U.S. patent number RE44,204 [Application Number 12/315,063] was granted by the patent office on 2013-05-07 for high torque retention joint in a tensioner.
This patent grant is currently assigned to Litens Automotive Partnership. The grantee listed for this patent is Harvey J. Dix, Jesse Dupuis. Invention is credited to Harvey J. Dix, Jesse Dupuis.
United States Patent |
RE44,204 |
Dix , et al. |
May 7, 2013 |
High torque retention joint in a tensioner
Abstract
A method of manufacturing a tensioner (10) by mounting an end
member (38) on an end of a hollow tensioner shaft (24) includes a
step of providing an end member (38) of sheet material with an
opening (76) having a plurality of annularly spaced inwardly
extending pointed projections (78). A hollow shaft (24) has an
outwardly extending shoulder (82) at an end portion thereof. A
relative axial movement between the end member (38) and the hollow
shaft (24) is effected so that the end member (38) abuts against
the shoulder (82) of the hollow shaft (24). The hollow shaft (24)
is deformed at the end portion radially outward to embed the
projections (78) into the hollow shaft (24) to thereby form a joint
(32) therebetween.
Inventors: |
Dix; Harvey J. (Thornton,
CA), Dupuis; Jesse (Hamilton, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Dix; Harvey J.
Dupuis; Jesse |
Thornton
Hamilton |
N/A
N/A |
CA
CA |
|
|
Assignee: |
Litens Automotive Partnership
(Woodbridge, CA)
|
Family
ID: |
22788907 |
Appl.
No.: |
12/315,063 |
Filed: |
June 13, 2001 |
PCT
Filed: |
June 13, 2001 |
PCT No.: |
PCT/CA01/00861 |
371(c)(1),(2),(4) Date: |
December 06, 2002 |
PCT
Pub. No.: |
WO01/96762 |
PCT
Pub. Date: |
December 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60211945 |
Jun 16, 2000 |
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Reissue of: |
10297694 |
Dec 6, 2002 |
7140992 |
Nov 28, 2006 |
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Current U.S.
Class: |
474/117 |
Current CPC
Class: |
F16D
1/072 (20130101); F16H 7/1218 (20130101); F16H
2007/0842 (20130101); F16H 2007/081 (20130101); F16H
7/0831 (20130101); F16H 2007/0893 (20130101) |
Current International
Class: |
F16H
7/08 (20060101) |
Field of
Search: |
;474/101,109,111,113,115,117 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 857 890 |
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Dec 1997 |
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EP |
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2.026.590 |
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Dec 1970 |
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FR |
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2 772 317 |
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Dec 1997 |
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FR |
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Other References
Patent Abstracts of Japan Publication No. 57025232 Publication
Date: Oct. 2, 1982 Title: Production of Plate Like Member Having
Hollow Shaft Part. cited by applicant.
|
Primary Examiner: Siconolfi; Robert A
Assistant Examiner: Momper; Anna
Attorney, Agent or Firm: Harness, Dickey & Pierce,
P.L.C.
Parent Case Text
RELATED APPLICATION
This application .Iadd.is a reissue of U.S. application Ser. No.
10/297,694, filed Dec. 6, 2002, now U.S. Pat. No. 7,140,992, which
.Iaddend.is a 371 filing of PCT Application CA01/00861, filed Jun.
13, 2001, which claimed priority to and all the benefits of U.S.
Provisional Application No. 60/211,945, filed on Jun. 16, 2000.
Claims
What is claimed is:
1. A tensioner comprising a fixed structure, a pivoting structure
mounted on said fixed structure for pivotal movement about a
pivotal axis, a pulley mounted on said pivoting structure for
rotational movement about a rotational axis parallel to said
pivotal axis, a spring operatively connected between said fixed
structure and said pivoting structure resiliently biasing the
pivoting structure in one direction, said fixed structure including
a hollow shaft and an end member formed of sheet metal of
predetermined thickness fixed to an end portion of said hollow
shaft, said hollow shaft receiving a bolt for fixedly attaching the
tensioner to a mounting structure, said end member engaging said
mounting structure for regulating a position of said tensioner
relative to said mounting structure, said end member including an
opening having a plurality of annularly spaced inwardly extending
pointed projections and a mounting knob positioned to engage within
an associated mating recess of said mounting structure, said end
portion of said hollow shaft having an outwardly extending shoulder
and a shaft end section adjacent said shoulder, said end portion
including a circumferential groove formed in said shaft end section
and positioned between said shoulder and said shaft end section,
said circumferential groove having a first diameter and said shaft
end section having a second diameter greater than said first
diameter, said end member abutting against said shoulder, said end
portion being deformed radially outwardly embedding the pointed
projections into said hollow shaft, said circumferential groove
providing a deformation path as said end portion of said hollow
shaft deforms radially outwardly.
