Note: Descriptions are shown in the official language in which they were submitted.
CA 02267974 1999-04-06
WINDOW REGULATOR PIVOT JOINT SUSPENSION SYSTEM
Field of Invention
This invention relates to a window regulator pivot joint suspension system.
Background of the Invention
Single arm regulator assemblies and cross arm window regulator assemblies are
well
known in the art and are used to control the operation of vehicle windows.
Most
commercial motor vehicles are provided with a plurality of vehicle windows
which are
slidably mounted to permit a range of independent vertical movement of each
vehicle
window bel:ween open and closed positions. Either type of window regulator
assembly can
be used to open and close a vehicle window, or to move a vehicle window
between any two
intermediate points within the range of travel of the window, or to hold a
stationary vehicle
window in an adjusted operating position within its range of travel.
Both types of window regulator assembly are im widespread use and both include
a
lift arm structure having a first end pivotally mounted to a fixed point on
the vehicle and a
second end pivotally secured to a slider or roller which is in turn slidably
engaged within a
substantially horizontal guide structure secured to the lower edge of the
vehicle window.
The cross arm regulator assembly adds a force balancing equalizer arm
structure pivotally
mounted to a central portion of the lift arm structure amd slidably mounted
using
conventional rollers or sliders between the horizontal guide structure on the
vehicle window
and a second horizontal guide structure mounted in a fixed position on the
vehicle.
The lift arm structure of each type of window regulator assembly is typically
pivotally secured to the fixed point on the vehicle through a pivot joint. The
structure of
conventional pivot j oints is a source of many problems in each type of window
regulator
assembly.
A sector gear is rigidly secured to the lift arm structure of each type of
window
regulator assembly which sector gear engages a pinion or worm gear which
transmits a drive
force from a power source to pivot the lift arm strucW re about the pivot j
oint to raise and
lower the window. Conventional pivot joint structure: requires the gearing in
both types of
assembly to be manufactured and installed within narrow tolerances.
Conventional pivot
j oint structure does a poor j ob of accommodating sector gear runout and a
poor j ob of
accommodating contact interference if the sector and pinion gears are mounted
too close to
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one another. Conventional pivot joints also provide little sound dampening
capability to
dampen the noise associated with gear movement when the pinion gear drives the
sector
gear to raise or lower the lift arm.
Most vehicle windows are curved about a longitudinal axis of curvature (where
S "longitudinal axis" refers to an axis which extends from the front of the
vehicle to the rear of
the vehicle and which is parallel to the ground). These curved windows
typically follow an
arcuate path when traveling between open and closed positions. This curvature
of the
vehicle window and of the path along which the vehicle window travels induces
stress in the
components of both the single arm and cross arm assemblies because each
assembly is
configured, because of the structure of the pivot j oint, to direct force
through the respective
lift arm thereof in an essentially vertical direction (eitlher upwardly or
downwardly,
depending on the pivotal direction of the lift arm and the structures
associated therewith),
but the vehicle window glass curvature causes transverse (i.e., side to side)
movement of the
respective lift arm structure as the window slides vertically. Conventional
pivot j oint
structures allow little if any freedom of movement of the lift arm structure
in the transverse
direction and are not well suited for operating and tracking curved vehicle
windows.
Conventional pivot j oints have other short comings. The maximum forces
exerted
on the pivot joint by the lift arm when raising and lowering the window can
become quite
high, depending on a number of factors such as the starting position of the
window, the
direction of travel of the vehicle window, the type and condition of the seal
structures used
with the window, whether the window is framed or frameless, the radius of
curvature of the
window, the presence of an obstruction, temperature, and humidity.
Conventional pivot
joints are not well suited to resisting wear associated with these momentary
high load forces
which occur during window operation. Furthermore, lift arm movement causes
both shear
forces on the pivot pin, which result when a vertical force is applied to the
window, and
bending forces which result from the above referenced transverse movements of
the lift arm
caused by the radius of curvature of the vehicle window.
