Title: Driven pulley system with spring positioner
Abstract: A driven pulley system for use in a torque converter of a vehicle is disclosed. The driven pulley system includes relatively axially movable first and second flanges arranged to squeeze a belt of the torque converter therebetween. The driven pulley system also includes a spring positioner that includes a worm gear and a worm arranged to rotate the worm gear to wind or unwind a spring to cause relative axial movement between the first and second flanges to adjust the squeeze of the belt by the first and second flanges.
Patent Number: 6,994,643 Issued on 02/07/2006 to Kalies
| Inventors:
|
Kalies; Ken Edward (Richmond, IN)
|
| Assignee:
|
Hoffco/Comet Industries (Richmond, IN)
|
| Appl. No.:
|
438414 |
| Filed:
|
May 15, 2003 |
| Current U.S. Class: |
474/46; 474/8 |
| Current Intern'l Class: |
F16H 53/08 (20060101) |
| Field of Search: |
474/8,10,11,12,14,17,19,20,21,32,46
192/52,54,93.A
|
References Cited [Referenced By]
U.S. Patent Documents
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| |
| 2612054 | Sep., 1952 | Davis.
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| 2658399 | Nov., 1953 | Mercier.
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| 2928286 | Mar., 1960 | Davis.
| |
| 2987934 | Jun., 1961 | Thomas.
| |
| 3103999 | Sep., 1963 | Rabinow et al.
| |
| 3545580 | Dec., 1970 | Baer.
| |
| 3625079 | Dec., 1971 | Hoff.
| |
| 3747721 | Jul., 1973 | Hoff.
| |
| 3824867 | Jul., 1974 | Brooks.
| |
| 3850050 | Nov., 1974 | Lemmens.
| |
| 3895544 | Jul., 1975 | Suzaki.
| |
| 4179946 | Dec., 1979 | Kanstoroom.
| |
| 4196641 | Apr., 1980 | Vogel.
| |
| 4380444 | Apr., 1983 | Dolza.
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| 4575363 | Mar., 1986 | Burgess et al.
| |
| 4585429 | Apr., 1986 | Marier.
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| 4969856 | Nov., 1990 | Miyata et al.
| |
| 5254041 | Oct., 1993 | Duclo.
| |
| RE35617 | Sep., 1997 | Krivec.
| |
| 5720681 | Feb., 1998 | Benson.
| |
| 5967286 | Oct., 1999 | Hokanson et al.
| |
| 6120399 | Sep., 2000 | Okeson et al.
| |
| 6149540 | Nov., 2000 | Johnson et al.
| |
| 6155940 | Dec., 2000 | Templeton.
| |
| 6186915 | Feb., 2001 | Dietl.
| |
| 6248035 | Jun., 2001 | Bartlett.
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| 6336878 | Jan., 2002 | Ehrlich et al.
| |
| 6342024 | Jan., 2002 | Walter et al.
| |
| 6354419 | Mar., 2002 | Dalbiez et al.
| |
| 6502479 | Jan., 2003 | Lee.
| |
| 2001/0049312 | Dec., 2001 | Warner et al.
| |
| 2002/0019280 | Feb., 2002 | Brown.
| |
| 2002/0032088 | Mar., 2002 | Korenjak et al.
| |
| 2002/0065156 | May., 2002 | Younggren et al.
| |
| 2002/0119846 | Aug., 2002 | Kitai et al.
| |
| 2002/0155909 | Oct., 2002 | Roby.
| |
| 2002/0160867 | Oct., 2002 | Katou.
| |
| 2004/0229724 | Nov., 2004 | Kailes.
| |
| Foreign Patent Documents |
| 01093656 | Apr., 1989 | JP.
| |
Other References
Duane Watt, "Found, The Missing Half of the Secondary Clutch", SnowTech,
Sep. 1997, pp114-119.
Three images of driven pulley system (before Jan. 17, 2003).
|
Primary Examiner: Johnson; Vicky A.
