Abstract
An inspection system is used to view an image of the inside diameter
(ID) of an engine bearing. The inspection system includes a stationary
line scan camera, a pivoting mirror, a scanning mirror and a stationary
mount. The engine bearing is placed in the stationary mount such that
the bearing remains motionless throughout the entire scanning process.
The light line generator produces a light line that initially contacts
a beam splitter. The beam splitter then guides the light line onto
the pivoting mirror, which then directs the light line onto one of
a pair of stationary mirrors and then finally onto the scanning mirror.
The scanning mirror will sweep the light line across a portion of
the engine bearing ID surface. The light line will generate reflected
images of the ID surface. These reflected images will return along
the light line's path; however, instead of being directed back into
the light line generator by the beam splitter, the reflected images
will pass through the beam splitter. Once the reflected images pass
through the beam splitter, they will journey through the lens and
into the stationary line scan camera. From the stationary line camera,
the reflected images can be viewed on a monitor and recorded for future
use.
Claims
What is claimed is:
1. An inspection system for inspecting an inside diameter (ID)
surface of a component, comprising: a mount configured to hold the
component in a first fixed position during a scanning interval;
optics configured to direct a source light beam to said ID surface
wherein an image beam is produced; and a line scan camera disposed
in a second fixed position configured to acquire said image beam.
2. The system of claim 1 wherein said optics comprise: a first
mirror moveable between a first position and a second position;
a scanning mirror moveable from a start orientation to a stop orientation;
said first mirror in said first position configured to direct said
source light beam to said scanning mirror via a first stationary
mirror, said scanning mirror configured to scan said ID surface
using said source light beam when moving from said start orientation
to said stop orientation.
3. The system of claim 2 wherein said start and stop orientations
are first start and stop orientations, said scanning mirror further
having second start and stop orientations, said first mirror in
said second position being configured to direct said source light
beam to said scanning mirror via a second stationary mirror, said
scanning mirror being configured to scan said ID surface when moving
from said second start orientation to said second stop orientation,
an area of said ID surface scanned by said scanning mirror via said
second stationary mirror different from that scanned by said scanning
mirror via said first stationary mirror.
4. The inspection system of claim 1 wherein said line scan camera
has a line of sight coincident with a main viewing axis.
5. The inspection system of claim 3 wherein said first and second
stationary mirrors are symmetric about said main viewing axis.
6. The inspection system of claim 1 wherein respective rotating
axes of said first mirror and said scanning mirror are parallel.
7. The inspection system of claim 1 further including a light line
generator configured to generate said source light beam, said source
light beam comprising a light line.
8. The inspection system of claim 7 wherein said light line generator
is centered about a main viewing axis
9. The inspection system of claim 7 wherein a rotating axis of
one of said first mirror and said scanning mirror is parallel to
said source light beam.
10. The inspection system of claim 1 wherein said optics further
include a beam splitter configured to facilitate the overlapping
of the path taken by the source light beam and the path taken by
the image beam.
11. The inspection system of claim 10 further including a lens.
12. The inspection system of claim 11 wherein said lens has a principal
axis that is coincident with said main viewing axis.
13. The inspection system of claim 3 wherein said first and second
stationary mirrors are configured to direct said image beam of said
component to said first mirror and said beam splitter.
14. The inspection system of claim 1 further including means for
recording said image beam.
15. The inspection system of claim 3 further including a control
device configured to control and coordinate movements of said first
mirror and said scanning mirror.
16. The inspection system of claim 15 further including means for
analyzing said image beam for predetermined characteristics.
17. A method for inspecting an exemplary component for imperfections
comprising the steps of: affixing an exemplary component to a stationary
mounting platform; generating at least one light line; directing
said at least one light line onto a first highly reflective surface
that pivots between a first position and a second position; further
directing said at least one light line onto a second highly reflective
surface which scans between at least two pre-determined positions;
directing said image beam onto said second highly reflective surface;
further directing said image beam onto said first highly reflective
surface; and viewing said image beam with a stationary line scan
camera.