Summary of the Invention
The disadvantages of the prior art may be overcome by providing a window
regulator assembly having a base structure and an arm pivotally mounted to the
base
structure. The base structure has an aperture. The arm has a pivot pin. A
resilient annular
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spacer is fitted within the aperture and about the pivot pin. The spacer urges
the arm to
maintain a spaced relation with the base structure.
It is desirable to provide a pivot joint suspension system for use in vehicle
window
regulator assemblies, including single arm regulator assemblies and cross arm
regulator
assemblies, which overcomes these and other technical problems associated with
convention
pivot joint design.
Brief Description of the Drawings
FIG. 1 is a cross-sectional view of a prior art pivot joint for a conventional
window
regulator showing a fragmentary portion of a lift arm pivotally mounted on a
base plate;
FIG. 2 is a fragmentary side elevational view showing a single arm regulator
assembly mounted in a vehicle door, operatively interconnected with a vehicle
window, and
incorporating a pivot joint suspension system according to the present
invention;
FIG. 3 is a fragmentary side elevational view showing a cross arm regulator
assembly mounted in a vehicle door, operatively interconnected with a vehicle
window, and
incorporating a pivot joint suspension system according to a second embodiment
of the
presentmventlon;
FIG. 4 is a fragmentary cross-sectional view o~f the pivot joint suspension
system
taken through the line 4-4 in FIG. 2;
FIG. 5 is a fragmentary cross-sectional view of the pivot joint suspension
system
taken through the line S-5 in FIG. 3;
FIG. 6 is an isolated perspective view of the flexible element showing a
plurality of
grease tracks and a plurality of lubricant grooves which are integrally formed
therein;
FIG. 7 is an enlarged fragmentary perspective view, partly in section, of the
flexible
element showing the structural details of the plurality of grease tracks and
the plurality of
lubricant grooves formed therein; and
FIG. 8 is an isolate perspective view of a base member for use with the pivot
joint
suspension system in a cross arm regulator assembly.
Detailed Description of the Preferred Embodiment
Referring now to the drawings there is shown therein in FIG. 1 an example of a
prior
art pivot joint, generally designated 10, for a window regulator assembly.
This prior art
pivot joint 10 is used to pivotally mount a lift arm structure of either a
single arm regulator
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assembly or a cross arm regulator assembly to a fixed point on a vehicle. A
lift arm of either
type of window regulator assembly is typically pivotally mounted to a fixed
point on a
vehicle by pivotally mounting the lift arm to a base wlhich is in turn secured
to the vehicle.
FIG. 1 shows an exemplary prior art pivot joint in which a pivot pin member 12
is secured
S to a fragmentary portion of a lift arm 14. The arm 14 has a circular edge 18
defining an
opening in the arm. The edge 18 is received within a groove of the pin member
12. The
groove is defined between a head portion 16 of the pivot pin member 12 and a
central
portion 20 of the pivot pin member 12. The central portion 20 is rotatably
received within
an aperture defined by an annular sleeve 22 stamped in a base plate 24 and is
held therein
by an enlarged end portion 26 of the pin member 12.
The base plate 24 is mounted within the vehicle in a conventional manner. The
base
plate 24 can be mounted, for example, to the vehicle door or could be mounted
on any
vehicle structural panel that allows mounting of a regulator arm assembly for
glass
movement. The base plate could, for example, be mounted on the rear inner
panel of a two
door vehicle or to a rear lift gate. The lift arm 14 pivots about an axis of
rotation defined by
the pin member 12 with respect to the base plate 24 to operate a vehicle
window.
It can be appreciated that an alternative embodiment of the prior art pivot j
oint 10
could be constructed in which the pivot pin member 12 is inverted and the lift
arm 14 is
provided with an annular sleeve similar to the annular sleeve 22 shown in FIG.
1. The base
plate 24 would have an opening similar to that formed by the circular edge 18
in FIG. 1.
The central portion 20 of the pivot pin member 12 would be rotatably disposed
within the
annular sleeve on the lift arm and held therein by the enlarged end portion 26
of the pivot
pin member. The pivot pin member in this alternativc: embodiment of the pivot
joint would
be fixed and stationary with respect to the base plate ''<?4 and the annular
sleeve incorporated
in the lift arm 14 would allow the rotation of the lift a.rm about the
stationary pivot pin
member 20.