Attorney, Agent or Firm: Barnes & Thornburg LLP
Claims
What is claimed is:
1. A driven pulley system for use in a torque converter, the driven pulley system comprising
movable first and second flanges arranged to squeeze a belt of the torque converter
between the first and second flanges and one of said flanges axially movable relative
to the other,
a spring fixedly coupled to the flanges, and
means for relatively axially moving the one of said flanges to adjust the squeeze
of the belt by the first and second flanges, the moving means including a worm
gear and a worm arranged to rotate the worm gear to wind or unwind the spring to
cause relative axial movement between the first and second flanges.
2. The driven pulley system of claim 1, wherein the spring includes relatively
movable first and second spring ends and the worm gear is coupled to the first
spring end to rotate the first spring end relative to the second spring end.
3. The driven pulley system of claim 1, wherein the worm gear includes teeth
formed in a radially outer portion of the worm gear and the worm is positioned
radially outwardly from the worm gear and includes threads that engage the teeth
to rotate the worm gear.
4. The driven pulley system of claim 1, further comprising a cam, a cam-follower
mount fixed to the first flange, and a cam follower that is mounted to the cam-follower
mount and arranged to follow the cam, wherein the moving means includes a support
frame, the worm and the worm gear are mounted to the support frame, and the support
frame is mounted to the cam-follower mount.
5. The driven pulley system of claim 4, wherein the second flange includes a
channel and at least one of the cam-follower mount and the support frame extends
into the channel.
6. The driven pulley system of claim 1, further comprising spring-centering means
for engaging an outer diameter portion of the spring to limit radial movement of
the spring to center the spring generally on a rotation axis about which the spring
rotates, and wherein the spring-centering means is mounted to the moving means.
7. A driven pulley system for use in a torque converter of a vehicle, the driven
pulley system comprising
a motion-transmitting fixed unit arranged to be fixed to a rotatable output shaft
of the vehicle for rotation therewith to transmit motion between the output shaft
and a belt included in the torque converter, the fixed unit including a fixed flange,
a belt-tensioning movable unit arranged for movement relative to the fixed unit,
the movable unit including a spring positioner and a movable flange arranged for
movement with the spring positioner, the fixed and movable flanges being arranged
to receive the belt therebetween to squeeze the belt, and
a spring including a fixed spring end arranged for movement with the fixed unit
and a movable spring end arranged for movement with the movable unit, the spring
positioner including a rotatable worm and a rotatable worm gear, the spring positioner
being arranged such that rotation of the worm rotates the worm gear to rotate the
movable spring end relative to the fixed spring end to cause axial movement of
the spring positioner to move the movable flange axially relative to the fixed
flange to adjust the squeeze of the belt by the fixed and movable flanges.
8. The driven pulley system of claim 7, wherein the worm is arranged to rotate
about a first axis and the worm gear is arranged to rotate about a second axis
different from the first axis when the worm is rotated about the first axis.
9. The driven pulley system of claim 7, wherein the worm gear includes teeth
formed in a radially outer portion of the worm gear and the worm is positioned
radially outwardly from the worm gear and includes threads that engage the teeth
to rotate the worm gear.
10. The driven pulley system of claim 7, wherein the spring positioner includes
a support frame and the worm and the worm gear are mounted to the support frame.
11. The driven pulley system of claim 10, wherein the support frame includes
a worm cavity and the worm is positioned in the worm cavity.
12. The driven pulley system of claim 11, wherein the worm cavity includes a
worm bearing surface and the spring is arranged to be loaded in torsion to cause
the worm gear to bias an end of the worm into engagement with the worm bearing surface.
13. The driven pulley system of claim 12, wherein the spring positioner includes
a worm retainer that is positioned in the cavity and arranged to engage the worm
to retain the worm in the worm cavity.
14. The driven pulley system of claim 11, wherein the worm gear is annular and
the support frame includes an annular gear-receiving channel that receives the
worm gear and is positioned radially inwardly from the worm cavity.