2. A tensioner as claimed in claim 1 wherein said plurality of
pointed projections each has a rounded edge facing said
shoulder.
3. A tensioner as claimed in claim 2 wherein said hollow shaft is
deformed to occupy spaces between said plurality of pointed
projections.
4. A tensioner as claimed in claim 3 wherein said hollow shaft is
deformed to overlap said end member and clamp said end member
against said shoulder.
5. A tensioner as claimed in claim 1 wherein said end member is
hardened to be relatively harder than said hollow shaft.
6. A tensioner as claimed in claim 1 wherein said hollow shaft has
a hardness of between Rockwell B 65-85 and said end member has a
hardness of between Rockwell C 36-46.
.Iadd.7. A tensioner comprising a fixed structure, a pivoting
structure mounted on said fixed structure for pivotal movement
about a pivotal axis, a drive member mounted on said pivoting
structure for rotational movement about a rotational axis parallel
to said pivotal axis, a spring operatively connected between said
fixed structure and said pivoting structure resiliently biasing
said pivoting structure in one direction, said fixed structure
including a hollow shaft and an end member fixed to an end portion
of said hollow shaft, said hollow shaft including a longitudinally
extending aperture that is adapted for receiving a bolt for fixedly
attaching the tensioner to a mounting structure, said end member
engaging said mounting structure for regulating a position of said
tensioner relative to said mounting structure, said end member
including an opening, said end portion of said hollow shaft having
an outwardly extending shoulder and a shaft end section adjacent
said shoulder, said end member abutting against said shoulder, said
longitudinally extending aperture being deformed radially outwardly
such that said hollow shaft is received in a radially outward
direction into said opening, wherein said drive member is adapted
to support an endless power transmission element, and wherein said
longitudinally extending aperture includes a cylindrical portion
and a frustoconical portion that diverges outwardly from said
cylindrical portion, wherein said opening of said end member
includes a plurality of annularly spaced inwardly extending
projections, wherein said longitudinally extending aperture is
deformed radially outwardly such that said hollow shaft is received
in a radially outward direction into said inwardly extending
projections, wherein said end member includes a mounting knob that
is adapted to engage within an associated mating recess in said
mounting structure; and wherein said end portion of said hollow
shaft includes a circumferential groove formed in said shaft end
section and positioned between said shoulder and said shaft end
section, said circumferential groove having a first diameter and
said shaft end section having a second diameter greater than said
first diameter, said circumferential groove providing a deformation
path as said end portion of said hollow shaft deforms radially
outwardly..Iaddend.
Description
FIELD OF INVENTION
This invention relates to tensioners and more particularly to
tensioners having a high torque retention joint.
BACKGROUND OF THE INVENTION
Belt tensioners of the type herein contemplated are exemplary of
those used to tension the serpentine belt drive of a motor vehicle
engine. Other types of tensioners contemplated are those used for
timing belts. A tensioner of the type herein contemplated includes
a fixed structure, which is usually fixed to the engine housing and
a pivoting structure mounted on the fixed structure for pivotal
movement about a pivotal axis. A spring is operatively connected
between the fixed structure and the pivotal structure so as to
pivot the pivotal structure in one direction about the pivotal
structure. The pivoting structure carries a belt-engaging pulley
for rotational movement about a rotational axis parallel with the
pivotal axis. The pivotal movement of the pivoting structure
applies a constant tension to the belt and to compensate for
increases and decreases in the belt path length due to temperature
changes and wear.
The fixed structure comprises a hollow shaft and an end member. The
hollow shaft transmits the torque created by the spring to the end
member. The end member comprises tensioner stops or locating pins
that allow for the transmission of torque to the mounting
structure. A common form of locating pins is a pair of
diametrically opposed knobs protruding from the outward-facing
surface of the end member. Since the entire magnitude of torque
produced by the spring must be transmitted to the mounting
structure through the joint between the end member and hollow
shaft, a rigid joint is required between these members that is
capable of resisting torque.