As shown in FIG. 1, a clearance fit 27 is provided between the central portion
20 of
the pivot pin member 12 and the sleeve 22 in the base; plate 24. This
clearance fit in the
prior art pivot joint 10 allows only minimal movement of the lift arm 14
relative to the fixed
base plate 24 in the longitudinal direction (front to back of the vehicle).
This structure
provides no sound damping capability to reduce the noise associated with the
movement of
the intermeshed pinion and sector gears or the noise associated with the
movement of the
lift arm 14 when the associated vehicle window is raised or lowered.
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When used with either type of window regulator assembly, this prior art pivot
joint
is very dependent on manufacturing to accurate tolerance for sector gear
runout. If
tolerances are not accurate to within O.Omm (zero millimeters) to 0.3mm,
excessive meshing
noise between the sector gear and the pinion gear is generated during
operation of the
5 respective window regulator assemblies. This prior ao construction has no
structure
incorporated therein for reducing the vibrations normally associated with lift
arm 14
movement and this results in a reduced life span for both types of window
regulator
assembly.
The relative positions of the pinion gear and the sector gear are critical
when this
10 prior art structure is used in either type of window regulator assembly. If
the pinion gear is
too close to the sector gear, meshing noise and reduced life span of the
components of the
respective window regulator assembly can result. It can be appreciated that
this problem of
accurately positioning the pinion and sector gears with respect to one another
is
compounded by the above referenced problem of sector gear runout. The effects
of these
tolerances are additive.
The prior art pivot joint 10 allows relatively little transverse movement
(i.e., side to
side movement) of the end of the lift arm that is pivotally secured to the
window slider.
Thus, window tracking for curved windows is poor and the transverse movement
induced in
the lift arm 14 by the movement of the window results in component wear.
These technical problems associated with the prior art can be overcome by
replacing
the prior art pivot j oint 10 in a window regulator assembly with a pivot j
oint suspension
system which incorporates a resilient flexible element.
With reference to FIG. 2, there is shown a single arm window regulator
assembly,
generally designated 28. In FIG. 3 there is shown a cross arm window regulator
assembly,
generally designated 30. Each of these assemblies 28 and 30 include a pivot
joint
suspension system, generally designated 32 and 132, :respectively.
Referring now to FIG. 2, the single arm regulator assembly 28 is shown mounted
on
a vehicle door 34 and operatively interconnected with. a vehicle window 36.
The single arm
regulator assembly 28 includes a base structure 38 and a lift arm structure
40. The base
structure 38 is fixed in a conventional manner to an interior panel 42 of a
commercial motor
vehicle through fastener means such as bolt members 44, although any
conventional fastener
means could be used, including rivets. A first end of the lift arm structure
40 is pivotally
connected to a first end of the base structure 38 by a pivot pin structure 46
which is part of
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the pivot joint suspension system 32. A second end of the lift arm structure
40 is pivotally
connected to a conventional window regulator slide structure 48 through a
conventional
stud structure S0.
The slide structure 48 is slidably disposed within a window guide structure 52
which
is rigidly secured along the bottom edge of the vehiclf: window 36 through a
plurality of
bracket structures 54 or by any other means known in the art. The slide
structure 48, slide
structure SO and guide structure 52 thus cooperate to slidably and pivotally
mount the lift
arm structure to the vehicle window 36. The vehicle window 36 is slidably
engaged in a
conventional manner with a pair of parallel, generally, vertical track
structures (not shown)
which are mounted within the vehicle door 34 to forms the travel path of the
vehicle window
36.
A sector gear structure 56 is rigidly secured to the lift arm structure 40.
Sector gear
teeth 58 are formed on gear structure 56 and engage pinion gear teeth 60
formed on a
pinion gear structure 62. The pini on gear structure 62 i s mounted on a drive
shaft which i s
bi-directionally driven by an electric motor in an electric drive assembly
(not shown). Teeth
58 are shown on two edges of the sector gear structure 56, including on a
concave edge not
in contact with the pinion gear structure 62. These teeth on the concave edge
result from
the fact that a plurality of sector gear structures are curt contiguously from
a sheet of metal
material. It can be appreciated that because the base structure 38 is rigidly
secured to the
panel 42, that the lift arm structure 40 pivots with respect to the base
structure 38 about a
pivot axis formed by the pivot pin structure 46, which is part of the pivot
joint suspension
system 32.