15. The driven pulley system of claim 10, wherein the worm gear is annular and
the support frame includes an annular gear-receiving channel receiving the worm gear.
16. The driven pulley system of claim 7, wherein the worm gear includes a spring
end receiver receiving the movable spring end.
17. A driven pulley system for use in a torque converter, the driven pulley system comprising
a fixed flange arranged to be fixed to a rotatable output shaft of the vehicle
for rotation therewith,
a movable flange arranged for movement relative to the fixed flange when the
fixed flange is fixed to the output shaft, the fixed and movable flanges being
arranged to receive therebetween a belt included in the torque converter,
a spring fixedly coupled to the flanges arranged to rotate about a rotation axis,
the spring including an outer diameter portion, the spring including a fixed spring
end arranged for movement with the fixed flange and a movable spring end arranged
for movement with the movable flange, the movable spring end movable about the
rotational axis with respect to the fixed spring end, and
a spring-centering device coupled to the movable flange for movement therewith
relative to the fixed flange and arranged to engage the outer diameter portion
to limit radial movement of the spring to center the spring generally on the rotation axis.
18. The driven pulley system of claim 17, wherein the spring-centering device
includes an axially extending centering rib arranged to engage the outer diameter portion.
19. The driven pulley system of claim 17, further comprising a spring positioner,
wherein the spring positioner is arranged to position the spring between the spring
positioner and the first flange, and the spring-centering device is included in
the spring positioner.
20. The driven pulley system of claim 19, wherein the spring positioner includes
a an axially extending leg and the spring-centering device includes an axially
extending centering rib is mounted to the leg.
21. The driven pulley system of claim 20, further comprising a cam, a cam-follower
mount fixed to the second flange, and a cam follower mounted to the cam-follower
mount and arranged to follow the cam, the leg is mounted to the cam-follower mount,
and the first flange includes a channel into which at least one of the cam-follower
mount and leg extends.
22. The driven pulley system of claim 20, wherein the spring positioner includes
an axially extending second leg, the spring-centering device includes another axially
extending centering rib mounted to the second leg and arranged to engage the outer
diameter portion, and the spring-centering ribs are parallel to one another.
Description
BACKGROUND
The present disclosure relates to torque converters and more particularly to
driven pulley systems for use in torque converters.
Torque converters are used on vehicles to promote vehicle engine performance.
A torque converter is continuously variable in response to both engine speed (i.e.,
engine rpm) and torque (i.e., rotational resistance) encountered by a rotatable
ground-engaging element (e.g., snowmobile track, wheel) of the vehicle.
A torque converter typically includes a belt trained about a driver pulley system
and a driven pulley system. The driver pulley system is adjustable in response
to engine speed. The driven pulley system is adjustable in response to torque.
Adjustment of the driver and driven pulley systems varies the "shift ratio" of
the torque converter to allow the engine to operate at a desired engine speed.
SUMMARY
According to the present disclosure, a driven pulley system is disclosed
for use in a torque converter of a vehicle. The driven pulley system comprises
a motion-transmitting fixed unit and a belt-tensioning movable unit. The fixed
unit is arranged to be fixed to a rotatable output shaft of the vehicle for rotation
with the output shaft to transmit motion between the output shaft and a belt included
in the torque converter. The movable unit is arranged for movement relative to
the fixed unit to tension the belt to promote engine speed responsiveness and torque
responsiveness of the torque converter.
The fixed unit includes a fixed flange and the movable unit includes a movable
flange. The fixed and movable flanges receive the belt therebetween and cooperate
to squeeze the belt.
The movable unit includes a spring positioner for use with a spring included
in the driven pulley system. The spring has a fixed spring end arranged for movement
with the fixed unit and a movable spring end arranged for movement with the movable
unit. The spring positioner includes a worm and a worm gear. Rotation of the worm
rotates the worm gear to rotate the movable spring end relative to the fixed spring
end to wind or unwind the spring somewhat. Such winding or unwinding of the spring
causes axial movement of the spring positioner which, in turn, moves the movable
flange axially away from or toward the fixed flange to adjust the squeeze of the
belt by the fixed and movable flanges. Belt squeeze adjustability is useful in
controlling maximum engine speed.