18. The method of claim 17 further comprising the step of directing
said at least one light line onto a first of a pair of stationary
highly reflective surfaces.
19. The method of claim 17 further comprising the step of scanning
said at least one light line across at least one portion of an exemplary
component.
20. The method of claim 17 further comprising the step of generating
an image beam of a surface of said exemplary component.
21. The method of claim 17 further comprising the step of directing
said image beam onto a second of a pair of stationary highly reflective
surfaces.
22. The method of claim 17 further comprising the step of symmetrically
aligning said first position and said second position of said first
highly reflective surface.
23. The method of claim 17 further comprising the step of rotating
said second highly reflective surface such that said second highly
reflective surface scans at least one additional portion of said
exemplary component.
24. The method of claim 17 further comprising the step of directing
said light line onto at least one additional highly reflective surface.
25. The method of claim 17 further comprising the step of directing
said image beam onto at least one additional highly reflective surface.
26. The method of claim 17 further comprising the step of directing
said light line onto at least one beam splitter.
27. The method of claim 17 further comprising the step of directing
said image beam onto at least one beam splitter.
28. The method of claim 17 further comprising the step of directing
said image beam onto at least one additional highly reflective surface.
29. An inspection system for imaging a component comprising: image
acquisition means for acquiring an image beam corresponding to an
exemplary component; light source means for producing an illumination
beam; and optics means for directing said illumination beam to an
inside diameter (ID) surface of said exemplary component wherein
image beam is reflected therefrom, said optics beam further configured
to direct said image beam to said image acquisition means, wherein
said image acquisition means and said exemplary component are stationary
during a scanning interval.
30. The system of claim 29 wherein said optics include a beam splitter,
a pivoting mirror, a scanning mirror and a pair of stationary mirrors,
said pivoting mirror having a first position configured to direct
said illumination beam to said scanning mirror and said image beam
from said scanning mirror via a first one of said pair of stationary
mirrors, said pivoting mirror being movable from said first position
to a second position configured to direct said illumination beam
to said scanning mirror and to direct said image beam from said
scanning mirror via the second one of said pair of stationary mirrors.
31. The system of claim 30 further including a controller configured
to direct movement of said pivoting mirror between said first and
second positions.
32. The system of claim 30 further including a controller configured
to direct movement of said scanning mirror.
33. The system of claim 29 wherein said image acquisition means
include a lens, a stationary line scan camera and a display monitor
wherein said lens magnifies and focuses said image beam as needed,
said stationary line scan camera processes said image beam and said
display monitor provides means for viewing said image beam.
34. The system of claim 33 further including a means for recording
said image beam.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
application Ser. No. 60/227,538 filed Aug. 24, 2000, herein incorporated
by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to an inspection
system, and more particularly, to an engine bearing inspection system
and to a method to inspect engine bearings.
[0004] 2. Description of the Related Art
[0005] In motor vehicles, engine bearings serve to withstand the
immense mechanical loads generated by crankshaft movement and to
protect the crankshaft journals from physically contacting the engine
block. Because of the tremendous loads on the inner diameter (ID)
surface of these engine bearings, the ID surfaces must remain free
from impurities and defects, such as dust, scratches and chips at
all times, including during their own manufacturing process. Currently,
bearing manufacturers inspect the ID surfaces for defects and impurities
with human inspectors. Because of high production demands, manufacturers
typically produce eighty bearings every minute. Because of this
high throughput, it is not possible for the human inspectors to
inspect every bearing for impurities or defects. To increase the
numbers of bearings inspected, bearing manufacturers have attempted
to inspect the ID surfaces with imaging technology. Conventional
inspection approaches have shortcomings.
[0006] One approach taken to inspect an inside diameter surface
in the context of a can includes using at least three cameras to
view the entire ID surface as seen by reference to U.S. Pat. No.
