U.S. patent application number 11/342061 was filed with the patent office on 2006-07-06 for low-friction moving interfaces in micromachines and nanomachines.
This patent application is currently assigned to General Nanotechnology LLC. Invention is credited to Victor B. Kley.
Application Number | 20060147131 11/342061 |
Document ID | / |
Family ID | 33100637 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060147131 |
Kind Code |
A1 |
Kley; Victor B. |
July 6, 2006 |
Low-friction moving interfaces in micromachines and
nanomachines
Abstract
A low-friction device having a moving interface comprising first
and second members. Each of the members has a maximum dimension of
about 100 .mu.m or less between any two points. At least the first
member is formed of diamond and the first and second members are in
sliding contact or meshing contact.
Inventors: |
Kley; Victor B.; (Berkeley,
CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
General Nanotechnology LLC
Berkeley
CA
|
Family ID: |
33100637 |
Appl. No.: |
11/342061 |
Filed: |
January 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10925866 |
Aug 24, 2004 |
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11342061 |
Jan 27, 2006 |
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10094149 |
Mar 7, 2002 |
6802646 |
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10925866 |
Aug 24, 2004 |
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60287677 |
Apr 30, 2001 |
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Current U.S.
Class: |
384/42 |
Current CPC
Class: |
Y10T 74/18736 20150115;
B81B 5/00 20130101; F16C 33/043 20130101; Y10S 977/724 20130101;
Y10S 977/902 20130101; F16C 11/0619 20130101 |
Class at
Publication: |
384/042 |
International
Class: |
F16C 33/00 20060101
F16C033/00 |
Claims
1. A low-friction device having a moving interface, the
low-friction device comprising first and second members wherein:
each of the members has a maximum dimension of about 100 .mu.m or
less between any two points; at least the first member is formed of
diamond; and the first and second members are in sliding contact.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 10/925,866 filed Aug. 24, 2004, which is a
continuation application of U.S. application Ser. No. 10/094,149
filed Mar. 7, 2002, which claims priority from the following
provisional application, the entire disclosures of which are
incorporated by reference in their entirety for all purposes:
[0002] U.S. Application No. 60/287,677, filed Apr. 30, 2001 by
Victor B. Kley for "Scanning Probe Microscopy and
Nanomachining."
[0003] The following six U.S. patent applications, were filed
concurrently with U.S. application Ser. No. 10/094,149 and the
disclosure of each other application is incorporated by reference
in its entirety for all purposes: [0004] U.S. patent application
Ser. No. 10/093,842, filed Mar. 7, 2002 by Victor B. Kley for
"Nanomachining Method and Apparatus"; [0005] U.S. patent
application Ser. No. 10/094,411, filed Mar. 7, 2002 by Victor B.
Kley for "Methods and Apparatus for Nanolapping";
[0006] The following U.S. patents are incorporated by reference in
their entirety for all purposes: [0007] U.S. Pat. No. 6,144,028,
issued Nov. 7, 2000 to Victor B. Kley for "Scanning Probe
Microscope Assembly and Method for Making Confocal,
Spectrophotometric, Near-Field, and Scanning Probe Measurements and
Associated Images;" [0008] U.S. Pat. No. 6,252,226, issued Jun. 26,
2001 to Victor B. Kley for "Nanometer Scale Data Storage Device and
Associated Positioning System;" [0009] U.S. Pat. No. 6,337,479,
issued Jan. 8, 2002 to Victor B. Kley for "Object Inspection and/or
Modification System and Method;" and [0010] U.S. Pat. No.
6,339,217, issued Jan. 15, 2002 to Victor B. Kley for "Scanning
Probe Microscope Assembly and Method for Making Confocal,
Spectrophotometric, Near-Field, and Scanning Probe Measurements and
Associated Images." [0011] U.S. Pat. No. 6,752,008, issued Jun. 22,
2004 by Victor B. Kley for "Method and Apparatus for Scanning in
Scanning Probe Microscopy and Presenting Results"; [0012] U.S. Pat.
No. 6,787,768, issued Sep. 7, 2004 by Victor B. Kley and Robert T.
