
that the toroidal rotary damper apparatus can be utilized to accept
tangential force vectors using mechanisms like push-rods or
pull-rods effectively acting as a damped rocker system.
[0079] Referring now to FIG. 20, the housing 10J of a toroidal
rotary damper apparatus is affixed against movement. The apparatus
incorporates a moveable output member or lever 98 extending from a
planetary gear assembly associated with the housing. The assembly
includes a sun gear 100 affixed to shaft 40 of the apparatus. The
sun gear 100 is surrounded by planetary gears 102 which mesh with
the sun gear and with a ring gear 104 fixed in place externally of
housing 10J. The planetary gears are rotatably mounted at the inner
end of output member 98. This arrangement multiples the motion
ratio between the shaft 40 and the moveable output member 98, a
feature useful under certain circumstances, such as lever arm and
linkage applications.
[0080] FIG. 21 shows a toroidal rotary damper apparatus 10K
integrated into an external housing structure 110 where only the
shaft (shaft 112) protrudes from both sides of the housing. In this
embodiment the housing can be of solid material to increase
structural rigidity and thermal dissipation; or the housing can be
vacant. When vacant, the housing can function as an expansion
vessel to store and provide fluid; furthermore, in case of inner
shaft seal failure, space is provided to store fluid escaping
through the corresponding seal, which in turn can reduce the
internal pressure. This feature substantially increases reliability
and aids in prevention of contamination.
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