5,699,152 issued to Fedor et al. The expense incurred in using at
least three cameras exemplifies an obvious flaw with the approach
taken in Fedor et al. Another flaw caused by using multiple cameras
(such as in Fedor et al.), in general, involves the generation of
internal reflections. Internal reflections are caused by the use
of multiple light sources in the imaging process that generate internal
reflections, for example within the concave-shaped bearing. The
internal reflections, in turn, generate undesirable dark strips
on the resulting images of the ID surface. The dark strips will
prevent the imaging system from detecting impurities or defects
located on these obscured portions of the ID surface images.
[0007] Another imaging technology method used to inspect ID surfaces
utilizes a single camera. Yet in order to view the bearing in its
entirety, either the camera or the bearing under inspection must
move to perform a complete scan of the entire surface ID. Moving
the bearing slows throughput because extra time must be allotted
for the bearing's motion and the extra movement exposes the bearing
to an increased risk of damage. Likewise, moving the camera to scan
the bearing also slows throughput because extra time must be allotted
for the camera's motion. Furthermore, in order for the camera to
move, the system requires long cables to power and operate the camera.
These long cables generate electromagnetic interference that reduces
the image quality of the inspection system. Also, the repetitive
movement of the camera causes premature wear or breakage of the
camera cables. This wear or breakage usually results in the costly
replacement of the camera cables.
[0008] These disadvantages have made it apparent that a new technique
to inspect engine bearings for impurities or defects is needed.
SUMMARY OF THE INVENTION
[0009] One object of the present invention is to provide a solution
to one or more of the above mentioned problems. One advantage of
the present invention is that only one camera is needed to acquire
the image beam of the inside diameter (ID) surface of a component
under inspection such as an engine bearing. Another advantage of
the present invention is that the camera remains stationary, thereby
eliminating the possibility of excessive wear, breakage and tangling
of the camera cables. Another advantage of the present invention
is the elimination of internal reflection interference in the resulting
image, compared to conventional multi-camera, multi-light source
arrangements. Another advantage of the present invention is that
the component under inspection remains stationary throughout the
scanning process, thus reducing the possibility of damaging the
component by excessive movement. Still another advantage of the
present invention is that an increased percentage of engine bearings
can be inspected for impurities and defects without decreasing throughput.
[0010] In one aspect of the invention, an inspection system is
provided that is used to view an image of an inside diameter (ID)
surface of a component, such as an engine bearing. The system includes
a mount, optics, and a line scan camera. The mount is configured
to hold the component in a first fixed position during a scanning
interval. The optics are configured to direct a source light beam,
such as a light line, to the ID surface wherein an image beam is
produced. The line scan camera is disposed in a second fixed position,
and is configured to acquire the image beam so produced. The component
under inspection and the line scan camera are both stationary during
the scanning interval, thereby reducing or eliminating one or more
of the problems as set forth in the Background.
[0011] In a preferred embodiment, the optics comprise a first mirror,
and a scanning mirror. The first mirror is moveable between a first
position and a second position, while the scanning mirror is moveable
from a first start orientation to a first stop orientation. The
first mirror, which may be a pivoting mirror, when in the first
position, is configured to direct the source light beam to the scanning
mirror by way of a first stationary mirror. The scanning mirror
is configured to scan a portion of the ID surface using the source
light beam when moving from the first start orientation to the first
stop orientation.
[0012] In a still further preferred embodiment, the scanning mirror
further includes a respective second start and stop orientation.
The first mirror, when in the second position, is configured to
direct the source light beam to the scanning mirror by way of a
second stationary mirror. The scanning mirror is configured to scan
the remainder of the ID surface of the component under inspection
when moving from the second start orientation to the second stop
orientation. In a constructed embodiment, the area of the ID surface
scanned by the scanning mirror by way of the first stationary mirror
is about one-half the total area, while that scanned by the scanning
mirror by way of the second stationary mirror comprises the other
half.