Additional features and advantages of the disclosure will become apparent
to those skilled in the art upon consideration of the following detailed description
exemplifying the best mode of the disclosure as presently perceived.
BRIEF DESCRIPTION OF THE DRAWINGS
The detailed description particularly refers to the accompanying figures in which:
FIG. 1 is a diagrammatic view showing components of a vehicle including a torque
converter that is continuously variable in response to vehicle engine speed and
torque experienced by a vehicle ground-engaging element and showing the torque
converter including a belt interconnecting a driver pulley system coupled to the
vehicle engine and a driven pulley system coupled to an output shaft which is connected
to the ground-engaging element via a gear box;
FIG. 2 is a perspective view of a snowmobile, with portions broken away, showing
the snowmobile including a torque converter having a belt trained about a driver
pulley system (on the left) and a driven pulley system (on the right);
FIG. 3 is an enlarged perspective view showing the driven pulley system and
a tool aligned for insertion into a cavity formed in support frame of a spring
positioner included in the driven pulley system to adjust the squeeze of a belt
between a fixed flange (located in front of the belt) and a movable flange (located
behind the belt);
FIG. 4 is an exploded perspective view showing most of the components of the
driven pulley system grouped into one of (1) a motion-transmitting fixed unit (at
bottom of page) to be fixed to the output shaft (at top left of page) of the snowmobile
for rotation therewith to transmit motion between the output shaft and the belt
and (2) a belt-tensioning movable unit (at top of page) to be mounted for movement
relative to the fixed unit to tension the belt during operation of the torque converter
and showing a spring to be mounted to the fixed and movable units;
FIG. 5 is a front elevation view of the driven pulley system of FIG. 3 showing
the tool inserted into the cavity for rotation about a tool axis in either a squeeze-increasing
direction (indicated by a thick arrow) or a squeeze-decreasing direction (indicated
by a thin arrow) to rotate a movable spring end that is included in the spring
and is visible through an arcuate window formed in the frame about a driven rotation
axis in either (1) a spring-unwinding, squeeze-increasing direction (indicated
by a thick arrow also) to unwind the spring somewhat to increase belt squeeze in
response to rotation of the tool in its squeeze-increasing direction or (2) a spring-winding,
squeeze-decreasing direction (indicated by a thin arrow also) to wind the spring
somewhat to decrease belt squeeze in response to rotation of the tool in its squeeze-decreasing direction;
FIG. 6 is an enlarged front elevation view of the tool and spring positioner
of FIG. 5, with portions broken away, showing the tool rotating a worm mounted
in the cavity formed in the support frame to rotate a worm gear to rotate the movable
spring end between exemplary positions shown in phantom;
FIG. 7 is a side elevation view of the driven pulley system of FIG. 5, with
portions broken away, showing the belt squeezed between the fixed flange (located
below the belt) and the movable flange (located above the belt) and showing that
the movable flange is arranged to move axially outwardly toward the fixed flange
in a squeeze-increasing direction (indicated by a thick arrow) to increase belt
squeeze in response to rotation of the tool and movable spring end in their squeeze-increasing
directions and to move axially inwardly away from the fixed flange in a squeeze-decreasing
direction (indicated by a thin arrow 0 to decrease belt squeeze in reponse
to rotation of the tool and movable spring end in their squeeze-decreasing directions;
FIG. 8 is a sectional view taken along lines 8-8 of FIG. 7 showing
the spring positioned between a pair of legs included in the support frame and
showing a spring-centering device in the form of a pair of spring-centering ribs
mounted on each leg for engagement with an outer diameter portion of the spring
to limit out-of-balance, radial movement of the spring due to centrifugal forces
on the spring to center the spring generally on the driven rotation axis;
FIG. 9 is an enlarged view of a detail of FIG. 8 now showing engagement between
the outer diameter portion of the spring and the two spring-centering ribs on one
of the frame legs to center the spring generally on the driven rotation axis;
FIG. 10 is an enlarged exploded perspective view showing the spring and the
spring positioner which includes, from left to right, the worm gear, the worm,
the support frame, a number of fasteners for mounting the support frame, and a
worm retainer;
FIG. 11 is an enlarged elevation view, with portions broken away, showing the
worm retainer positioned in front of the worm in the cavity to retain the worm therein;
FIG. 12 is a rear perspective view of the spring positioner showing the worm
gear located in an annular gear-receiving channel formed in the support frame and
showing one of the legs with a pair of axially extending spring-centering ribs
mounted thereto; and
FIG. 13 is a sectional view taken along lines 13-13 of FIG. 12.