The operation of the single arm regulator assembly 28 is well known. To raise
or
lower the vehicle window 36, the motor assembly rotates the pinion gear
structure 62 on the
drive shaft which arcuately displaces the sector gear structure 56 in a well
known manner
causing the lift arm structure 40 to pivot about the pivot pin structure 46
arcuately upwardly
or downwardly depending on the rotational direction of the drive shaft. This
pivoting of the
lift arm structure 40 moves the associated slide structi.cre 48 to slide
within the guide
structure 52 so as to apply a vertical force to the vehicle window 36 to
advance the same
upwardly or downwardly along the pair of conventional side track structures
which form the
travel path of the window 36. The lift arm structure 40 also acts as a support
structure to
hold a stationary vehicle window 36 in an adjusted operating position when the
motor drive
shaft stops rotating.
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The cross arm regulator assembly 30 shown in FIG. 3 includes a base member 72
secured to an interior panel 142 of a vehicle door 134 by bolt members 144 or
by any other
conventional means, and a lift arm member 74 pivotally attached to the base
member 72 by a
pivot pin structure 146 in the pivot joint suspension system 132. A distal end
of the lift arm
member 74 is pivotally secured to a window slide structure 148 through a stud
structure
150. The slide structure 148 is slidably disposed within a guide structure 152
mounted
along a lower edge of the vehicle window 136.
An equalizer arm member 76 is pivotally attached to a central portion of the
lift arm
member 74 by a conventional connector rivet member 78. One end of the
equalizer arm
member 76 is slidably engaged with the guide structure 152, and the other end
is slidably
engaged with a lower guide structure 80 mounted on t:he vehicle door. A stud
structure 158
is rigidly attached to each end of the equalizer arm member 76 and each stud
158 is pivotally
engaged with a slide structure 149 slidably disposed within respective the
guide structures
152, 80. The lower guide structure 80 is secured to the vehicle door panel by
bolt members
145; one skilled in the art will appreciate that the guide structure 80 can be
secured to the
door panel by any conventional means, including rivets.
A sector gear member 82 is rigidly secured to the proximal end of the lift arm
member 74, and the sector gear teeth 84 on gear member 82 engage the pinion
gear teeth 86
on the pinion gear member 88. The pinion gear member 88 is mounted to the
drive shaft of
the a motor assembly (not shown to better illustrate the invention) for
rotation therewith.
The motor assembly is mounted in a conventional manner to the base member 72.
The operation of the cross arm regulator assembly 30 is well known in the art.
A
motor assembly (not shown) drives the pinion gear member 88 which causes the
arcuate
displacement of the sector gear member 82. This causes the lift arm member 74
to pivot
about pivot pin structure 146 in the pivot joint suspension system 132. The
pivoting of the
lift arm member 74 moves the slide structure 148 associated therewith within
track 152
arcuately upwardly downwardly (the direction depending on the rotational
direction of the
pinion gear member 88). The pivotal movement of the lift arm member 74
simultaneously
causes pivotal movement of the equalizer arm 76 about rivet 78, causing slide
member 149
to be slid along guide structures 158, 80. This creates the application of a
vertical force of
the vehicle window 136 to effect the upward or downward movement of the
vehicle
window 136. As the lift arm member 74 pivots aboul: the pivot pin structure
146, the
equalizer arm member 76 moves with a scissors-type action by pivoting about
the connector
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rivet member 78 as the slide structures 149 at each end thereof slide through
their respective
guide structures 152, 80. The equalizer arm member '76 and the lift arm member
74 coact in
a well known manner to apply a balanced force to the vehicle window 136, which
helps
maintain the guide structure 152 parallel to the ground (assuming the vehicle
is parked on a
level surface).