LoBianco for "Method and Apparatus for Tool and Tip Design for
Nanomachining and Measurement". [0013] U.S. Pat. No. 6,802,646,
issued Oct. 12, 2004 by Victor B. Kley for "Low Friction Moving
Interfaces in Micromachines and Nanomachines"; and [0014] U.S. Pat.
No. 6,923,044, issued Aug. 2, 2005 by Victor B. Kley for "Active
Cantilever for Nanomachining and Metrology";
[0015] The disclosure of the following published PCT application is
incorporated by reference in its entirety for all purposes: [0016]
WO 01/03157 (International Publication Date: Jan. 11, 2001) based
on PCT Application No. PCT/US00/18041, filed Jun. 30, 2000 by
Victor B. Kley for "Object Inspection and/or Modification System
and Method."
BACKGROUND OF THE INVENTION
[0017] This application relates generally to micromachines and
nanomachines and more specifically to devices providing
low-friction rotational and translational interfaces for
micromachine and nanomachine contacts.
[0018] Micromachines and nanomachines are poised to solve
mechanical problems at the molecular and atomic level. Such
machines may solve problems in environments were other devices,
such as electronic devices, fail. For example, microscale
mechanical memories may be of use in environments, such as space,
in which semiconductor based devices have high fault rates due to
high-energy cosmic radiation. Further, microscale mechanical
machines may be of surgical use, reaching areas of the body not
otherwise accessible or manipulable by traditional surgical tools
and techniques.
[0019] At small scale, for example in the hundreds and tens of
micron range and below, mechanical elements exhibit problematic
behavior that either 1) does not arise or 2) is of little
consequence at relatively larger scale. For example, meshed gears
in macroscale machines do not tend to exhibit problems due to
stiction, which is the sticking and fusing of different elements or
portions of elements into a union. However, at smaller scale, such
problems can arise.
[0020] Lithographic techniques have been deployed to make
relatively small mechanical devices, for example, relatively small
gears etched from silicon wafers. However, such relatively small
silicon gears have a tendency to stick and fuse to each other. If
such gears are in mechanical motion when stiction between the gears
occurs, the gears may gall each other or worse tear each other
apart.
[0021] Lubricants have been applied to relatively small mechanical
interfaces in an attempt to limit friction, stiction, and galling.
However, like solid bits of matter of relatively small scale,
liquids at relatively small scale also exhibit problematic behavior
that would be of little consequence at relatively larger scale. For
example, surface tension causes relatively small quantities of
liquid to form small droplets that tend not to flow across a
surface, thus limiting a lubricant's effectiveness.
[0022] Consequently, new microscale and nanoscale devices are
sought which provide for improved performance.
BRIEF SUMMARY OF THE INVENTION
[0023] In accordance with the invention low-friction moving
interfaces in micromachines and nanomachines include low-friction
sliding interfaces. In one aspect of the invention, a device has
first and second members in sliding contact. Each the members has a
maximum dimension of about 100 .mu.m or less between any two points
and one of the first and second members is formed of diamond. In
another aspect of the invention, a device has a toothed member and
a tooth-engaging member in meshing contact. Both the toothed member
and tooth-engaging member have dimension of about 100 .mu.m or less
between any two points and one of the toothed member and
tooth-engaging member is formed of diamond.
[0024] A further understanding of the nature and advantages of the
present invention may be realized by reference to the remaining
portions of the specification and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a graph of the temperature of a diamond-silicon
dynamic interface for a relatively small diamond according to a
mathematical model of the interface;
[0026] FIG. 2 is an overall perspective view of a mechanical device
having a low-friction moving interface according to an embodiment
of the present invention;
[0027] FIG. 3 is a schematic cross-sectional view of another
mechanical device having a low-friction moving interface according
to another embodiment of the present invention;
[0028] FIG. 4 is a schematic cross-sectional view of another
mechanical device having a low-friction moving interface according
to another embodiment of the present invention;
[0029] FIG. 5 is a schematic cross-sectional view of another
mechanical device having a low-friction moving interface according
to another embodiment of the present invention; and
[0030] FIG. 6 is an overall perspective view of another mechanical
device having low-friction moving interfaces according to an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Introduction
[0031] The following description sets forth embodiments of
low-friction moving interfaces in micromachines and nanomachines
according to the invention. Embodiments of the invention can be
applied to sliding and/or meshing mechanical contacts.