[0013] A method for inspecting a component is also presented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will now be described by way of example,
with reference to the accompanying drawings, in which:
[0015] FIG. 1 is a side view of a first embodiment of an inspection
system in accordance with the present invention, shown in a first
position for scanning a first half of the bearing;
[0016] FIG. 2 is a perspective view of an engine bearing, showing
an inside diameter (ID) surface;
[0017] FIG. 3 is a side view of the inspection system of FIG. 1
in a second position for scanning the other half of the bearing;
[0018] FIG. 4 is a timing diagram illustrating the movement and
respective speed profiles of the pivoting and scanning mirrors;
[0019] FIG. 5 is a side view of an alternate embodiment of an inspection
system in accordance with the present invention wherein a light
source is centered about the bearing under inspection; and
[0020] FIG. 6 is yet another embodiment of an inspection system
according to the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0021] In the following figures, the same reference numerals identify
identical components in the various views. FIG. 1 illustrates an
inspection system 10 according to the present invention. System
10, in one embodiment, is particularly suited for inspection of
components used in an automotive environment. However, the present
invention may also be applied to various other uses that may require
an inspection system, including inspection of other parts having
an inside diameter (ID) surface.
[0022] Referring to FIG. 1, a side view of an inspection system
10 in accordance with one embodiment of the present invention is
illustrated. System 10 is configured for inspecting a component
having an inside diameter (ID surface). In the illustrated embodiment,
such component comprises an engine bearing, particularly one-half
of a split type main bearing. One skilled in the art will realize
that system 10 may include one representation of many possible systems
to inspect an engine bearing. The component to be inspected, such
as engine bearing 12 (best shown in FIG. 2), may be placed symmetrically
with respect to a viewing axis 14 on a stationary mounting platform
16. One skilled in the art, however, will realize that engine bearings
are merely one type of many possible components that can be inspected
using system 10. In addition, one skilled in the art will realize
that engine bearing 12 can be positioned asymmetrically relative
to axis 14, depending upon which portion of engine bearing 12 requires
inspection.
[0023] FIG. 1 also depicts a light line generator 18 configured
to produce a light line 20, and an optics system 22. Optics system
22 includes a beam splitter 24, a pivoting mirror 26, a pair of
stationary mirrors 28.sub.1, 28.sub.2 that are symmetrically positioned
about viewing axis 14, and a scanning mirror 30. FIG. 1 further
illustrates an image beam 32, an image acquisition means 34 comprising
a lens 36 and a stationary line scan camera 38, a display monitor
40 and a control module 42 that houses the logic to drive generator
18 and control various components of optics system 22.
[0024] Referring to FIG. 2, a perspective view of engine bearing
12 is shown. Axis C is the cylindrical axis of engine bearing 12.
An engine bearing ID surface 44 is the surface of engine bearing
12 that is scanned by system 10 for imperfections such as, but not
limited to, scratches, nicks, chips, lint or dirt. Light line 20
is also shown in diagrammatic fashion.
[0025] Referring again to FIG. 1, generator 18 is configured to
produce light line 20 for illuminating the ID surface 44 of bearing
12. In the illustrated embodiment, generator 18 is controlled by
control module 42 to activate and create light line 20. One skilled
in the art will realize that generator 18 may include one of a plurality
of light sources that can be used in conjunction with system 10.
Types of light sources include, but are not limited to, laser, optical
fiber or focused light. The type of light used depends upon, among
other factors, the type and shape of the component being inspected.
Generator 18 is positioned in a manner such that light line 20 is
directed to beam splitter 24.
[0026] Optics system 22 is configured generally to direct a source
light beam from generator 18 to the ID surface 44 wherein the image
beam 32 is produced. Optics 22 includes a beam splitter 24 that
is centered on axis 14 wherein axis 14 coincides with the center
of engine bearing 12. Once light line 20 reaches beam splitter 24,
light line 20 will be directed to pivoting mirror 26.