It can be appreciated by one skilled in the art that the single arm and cross
arm
regulator assemblies 28, 30 illustrated above could also be manually driven by
a hand crank
or similar device mechanically connected to drive the pinion gear structure 62
or the pinion
gear member 88.
FIG. 4 is a cross-sectional view of the pivot joint suspension system 32 shown
in
FIG. 2. The suspension system 32 includes a pivot pin structure 46 having a
head portion
92 extending through an aperture 90 in the lift arm structure 40 to pivotally
mount the lift
arm structure 40 on base structure 38. A resilient flexible spacer element 94
surrounds a
middle portion 96 of the pivot pin structure 46. An integral disk-shaped
portion 98 of the
1 S pivot pin structure 46 prevents the axial displacement of the flexible
spacer element 94 in a
direction away from the lift arm structure 40. The flexible spacer element 94
and the middle
portion 96 of pivot pin structure 46 extend through a base aperture 100
defined by a
cylindrical flange 102 integrally formed with the base: structure 38. A
circular ridge 104
formed on the lift arm structure 40 provides a low frictional engagement
surface between
the lift arm structure 40 and the base structure 38 to facilitate the rotation
of the former with
respect to the latter.
A conical surface 106 surrounding the sleeve or flange 102 on the base
structure 38
is normally maintained in spaced relation with respect to a facing conic
surface 108 on the
lift arm structure 40 by the flexible spacer element 94. The flexible spacer
element 94 is
resiliently compressible and thus permits relative movement between the base
structure 38
and the lift arm structure 40. It can be appreciated that the relative
movement of the base
structure 38 and lift arm structure 40 in a direction perpendicular to the
longitudinal axis of
the pivot pin structure 46 is limited primarily by the compressibility of the
flexible element
94 and secondarily by contact between the two conic surfaces 106, 108.
It can be appreciated that the flexible spacer element 94 eliminates vibration
in the
stationary single arm and sector regulator assembly 28 and provides a number
of benefits
when the sector gear structure 56 and the pinion gear structure 62 are rotated
and the
vehicle window 36 is displaced. For example, the relative positions of the
pinion gear and
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the sector gear is frequently too close when the prior art pivot joint of FIG.
1 is used in a
single arm regulator which results in meshing noise and reduced service life
of the gears and
other parts of the assembly. The pivot joint suspension system 32 overcomes
this problem
by providing sufficient relative movement between the pinion gear structure 62
and the
sector gear structure 56 via compression of flexible spacer element 94 to
prevent contact
interference between the structures 56, 62. In addition, the flexible element
94 also allows
greater tolerance stack up due to manufacturing tolerances in the sector gear
structure 56
and the pinion gear structure 62 by allowing the lift arm structure 40 and the
sector gear
structure 56 to flex and absorb any movements generated by gear meshing.
Furthermore,
noise generated during gear meshing is dampened by the flexible spacer element
94.
The flexible spacer element 94 also extends the service life of the assembly
28 by
reducing the maximum loads experienced by the assembly 28 components. It is
well known
that the load on the lift arm structure 40 can vary greatly depending on a
number of factors.
Momentarily high loads can be placed on the assembly 28 due to static
frictional forces,
1 S gravity, and other factors when window movement is initiated with a
stationary position.
High loads can also be caused by an obstruction, ice, or by the window
reaching the upper
or lower limit of its travel path. The flexible element 94 reduces the peak
load on the
electric motor, the lift arm structure 40, the base structure 3 8, the slide
structure 48, and
other assembly components by permitting a degree of relative movement between
the base
structure 38 and the lift arm structure 40 in any direction in the plane
perpendicular to the
longitudinal axis of the pivot pin structure 46, including the vertical
direction and in the
longitudinal (horizontal) direction.
This flexible element 94 also improves glass curvature tracking by permitting
greater
transverse movement of the end of the lift arm structi;~re 40 pivotally
connected to the slide
structure 48.
Although the embodiment of the pivot j oint suspension system 32 shown in FIG.
4 is
preferably used in the single arm regulator assembly :?8 of FIG. 2, this
embodiment shown in
FIG. 4 can also be used in the cross arm regulator assembly 30 of FIG. 3.