A common method currently employed for the purpose of joining the
shaft and the end member is casting a positive torque retention
feature into the end of a cast aluminum shaft. This allows the two
elements to be joined, with material of the end portion of the
shaft deformed over the outer surface of the end member. This
practice creates a rigid joint capable of torque retention, but is
limited to a cast aluminum shaft design. Additional operations may
be added to create a torque retention feature on a steel shaft;
however production costs are increased.
There is a need for a cost-effective method of producing a joint
that is capable of high torque retention between a shaft and an end
member of a tensioner and for a more cost-effective tensioner
embodying such a joint.
SUMMARY OF THE INVENTION
It is an object of the present invention to fulfill the above need.
In accordance with the principles of the present invention, this
objective is achieved by providing a method of mounting a tensioner
end member on an end of a hollow tensioner shaft. This method
comprises the process of stamping, from a sheet of metal having a
predetermined thickness, an end member with a central opening
having an interior periphery formed with annularly spaced inwardly
extending pointed projections. A hollow shaft is formed having an
exterior axially outwardly facing shoulder in one end portion
spaced a distance from an associate end greater than the
predetermined sheet metal thickness. A relative axial movement
between the end member and hollow shaft is effected sufficient to
engage the end member against the shoulder of the hollow shaft.
Finally, the one end portion is deformed radially outwardly and a
section of the one end portion, extending beyond the end member, is
deformed axially inwardly into abutting engagement with an
outwardly facing surface of the end member adjacent the central
opening. The sharpness of the projections causes the metal of the
hollow shaft end portion to deform within the spaces between said
projections in such a way that the metal of the projections becomes
embedded within the metal of the hollow shaft, thereby resisting
relative movement between the hollow shaft and the end member.
The tensioner embodying the principles of the present invention
made from the method comprises a fixed structure for fixedly
attaching the tensioner to a mounting structure. A pivoting
structure is mounted on the fixed structure capable of pivotal
movements in opposite directions about a pivotal axis. A pulley is
mounted on the pivoting structure for rotational movement about an
axis parallel to said pivotal axis. A spring is operatively
connected between said fixed structure and said pivoting structure
to resiliently urge the pivoting structure in a belt engaging
direction. The fixed structure includes a metal hollow shaft having
an axis coincident with the pivotal axis and an end member formed
of sheet metal of predetermined thickness constructed and arranged
to be mounted to one end of the hollow shaft. The end member
includes a central opening having a periphery formed with annularly
spaced inwardly extending projections. The hollow shaft has an
exterior axially outwardly facing shoulder formed on the one end at
a distance greater than the predetermined thickness of the end
member. The end member is mounted on the hollow shaft in abutting
engagement with the shoulder. The hollow shaft one end portion is
deformed radially outwardly and a section of the one end portion
extends beyond the end member. This section is then deformed
axially inwardly into abutting engagement with an outwardly facing
surface of the end member adjacent the central opening. The metal
of the sharp projections cause the metal of the end portion of the
hollow shaft to deform within the spaces between the projections.
The metal of the projections then becomes embedded within the metal
of the hollow shaft to thereby resist relative movement between the
hollow shaft and the end member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a tensioner embodying the
principles of the present invention showing the same in tensioning
relation to a belt in an extended second position thereof in solid
lines and in a first position in dotted lines.
FIG. 2 is a cross-sectional view of the tensioner taken along line
2-2 of FIG. 1.
FIG. 3 is an enlarged top plan view of the end member of the
present invention as it is punched from sheet metal stock.
FIG. 4 is an enlarged cross-sectional view of the end member taken
along the lines 5-5 of FIG. 3.
FIG. 5 is an enlarged axial cross-sectional view of the one end
portion of the hollow shaft as it is made initially.
FIG. 6 is an enlarged cross-sectional view of the one end portion
of the hollow shaft as it is made initially with the end member
seated in abutting engagement with the exterior axially outwardly
facing shoulder of the hollow shaft prior to deformation.
FIG. 7 is an axial cross-sectional view of the one end portion of
the shaft and its connection with the end member taken showing a
punch which has completed the connection in a withdrawn
position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
INVENTION
Referring now more particularly to the drawings, there is shown
therein a tensioner, generally indicated at 10, which embodies the
principles of the present invention. The tensioner 10 is operable
to be mounted on a mounting structure such as an automotive vehicle
engine housing, a portion of which is generally illustrated in
FIGS. 1 and 2 at 14.