[0027] Pivoting mirror 26 is centered on axis 14. Pivoting mirror
26 is moveable between a first position and a second position. In
the illustrated embodiment, controller 42 is configured to move
pivoting mirror 26 to the first position to scan a first half (i.e.,
the right hand side) of the bearing, and, to further move mirror
26 to its second position to scan the other half of ID surface 44
(i.e., the left hand side). It should be appreciated that pivoting
mirror 26 may comprise one of a plurality of highly reflective surfaces
known to those of ordinary skill.
[0028] Stationary mirror 28.sub.1 and mirror 28.sub.2 can be any
one of a plurality of highly reflective surfaces known to those
of ordinary skill.
[0029] Scanning mirror 30 can be substituted with any one of a
plurality of highly reflective surfaces, as one skilled in the art
will realize. Scanning mirror 30, in a preferred embodiment, is
positioned such that its rotating axis A is parallel to the rotating
axis of pivoting mirror 26, namely rotating axis B. Scanning mirror
30 is moveable so as to sweep from a first start orientation to
a first stop orientation, and to further sweep from a second start
orientation to a second stop orientation. Scanning mirror 30 has
an axis of rotation, designated "A," that is preferably
coincident with the cylindrical axis "C" of the component
(e.g., bearing 12). This will be described in greater detail below.
[0030] In general operation, the pivoting mirror 26, when in the
first position, is configured to direct the source light beam (i.e.,
light line 20) to the scanning mirror 30 by way of first stationary
mirror 28.sub.1. Scanning mirror 30 is configured to scan the ID
surface 44 using the source light beam, namely light line 20, when
the scanning mirror is moved via controller 42 from the above-mentioned
first start orientation through to the above-mentioned first stop
orientation. In one embodiment, this action scans one-half of the
bearing. Pivoting mirror 26, in its second position, is configured
to direct the source light beam, namely light line 20, to scanning
mirror 30 via second stationary mirror 28.sub.2. The scanning mirror
30 is configured to scan the ID surface 44 when it is moved under
control of controller 42 from its second start orientation through
to its second stop orientation using the source light beam.
EXAMPLE
[0031] In the embodiment of FIG. 1, for purposes of facilitating
description, the twelve o'clock position may be taken as the 0-degree
reference, with increasing degree values to be taken in the clockwise
(CW) direction. Pivoting mirror 26 initially faces about 45-degrees;
however, this direction can be altered as needed. Again using the
12 o'clock position as the 0-degree reference, scanning mirror 30
is initially positioned in a first start orientation, which is at
81 degrees in the present embodiment. That is, the mirror is positioned
so that a light line 20 is redirected to about an 81 degree position,
relative to a 12 o'clock position being 0 degrees.
[0032] The first start orientation thus provides a starting point
for scanning mirror 30 to scan the right side of ID surface 44.
[0033] After controller causes mirror 26 and mirror 30 to assume
the positions/orientations described above, it causes generator
to be activated and produce light line 20. After light line 20 reaches
pivoting mirror 26, it will be directed to stationary mirror 28.sub.1.
From stationary mirror 28.sub.1, light line 20 will travel to scanning
mirror 30. Light line 20, when it leaves scanning mirror 30, will
travel to and contact the engine bearing inside diameter (ID) surface
44 at approximately 90-degrees.
[0034] While scanning mirror 30 is controlled to rotate clockwise,
it will redirect light line 20 in a clockwise scanning motion. When
light line 20 scans ID surface 44, an image beam 32 of ID surface
44 is generated. Image beam 32 initially will retrace light line's
20 path. Image beam 32 travels from the ID surface 44 and strikes
scanning mirror 30. Scanning mirror 30 guides image beam 32 to stationary
mirror 28.sub.1, which in turn directs image beam 32 to pivoting
mirror 26. Unlike light line 20, however, beam splitter 24 will
not divert image beam 32. Instead, image beam 32 will pass through
beam splitter 24 and into lens 36. Lens 36 can magnify and focus
image beam 32 if needed. Once past lens 36, image beam 32 will travel
to stationary camera 38, where it may be acquired, and, thereafter
processed by either (i) image processing software in control module
42 or (ii) by an operator using display monitor 40 and be recorded
for later analysis. Both lens 36 and stationary camera 38 may be
centered on axis 14. Further, one skilled in the art will realize
that recording can be accomplished by many methods including, but
not limited to, electronically or magnetically. Scanning mirror
30 will continue rotating clockwise under control of control module
42 until reaching the first stop orientation. In the first stop
orientation, light line 20 is directed by mirror 30 to the 180-degree
reference. The scanning mirror 30 itself is rotated about 47 degrees.