The pivot joint suspension system 132 of the cross arm regulator assembly 30
of
FIG. 3 is shown in cross-section in FIG. 5. This suspension system 132 can be
used in the
single arm regulator assembly 28 as well.
With reference to FIG. 5, the suspension system 132 includes a pivot pin
structure
146 having a head portion 192 extending through an aperture 110 in the lift
arm member 74
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and an opening 112 in the base member 72 to pivotally mount the lift arm
structure 74 on
the base member 72. The opening 112 in base member 72 is surrounded by a
cylindrical
wall portion 114 of the base member 72. The flexible: spacer element 194 is
disposed
between the base member 72 and the middle portion 196 of the pivot pin
structure 146. The
disk-shaped portion 98 of the pivot pin structure 46 prevents the axial
displacement of the
flexible spacer element 194 in a direction away from the lift arm member 74.
The head
portion 192 and the disk-shaped portion 198 of the pivot pin structure 146
hold the base
member 72 and the lift arm member 74 in rotational contact.
FIG. 8 shows an isolated view of the base member 72 for the cross arm
regulator
assembly 30. The base member 72 is a one piece, stamped metal or molded
plastic structure
which includes the cylindrical wall portion 114 which surrounds the opening
112, and
further includes a motor shaft opening 124 which is formed at the top of a
raised portion
126 of the base member 72. A plurality of attachment apertures 128 are formed
on each of
a plurality of lateral flange structures 130 which extend outwardly from
integral side wall
portions 132 of the base member 72. When the base member 72 is secured to the
panel 142
(shown in fragmentary view in FIG. 3 but not shown in FIG. 8), the flange
structures 130
are held against the panel 142 by conventional threaded fasteners which extend
through the
respective attachment aperture 128 and through aligned openings (not shown) in
the panel
142. Each threaded fastener threadedly engages a bolt member 144. The shaft of
the motor
assembly extends through the shaft opening 124 and supports the pinions gear
member 88
above a top surface 134 of the raised portion 126. The lift arm member 74 (not
shown in
FIG. 8) is mounted on an upper surface 136 of the base member 72 with the
pivot pin
structure 146.
It can be appreciated that there is no structural engagement between the base
member 72 and the lift arm member 74 that prevents the relative movement of
the members
72, 74 in a direction perpendicular to the longitudinal axis of the pivot pin
structure 46. It
will be recalled with reference to FIG. 4 that contact between conical
surfaces 106 and 108
in the embodiment illustrated therein restricts this movement. It can
therefore be
appreciated that the embodiment in FIG. 4 can handle; relatively higher loads
than the
embodiment of FIG. 5.
All the benefits discussed with the embodiment of FIG. 4 accrue with the
embodiment of FIG. 5.
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The flexible element 94 or 194 can be manufactured from many materials having
a
range of durometers that can accommodate a range of sector gear to pinion gear
engagements (i.e., a wide range of contact interferenc:e). Dupont HytrelTM
having a 50
Shore A durometer and Urethane having either a 50 or 60 Shore A durometer can
be used.
Softer materials having a 35-40 Shore A durometer can also be used and would
further
reduce noise and improve gear running engagement.
The flexible element 94 (or 194) is shown in isolation in FIG. 6 and a portion
thereof
is shown in fragmentary perspective view in FIG. 7. The bearing surfaces of
the flexible
element 94 include a plurality of annular tracks and grooves to retain
lubricant. The top and
bottom surfaces 115 and 116, respectively, thereof are provided with grease
tracks 118; an
inner cylindrical surface 120 thereof is provided with a plurality of inner
lubricant grooves
122. The cylindrical surface 120 comprises the bearing surface for the pivot
pin structure
46. Many lubricants can be used with the flexible element 94 including
silicone, Teflon
PTFE, impregnated oil or molybdenum disulfide.
It will be thus seen that the obj ects of the present invention have been
fully and
effectively accomplished. It will be realized, however, that the foregoing
preferred specific
embodiment has been shown for the purpose of illustrating the functional and
structural
principles of the present invention and is subject to change without departure
from such
principles. Therefore, the present invention includes all modifications
encompassed within
the spirit and scope of the following claims.
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