DETAILED DESCRIPTION
A torque converter
10 for use in a vehicle
12 is shown in FIGS.
1
and 2. In the illustrated embodiment, the vehicle
12 is a snowmobile. It
is within the scope of this disclosure for the torque converter
10 to be
used with other types of vehicles such as utility vehicles, all-terrain vehicles,
motorcycles, mini-bikes, and go-karts, to name a few.
The torque converter
10 is continuously responsive to the speed of an
engine
14 of the vehicle
12 and to torque encountered by a ground-engaging
element
16 (e.g., snowmobile track as in illustrated embodiment, wheel)
of the vehicle
12. The torque converter
10 is arranged to "upshift"
to convert increased engine speed into an increased rotation rate of the element
16 and thus an increase in vehicle speed and is arranged to "downshift"
to convert decreased engine speed into a decreased rotation rate of the element
16 and thus a decrease in vehicle speed. If the element
16 encounters
increased torque (such as when going uphill), the torque converter
10 downshifts
to allow the engine to operate at a desired engine speed.
The torque converter
10 includes a driver pulley system
18, a driven
pulley system
20, and a belt
22 (e.g., a V-belt) trained about the
systems
18,
20, as shown in FIGS. 1 and 2. Driver pulley system
18
is coupled to a drive shaft of engine
14 for rotation therewith. An exemplary
driver pulley system which may be used as system
18 is disclosed in U.S.
Pat. No. 6,155,940, the disclosure of which is hereby expressly incorporated by
reference herein. Driven pulley system
20 is coupled to an output shaft
24 (e.g., jackshaft) for transmission of motion between the belt
22
and the output shaft
24. The output shaft
24 operates a gear box
26 for rotation of the ground-engaging element
16.
The driven pulley system
20 is arranged to squeeze the belt
22.
The driven pulley system
20 is adjustable to change the extent to which
it squeezes the belt
22. A tool
28 (e.g., hexagon wrench) shown in
FIG. 3 may be used to adjust belt squeeze as discussed in more detail herein.
Belt squeeze may be adjusted to control maximum engine speed. It may be desirable,
for example, for the engine
14 to operate in a higher performance mode,
such as for racing of the vehicle
12. To operate in a higher performance
mode, the engine
14 needs to be able to operate at a higher engine speed.
The driven pulley system
20 may be adjusted to increase the belt squeeze
to increase the maximum speed at which the engine
14 is allowed to operate.
On the other hand, it may be desirable for the engine
14 to operate in a
lower performance mode. In such a case, the driven pulley system
20 may
be adjusted to decrease the belt squeeze to decrease the maximum speed at which
the engine
14 is allowed to operate.
Belt squeeze may also be adjusted to account for wear on the belt. A newer belt
may require less belt squeeze than a worn belt. As a belt wears, it tends to "glaze"
or become more slick. A worn belt could slip on the driven pulley system
20
if belt squeeze were not adjusted. Thus, to avoid belt slippage by a worn belt,
belt squeeze may be increased.