[0035] Referring to FIG. 3, once the right side of engine bearing
12 is scanned completely, system 10 is ready to commence scanning
the left side of the engine bearing 12. Controller 42 controls the
initialization of optics system 22 (e.g., to initial or start orientations)
the light generator 18, and image acquisitions means 34. To effect
scanning of the left side as viewed in FIGS. 1 and 3, controller
42 causes pivoting mirror 26 to rotate from its first position (i.e.,
the 45-degree position) to its second position (i.e., 315-degree
position). One skilled in the art will realize that the first position
and the second position of pivoting mirror 26 do not have to be
at 45- and 315-degrees, respectively, so long as the two positions
used are symmetric with respect to the 0-degree axis. Controller
42 will further cause scanning mirror 30 to rotate from its prior
position where it directed light line 20 to the 180-degree position
(i.e., where it finished its first scan) to a position where it
will direct light line 20 to an approximately 284-degree position.
This will mark the second start orientation for scanning the remainder
of bearing 12. Once 30 pivoting mirror 26 and scanning mirror 30
are initialized for scanning the left side, as described above,
the scanning process begins again, this time with scanning mirror
30 being controlled to travel in a clockwise (CW) direction, again
for about 47 degrees, until it reaches its second stop orientation
(i.e., where the light line 20 is directed to an approximately 180-degree
position). Once the scan of the left side of engine bearing 12 is
complete, both scanning mirror 30 and pivoting mirror 26 return
to their original positions, as described above.
[0036] Referring to FIG. 4, a timing diagram illustrating the time
required for scanning mirror 30 and pivoting mirror 26 to complete
a full scanning cycle is shown. Also shown is the rpm profile of
scanning mirror 30 and pivoting mirror 26 through their various
positions. Control module 42 houses the logic necessary to command
the operation of motors used in moving mirrors 26 and 30. It takes
system 10 approximately 0.25 seconds to move scanning mirror 30
and pivoting mirror 26 into their initial start positions at 81-degrees
and 45-degrees respectively; however, one skilled in the art will
realize that the amount of time system 10 takes to initialize scanning
mirror 30 and pivoting mirror 26 depends upon other system components,
such as the type of motor used. During this time, the rpm profiles
of scanning mirror 30 and pivoting mirror 26 reach their first peak
at approximately 200 rpm.
[0037] One skilled in the art will realize that other rpm values
can be used in conjunction with system 10 as dictated by the components
used. Once the scan of the right side of engine bearing 12 begins,
the rpm output of pivoting mirror 26 is zero because pivoting mirror
26 is stationary during scanning. The speed of scanning mirror 30
drops down to 40 rpm to complete the scanning motion. The scan of
the right side of engine bearing 12 takes approximately 0.2 seconds,
yet one skilled in the art will realize that this value depends
upon the components used and also can be altered as needed. However,
the foregoing being said, the improvement occasioned by the present
invention results from keeping both the camera and the component
stationary. This allows the improved scanning speed referred to
above. Once the scan of the right side of engine bearing 12 is complete,
scanning mirror 30 and pivoting mirror 26 are initialized once again
in preparation for the scan of the left side of engine bearing 12.