[0032] Diamond is a very slippery crystal. Diamond in mechanical
contact with crystals such as diamond itself or silicon exhibits
relatively low-frictional heating and has a tendency not to fuse
with itself or silicon. Further, the flash temperature of
diamond-silicon interfaces is relatively high. The flash
temperature is that at which bodies in frictional contact tend to
gall each other. The flash temperature of various interfaces can be
estimated by taking into account, for example, the speed at which
surfaces move with respect to each other and the forces at the
interface. For example, see "Tribology and Mechanics of Magnetic
Storage Devices," publisher Springer, pp. 366-411, by Bhushan in
which a general formalism is developed to calculate flash
temperatures.
[0033] FIG. 1 is a graph of a mathematical modeling of the
temperature of a dynamic diamond-silicon interface at various
interface forces and velocities. The diamond-silicon interface
modeled is that of a diamond rod having a flat circular end sliding
across a planar piece of silicon. The diameter of the flat circular
end of the rod is about 50 nm at the interface. As indicated by the
graph, the temperature of the diamond and silicon forming the
interface rises from frictional heating as the force and/or
velocity of the diamond and silicon increase. Pinnacle 110 at the
top right of the graph represent the flash temperature of the
interface. As can be seen, the flash temperature, is between
900.degree. C. and 1000.degree. C. The interface force of the
diamond on silicon at the flash temperature is between 275
millinewtons and 300 millinewtons and the velocity of the surfaces
relative to each other is about 500 millimeter/second. Forces and
velocities in these ranges are relatively high indicating the
general durability of the interface. While the graph represent only
a single geometric interface of diamond and silicon in frictional
contract, an impetus is created for the manufacture of
diamond-silicon mechanical interfaces of relatively small
scale.
[0034] Described below are various embodiments where two members
engage each other in different ways, referred to as sliding contact
and meshing contact. These types of interaction will be defined
below in connection with the specific embodiments. In these
embodiments, both of the members may be diamond or one of the
members may be diamond with the other being, for example, silicon,
quartz, a III-V material such as gallium arsenide, and the like.
While substances such as silicon and gallium arsenide are of
limited mechanical use at macroscale dimensions (e.g. greater than
1 millimeter) due to their fragility, such substances suffer less
from fragility at relatively smaller scales, (e.g. 100 .mu.m). At
such small scales, each of the aforementioned materials in such
contact with diamond provides for devices that have relatively low
friction and are relatively mechanically sound. Further, each of
the aforementioned materials has a relatively high flash
temperature in sliding contact with diamond, for example, as high
as 900.degree. C. and above. Thus at normal operating temperature,
(e.g., 300.degree. C.) such materials tend not to gall each
other.
Embodiments Having Sliding Contact
[0035] A "sliding contact" is defined herein as a first member that
is in dynamic frictional contact with a second member, such that
the first member and second member have surfaces that are in smooth
continuous contact.
[0036] FIG. 2 is an overall perspective view of a mechanical device
200 having a low-friction moving interface 210 according to an
embodiment of the present invention. The mechanical device includes
a first member 215 that has a circular aperture 222. Portions of
the aperture are indicated in phantom view. The aperture has a
surface denoted by reference numeral 225. The mechanical device
includes a second member 250 in the shape of a spindle having a
rounded surface 252, portions of which are shown in phantom. As
shown, the second member is fitted into the aperture. Low-friction
moving interface 210 is identified as the areas at which the
aperture surface and the second member are in sliding contact. The
first member and second member may have a rotational degree of
motion with respect to each other (as indicated by double-headed
arrow 262), a translational degree of motion with respect to each
other (as indicated by double-headed arrow 268), or both.
[0037] First member 215 and second member 250 may each be a single
or multicrystalline structure. For example, first member 215 may be
a single diamond crystal or a polycrystalline diamond.