The driven pulley system
20 includes a motion-transmitting fixed unit
30, a belt-tensioning movable unit
32, and a coil spring
34,
as shown in FIGS. 1 and 4. The fixed unit
30 is fixed to the output shaft
24 for rotation therewith about a driven rotation axis
35 and is
arranged to transmit motion between the belt
22 and the output shaft
24.
The movable unit
32 is arranged for axial movement and rotation relative
to the fixed unit
30 to tension the belt
22 to promote responsiveness
of the torque converter
10 and to promote operation of the engine
14
at a desired engine speed. The fixed unit
30 includes a fixed flange
36
and the movable unit
32 includes a movable flange
38 axially and
rotatably movable relative to the fixed flange
36. The flanges
36,
38 cooperate to squeeze the belt
22 therebetween.
The spring
34 provides the belt-squeezing force for the fixed and movable
flanges units
30,
32 to squeeze the belt
22. A spring positioner
40 shown in FIGS. 1,
3, and
4-
7 and included in the
movable unit
32 is arranged to adjust the spring
34 to adjust belt
squeeze by the flanges
36,
38 in response to operation of the tool
28, as discussed in more detail herein. The spring positioner
40
may be referred to as means for relatively axially moving the flanges
36,
38 to adjust the squeeze of the belt
22 thereby.
Components of the fixed unit
30 are shown in FIG. 4. The fixed
unit
30 includes a shaft-receiving sleeve
42, the annular fixed flange
36, and a pair of cams
46. The sleeve
42 is keyed to the output
shaft
24 so as to be fixed thereto for rotation therewith. The sleeve
42
extends into a central hole
47 formed in the fixed flange
36. The
fixed flange
36 is fixed to the sleeve
42 for rotation therewith.
Each cam
46 is arranged to be removably mounted to a fixed flange hub portion
44 by fasteners
45 to extend through a fixed flange channel
48
formed in the hub portion
44 into a movable flange channel
50 formed
in a movable flange hub portion
51 of the movable flange
38.
Components of the movable unit
32 are shown in FIG. 4. The movable
unit
32 includes the annular movable flange
38, the spring positioner
40, a cam follower
52 for each cam
46, and a cam-follower
mount
54 for each cam follower
52. The sleeve
42 extends through
a central hole
56 formed in the movable flange hub portion
51 such
that the movable flange
38 is journalled on the sleeve
42 for rotation
relative thereto. The cam-follower mounts
54 are fixed to the movable flange
hub portion
51. Each cam follower
52 is mounted to its cam-follower
mount
54 for engagement with a cam
46. The cam follower
52
is arranged to follow the cam
46 to cause the movable flange
38 to
rotate relative to the fixed flange
36 to tension the belt
22 upon
axial movement of the movable flange
38 away from the fixed flange
36
due to radially inward movement of the belt
22 between the flanges
36,
38. In the illustrated embodiment, each cam follower
52 is a roller
and the cam-follower mounts
54 are towers formed monolithically with the
movable flange hub portion
62.
The spring positioner
40 is mounted to the cam-follower mounts
66
for movement therewith, as shown in FIG. 7. The spring positioner
40 is
arranged to position the spring
34 between the spring positioner
40
and the fixed flange
36.
The spring positioner
40 includes a support frame
58 shown in FIGS.
3-13 and a worm system mounted to the support frame
58. The worm system
includes a worm
60 and an annular worm gear
62 and is used to wind
or unwind the spring
34 somewhat to cause the movable flange
38 to
move axially relative to the fixed flange
36 to adjust the squeeze of the
belt
22 by the flanges
36,
38, as described in more detail herein.
The support frame
58 includes a pair of legs
64, as shown in FIGS.
3-5 and
7-
13. Each leg
64 is mounted to a cam-follower mount
54 by a pair of fasteners
66. The legs
64 and cam-follower
mounts
54 access one another through the fixed flange channels
48.