In 0.1 second, the motors will place scanning mirror 30 in the 284-degree
position and pivoting mirror 26 in the 315-degree position the respective
start orientations for the left hand side scan. During this initialization,
the rpm values once again achieve their maximum value at approximately
200 rpm. From this initial position, the rpm value for pivoting
mirror 26 again drops to zero because pivoting mirror 26 does not
move during the scanning process. Similarly, the rpm value for scanning
mirror 30 drops to 40 rpm during the scan of the left side of engine
bearing 12. In 0.2 seconds, the scan of the left side of engine
bearing 12 is complete.
[0038] Referring to FIG. 5, an alternative embodiment of an engine
bearing inspection system designated 110 is presented. Instead of
being stationed directly above engine bearing 12, stationary camera
38 and lens 36 are positioned off to the side while generator 18
assumes the position above engine bearing 12. In this embodiment,
light line 20 will flow through beam splitter 24 onto pivoting mirror
26. From pivoting mirror 26, light line 20 will be directed as described
in reference to FIGS. 1-3 above. Image beam 32 also will follow
the same general trajectory as described in reference to FIGS. 1
and 2 above, except that beam splitter 24 will direct image beam
32 into lens 36, where it then travels to stationary camera 38.
[0039] Referring to FIG. 6, yet another alternative embodiment
of an engine bearing inspection system, herein designated 210, is
illustrated. A first mirror 46, as described in reference to FIGS.
1-3 above, replaces beam splitter 24. In addition, two light line
generators 48.sub.1, 48.sub.2 are symmetrically mounted above first
mirror 46 such that the generated light lines 50.sub.1, 50.sub.2
do not contact the first mirror 46. One skilled in the art will
realize that a single light line generator can be used as long as
the generated light line is symmetrically wider on both sides than
first mirror 46. Light lines 50.sub.1, 50.sub.2 will flow through
first mirror 46 and contact pivoting mirror 26. From pivoting mirror
26, light lines 50.sub.1, 50.sub.2 will proceed as described in
reference to FIGS. 1 and 2 above. Image beam 32 will also be directed
as described in reference to FIGS. 1 and 2 above except that instead
of bypassing beam splitter 24, image beam 32 will be guided by first
mirror 46 into the lens 36.
[0040] Those skilled in the art will appreciate that the source
light path and the image path can be rearranged so that the specific
example values provided above may vary. For instance, in an alternative
embodiment, the source lighting and imaging paths may be slightly
different so that the pivoting mirror 26 faces a 42.12 degree direction
and a 317.88 degree direction, instead of a 45 degree direction
and 315 degree direction, respectively, in preparation for right
hand side and left hand side scans of bearing 12. In addition, it
should be understood that scanning mirror 30 is located at, and
rotates with respect to a cylindrical axis, or best fitted cylindrical
axis, of a full, semi, partial, or near cylindrical part surface
being inspected. That is, the cylindrical axis C of the bearing
12 (or best fit axis of any particular part) is substantially coincident
with the axis of rotation A of the scanning mirror 30. In addition,
it will be further appreciated that in the embodiments described
herein, that the path taken by the source light beam and the path
taken by the image beam are substantially identical from the ID
surface 44 all the way to beam splitter 24. Moreover, those of ordinary
skill in the art will appreciate that there exists no perfect cylindrical
surfaces and reasonable tolerances should be given to the meanings
of "identical" and "perpendicular," as described
herein.
[0041] Further, those skilled in the art shall vision the applications
of the invented system in parts with cylindrical ID surfaces other
than engine bearings, such as, but not limited to, the cylinder
bores in internal combustion engines.
[0042] The invented system, wherever necessary, can be reduced
to scan a portion of an engine bearing, or a part of the like, with
only one of the stationary mirrors, the scanning mirror. In this
case, the light will be directed directly from the beam splitter
to the stationary mirror, without passing through the pivoting mirror.
[0043] From the foregoing, it can be seen that a new and improved
inspection system for engine bearings has been brought to the art.
It is to be understood that the preceding description of the preferred
embodiments is merely illustrative of some of the many specific
embodiments that represent applications of the principles of the
present invention. Other arrangements would be evident to those
skilled in the art without departing from the scope of the invention
as defined by the following claims. |