[0038] The first and second members may be fabricated using a
variety of techniques. For example, a member comprising silicon may
be etched from a silicon wafer using known lithographic techniques
or may be cut from a silicon wafer using cutting and sweeping
techniques discussed in the above referenced U.S. patent
application for "Nanomachining Method and Apparatus," Attorney
Docket No. 020921-001430US. Alternatively, a member comprising
silicon may be formed by lapping techniques such as those discussed
in the above referenced U.S. patent application for "Methods and
Apparatus for Nanolapping," Attorney Docket No. 020921-001450US.
Each of these fabrication techniques is similarly applicable to
diamond members, quartz members, and the like. Those of skill in
the art will know of other useful fabrication techniques.
[0039] First member 215 may be coated into the aperture of another
device such as a disk. A first member so positioned is commonly
referred to as a bushing. For example, a first member comprising
diamond may be coated into an aperture in a silicon disk. A first
member so positioned may be formed, for example, by first forming a
diamond-like carbon layer in the aperture and second growing a
diamond onto the diamond-like carbon layer. Diamond-like carbon may
be coated into an aperture via a vacuum arc process or via ion-beam
techniques and grown using plasma-enhanced chemical vapor
deposition. Those of skill in the art will know other useful
coating processes for diamond-like carbon. Diamond can also
subsequently be grown onto the diamond-like carbon in a
diamond-anvil cell or other high-pressure device.
[0040] According to a specific embodiment of the invention, each of
the first and second members has a maximum dimension of about 100
.mu.m or less between any two points. According to another
embodiment, each of the first and second members has a maximum
dimension of about 5 .mu.m or less between any two points.
[0041] FIG. 3 is a schematic cross-sectional view of a mechanical
device 300 having a low-friction moving interface 310 according to
another embodiment of the present invention. The mechanical device
includes a first member 315 that has a round socket 322, which is
defined by surface 326. Mechanical device 300 includes a second
member 350 that has an arm portion 352 and a ball end 354. The ball
end of the second member is in sliding contact with surface 326.
Such a configuration is commonly referred to as a ball-and-socket
joint.
[0042] For consistency and clarity, a particular coordinate system
will be shown and referred to. FIG. 3 is considered to lie in the
x-y plane, and the z-axis will be considered to extend out of the
page. In accordance with standard symbology, an axis extending out
of the page will be denoted by a dot in a circle while an axis
extending into the page will be denoted by a + in a circle. The
cross-sectional view of FIG. 3 thus shows mechanical device 300
extending laterally in the x-y plane. In most instances, references
to direction and orientation that mention an axis (e.g., the
x-axis) or a plane (e.g., the x-y plane) should be considered to
include lines parallel to that axis, or planes parallel to that
plane
[0043] First and second members 315 and 350 may have a variety of
rotational degrees of motion with respect to each other, for
example, member 350 may rotate relative to member 315 about the
z-axis, the x-axis, or any axis laying between the z and
x-axes.
[0044] FIG. 4 is an overall perspective view of a mechanical device
400 having low-friction moving interfaces 410 according to an
embodiment of the present invention. The mechanical device includes
a first member 415 in the shape of a plate, and a second member 420
having a slot 422. A portion of first member 415 is inserted into
slot 422. The first member spins such that portions of its surfaces
423 and 425 are in sliding contact with surfaces 427 and 429,
respectively.
[0045] According to a specific embodiment of the invention, each of
the members has a maximum dimension of about 100 .mu.m or less
between any two points. According to another embodiment, each of
the members each has a maximum dimension of about 5 .mu.m or less
between any two points. First and second members 410 and 420 may be
fabricated by a variety of processes such as those described above
for the fabrication of mechanical device 200 shown in FIG. 2.
[0046] Mechanical devices having components (e.g., diamond plate
and silicon slotted member) providing low-friction translational
contact are deployable for a variety of tasks. For example,
mechanical device 400 may be of use as a fluid pump. The
low-friction moving interface can drag a fluid between ends of the
slot, thus providing pumping. Further, such a device, made of say
diamond and silicon or diamond and diamond, provides for tremendous
translational rates. For example, a diamond plate in a silicon slot
of the dimension discussed above may be turned at millions or more
revolutions per second prior to reaching the flash temperature.