The legs
64 and cam-follower mounts
54 are arranged for movement
in the fixed flange channels
48 as the movable unit
32 moves relative
to the fixed unit
30. The cam-follower mounts
54 are positioned in
the channels
48 when the flanges
36,
38 are closest to one
another due to the driven pulley system
20 being at rest or idling, as shown
in FIG. 7. As the driven pulley system
20 begins to operate and the flanges
36,
38 move axially away from one another due to radially inward
movement of the belt
22, the cam-follower mounts
54 withdraw from
the channels
48 and the legs
64 move into the channels
48.
The support frame includes an annular worm system support plate
68, as
shown, for example in FIGS. 3-13. The plate
68 is mounted to the legs
64.
A central hole
70 formed in the plate
68 is arranged to receive the
sleeve
42 and output shaft
24.
The worm
60 and worm gear
62 are mounted to the plate
68.
The plate
68 includes a worm cavity
72 and an annular gear-receiving
channel
74. The worm
60 is positioned in the worm cavity
72
for rotation therein. The worm gear
62 is positioned in the gear-receiving
channel
74 for rotation therein. The worm cavity
72 is positioned
radially outwardly from the gear-receiving channel
74. As such, the worm
60 is positioned radially outwardly from the worm gear
62. The plate
68 is formed to include a counterweight
75 to counterbalance the
worm
60.
The worm
60 engages the worm gear
62 for rotation thereof, as shown
in FIG. 6. The worm
60 includes threads
76 that engage teeth
78
formed in a radially outer portion
80 of the worm gear
62.
The spring
34 is mounted to the fixed flange
36 and the worm gear
62, as shown in FIG. 3. The spring
34 includes a fixed spring end
82 and a movable spring end
84. The fixed spring end
82 is
received by a fixed spring end receiver
86 included in the fixed flange
hub portion
44. In the illustrated embodiment, the fixed spring end receiver
86 is a hole formed in the hub portion
44. The movable spring end
84 is received by a movable spring end receiver
88 included in the
worm gear
62. The movable spring end receiver
88 is a hole formed
in the worm gear
62. The movable spring end
84 is arranged to be
visible through one of two arcuate windows
90 formed in the plate
68.
The spring
34 is preloaded in compression and torsion. The spring
34
is preloaded in compression to push the spring positioner
40 axially outwardly
away from the fixed flange
36 so as to bias the movable flange
38
toward the fixed flange
36 and to bias the belt
22 radially outwardly
on the flanges
36,
38. As such, the spring
34 push the worm
gear
62 axially outwardly against the plate
68 in the gear-receiving
channel
74. The spring
34 is preloaded in torsion in that it is normally
wound up somewhat. As such, the spring
34 biases the worm gear
62
against the worm
60 so as to bias an inner end
92 of the worm
60
against a worm bearing surface
94 that is shown in FIG. 6 and included in
the worm cavity
72. In this way, the worm
60 and the worm gear
62
are retained in place.
The spring positioner
40 includes a worm retainer
96 that is shown
in FIG. 6 and arranged to retain the worm
60 in the worm cavity
72
in the event that the spring
34 is unwound so as to completely lose its
torsion preload. The worm retainer
96 is positioned between an outer end
98 of the worm
60 and a tool access opening
100 into the worm
cavity
72 for engagement with the outer end
98 to block egress of
the worm
60 from the cavity
72 through the opening
100. In
the illustrated embodiment, the worm retainer
96 is a dowel pin press fit
into a retainer-receiving socket
102 formed in the plate
68.
The spring positioner
40 is used to adjust belt squeeze, as shown in FIGS.
5-7. The tool
28 is inserted through the tool access opening
100
into the worm cavity
72 and into engagement with the outer end
98
of the worm
60. The tool
28 is rotatable about a tool axis
104
in either a squeeze-increasing direction
106 or a squeeze-decreasing direction
108. Rotation of the tool
28 in the squeeze-increasing direction
106 rotates the worm
60 in the squeeze-increasing direction
106.
Rotation of the tool
28 in the squeeze-decreasing direction
108 rotates
the worm
60 in the squeeze-decreasing direction
108.
Rotation of the worm
60 rotates the worm gear
62 and the movable
spring end
84 coupled thereto, as shown in FIG. 6. Rotation of the worm
60 in the squeeze-increasing direction
106 rotates the worm gear
62 and the movable spring end
84 in a spring-unwinding, squeeze-increasing
direction
110 to rotate the movable spring end
84 relative to the
fixed spring end
82 to unwind the spring
34 somewhat. Rotation of
the worm
60 in the squeeze-increasing direction
108 rotates the worm
gear
62 and the movable spring end
84 in a spring-winding, squeeze-decreasing
direction
112 to rotate the movable spring end
84 relative to the
fixed spring end
82 to wind the spring
34 somewhat. The windows
90
allow a person using the tool
28 to see movement of the movable spring end
84.
Winding or unwinding the spring
34 causes the spring positioner
40
to move axially relative to the fixed flange
36. The spring positioner
40
moves axially outwardly away from the fixed flange
36 when the spring
34
is unwound in the spring-unwinding, squeeze-increasing direction
110. The
spring positioner
40 moves axially inwardly toward the fixed flange
36
when the spring
34 is wound in the spring-winding, squeeze-decreasing direction
112.
Axial movement of the spring positioner
40 relative to the fixed flange
36 moves the movable flange
38 axially relative to the fixed flange
36, as shown in FIG. 7. The movable flange
38 moves axially outwardly
toward the fixed flange
36 in a squeeze-increasing direction
114
to increase the squeeze of the belt
22 between the flanges
36,
38
when the spring positioner
40 moves axially outwardly. The movable flange
38 moves axially inwardly away from the fixed flange
36 in a squeeze-decreasing
direction
116 to decrease the squeeze of the belt
22 between the
flanges
36,
38 when the spring positioner
40 moves axially inwardly.
Belt squeeze adjustment affects radial movement of the belt
22 between
the flanges
36,
38. Increasing belt squeeze makes it more difficult
for the belt
22 to move radially inwardly on the driven pulley system
20
which, in turn, makes it more difficult for the belt
22 to move radially
outwardly on the driver pulley system
18. With respect to engine performance,
this allows the speed of the engine
14 to increase more readily to achieve
higher engine performance. Decreasing belt squeeze makes it easier for the belt
22 to move radially inwardly on the driven pulley system
20 which,
in turn, makes it easier for the belt
2 to move radially outwardly on the
driver pulley system
18. In this way, maximum engine speed can be restricted.
Use of the worm
60 and worm gear
62 allows precision belt squeeze
adjustment and thus precision adjustment of the maximum engine speed.
During operation of the torque converter
10, centrifugal forces on
the spring
34 may tend to cause out-of-balance, radial movement of the spring
34 off center from the driven rotation axis
35. The spring positioner
40 includes a spring-centering device
118 shown in FIGS. 8,
9,
12, and
13 and arranged to engage an outer diameter portion
120
of the spring
34 to limit such out-of-balance, radial movement of the spring
34 to center the spring
34 on the driven rotation axis
35.
The spring-centering device may also be referred to as spring-centering means.
The spring-centering device
118 includes at least one spring-centering
rib
122, as shown in FIGS. 8,
9,
12, and
13. In the
illustrated embodiment, there are two axially extending spring-centering ribs
122
mounted to a radially inner surface
124 of each leg
64. The spring-centering
ribs
122 are parallel to one another and are positioned radially outwardly
from the spring
34 for engagement with the outer diameter portion
120.
There is normally a small clearance between the ribs
122 and the outer
diameter portion
120, as shown in FIG. 8. When the engine
14 is at
rest or idling, the clearance is about 0.02 inch. The clearance may increase to
about 0.03 inch as engine speed increases and the spring
34 winds up.
There are times, however, when the spring
34 may shift radially due
to centrifugal forces on the spring
34, as shown in FIG. 9. The ribs
122
are arranged to engage the outer diameter portion
120 to limit such radial
movement of the spring
34 so that the spring
34 remains generally
centered on the driven rotation axis
35.
*