[0047] Each of devices 200, 300, and 400 may be bearing type
devices, wherein one of the members provide support, guidance, and
reduces the friction of motion between the other member and moving
or fixed machine parts (not pictured in FIG. 2, 3, or 4). Other
moving or fixed machine parts may include, for example, a housing
(e.g., a journal box) containing one of the devices, or additional
members in sliding contact devices 200, 300, and 400.
Embodiments Having Meshing Contact
[0048] A "meshing contact" is defined herein as a "toothed member"
being in frictional contact with a "tooth-engaging member," such
that the toothed member meshes with the tooth-engaging member to
transmit motion or to change direction or speed.
[0049] FIG. 5 is a schematic cross-sectional view of a mechanical
device 500 having a low-friction moving interface 510 according to
another embodiment of the present invention. The mechanical device
includes a gear 515 (an example of a toothed member) that has a
plurality of gear teeth 520 and includes a rack 550 (an example of
a tooth-engaging member) that has a plurality of gear teeth 555. As
shown, gear teeth 520 and gear teeth 555 are in meshing contact.
Mechanical device 500 provides for two types of motion: (a) the
rack may be moved laterally along the x-axis causing the gear to
rotate about the z-axis, or (b) the gear may be rotated causing the
rack to be translated. Translation device 560 coupled to rack 550
may provide such translations of the rack. Translation device 560
may include a variety of devices, such as, piezoelectric
transducers, thermal expansion/contraction devices, mechanical
actuators, and the like. Further, such translation devices may be
coupled to both ends of the rack for further control.
[0050] While rack 550 is shown to have teeth that extend beyond the
region where the gear and rack mesh, the teeth may extend a lesser
amount, for example, the teeth may be limited to the region where
the gear and rack mesh.
[0051] According to a specific embodiment of the invention, each of
the gear and rack has a maximum dimension of about 100 .mu.m or
less between any two points. According to another embodiment, each
of the gear and rack has a maximum dimension of about 5 .mu.m or
less between any two points. Gears and racks made of materials such
as those discussed may be fabricated by a variety of processes such
as those described above for the fabrication of mechanical device
200 shown in FIG. 2.
[0052] FIG. 6 is a schematic cross-sectional view of a mechanical
device 600 having a low-friction moving interface 610 according to
another embodiment of the present invention. The mechanical device
includes a gear 615 (an example of a toothed member) that has a
plurality of gear teeth 620 and includes a worm gear 650 (an
example of a tooth-engaging member) that has a thread 655. As
shown, gear teeth 620 and thread 655 are in meshing contact.
Mechanical device 600 provides for two types of motion: (a) worm
gear 650 may be rotated about the x-axis causing gear 615 to rotate
about the z-axis, or (b) gear 615 may be rotated about the z-axis
causing the worm gear to rotate about the x-axis.
[0053] Both the gear and/or rack shown in FIG. 5 and the gear
and/or worm gear shown in FIG. 6 may be coupled to a devices 200,
300, or 400 shown in FIGS. 2, 3, and 4. For example, the second
member 252 (FIG. 2) having a spindle shape may be coupled to the
center of rotation of gear 515 and/or worm gear 550. Both gear 610
and worm gear 650 have similar maximum dimension as those of gear
510 and rack 550 shown in FIG. 5 and can be fabricated by similar
methods.
CONCLUSION
[0054] While the above is a complete description of specific
embodiments of the invention, various modifications, alternative
constructions, and equivalents by be used. For example,
diamond-silicon, diamond-diamond, and the like may be variously
configured while still providing low stiction, low galling, and
relatively high flash temperature devices. For example, device 200
may have a first member 215 that has a trench instead of an
aperture in which the second member is in sliding contact. Further,
diamond-silicon, diamond-diamond, and the like meshing interfaces
may include, for example, gear on gear interfaces in addition to
gear on rack/worm gear interfaces. Therefore, the above description
should not be taken as limiting the scope of the invention a
defined by the claims
* * * * *