The tensioner 10 comprises, in general, a fixed structure,
generally indicated at 16, and a pivotal structure, generally
indicated at 18, pivotally mounted on the fixed structure 16 for
pivotal movements with respect thereto about a pivotal axis central
to said fixed structure. A pulley, generally indicated at 20 in
FIGS. 1 and 2, is rotatably mounted on the pivotal structure 18 for
rotational movement about a rotational axis parallel with the
pivotal axis. A spring in the form of a torsion coil spring 22 is
mounted between the fixed structure 16 and the pivotal structure 18
for resiliently urging the pivotal structure 18 in one direction,
which corresponds to a movement of the pulley 20 in a belt
tensioning relation.
The fixed structure 16 includes a hollow metal shaft 24 having a
throughbore 26 extending axially therethrough. As shown in FIG. 2,
the throughbore 26 receives a mounting bolt 28 that serves to
fixedly attach the fixed structure 16 to the mounting structure
14.
The present invention is particularly concerned with a high torque
retention joint generally indicated at 32, between one axial end of
the hollow shaft 24 and an end member 38 forming a part of the
fixed structure 16. The joint 32 is further described
hereinafter.
As shown in detail in FIG. 3, the end member 38 includes a pair of
mounting knobs 40 protruding axially outwardly from an outer
surface of the metal end member 38. The mounting knobs 40 are
configured and positioned to engage within a pair of mating
recesses 42 within the mounting structure 14. The mounting bolt 28
extends through the throughbore 26 of the hollow shaft 24 and is
threadedly engaged within the mounting structure 14. The bolt 28
thus mounted maintains the knobs 40 within the recesses 42 to
maintain a constant position relative to mounting structure 14. The
torsion spring 22 resiliently biases the pulley 20 toward a
position into tensioning relation to the belt 36. Shown in FIG. 2
is a pair of mounting knobs 40 and associated mating recesses 42
arranged in a diametrically opposed configuration. However, it is
also contemplated that the present invention may employ only a
singular mounting knob and mating recess, or an associated
plurality of both, having any configuration necessary to maintain a
constant position of the tensioner 10 relative to the mounting
structure 14.
The tensioner 10, as shown, is preferably a proportionally dampened
tensioner of the type disclosed in U.S. Pat. No. 4,473,362. As
shown, the pivotal structure 18 includes a hub portion 44, which is
journaled on the hollow metal shaft 24, by a suitable bearing
sleeve 46. A flanged damping sleeve 48 is mounted on the exterior
periphery of the arm hub portion 44 with its flange in engagement
with the inner surface of the fixed structure 16 axially opposite
the end member 38. A force-transmitting ring 50 is mounted in
surrounding relation to the damping sleeve 48 adjacent its flange
and in radial abutment with an adjacent volute of the torsion
spring 22. As the spring 22 expands and contracts during the
operational movements of the pivotal structure 18, a proportional
force is transmitted from the spring 22 to damping sleeve 48
through the ring 50. The proportional spring force is reflected in
a proportional sliding frictional damping force that controls the
movements of the pivotal structure 18 with respect to the fixed
structure 16.
The pivotal structure 18 also includes an arm structure 52 that is
integral with one end of the hub portion 44 and extends radially
outwardly therefrom. The circular-shaped inner section of the arm
portion 52 is formed with an axially inwardly projecting annular
flange portion 54 having a free end which cooperates with the free
end of an axially inwardly extending annular flange portion 56
formed integrally on the outer periphery of the inner surface of
the fixed structure 16 axially opposite the end member 38. The
flange portions 54 and 56 serve to substantially enclose the spring
22.
The pivotal structure 18 includes an integral shaft portion 60,
which extends axially inwardly from the outer end of the arm
structure 52. The exterior periphery of the shaft portion 60 has
the inner race of a ball bearing assembly 62 fixed thereon as by a
washer 64 and a headed bolt 66 suitably threadedly engaged within
the shaft portion 60. The head of the bolt 66 serves as a
tool-receiving element that aids in installation of the tensioner
10.
The pulley 20 is shown as being made of sheet metal so as to
provide an outer annular wall 68 having a smooth belt engaging
peripheral surface. It will be understood that the pulley wall 68
could be configured to present a poly groove-engaging surface of
the like. As shown, the pulley 20 includes a circular wall 70
extending radially and axially inwardly from one end of the outer
annular wall 68 which terminates in an integral hub portion 72
engaged with the outer race of the ball bearing assembly 62. The
pivotal structure 18 also includes an integral cup shaped portion
74 that generally surrounds the inner end of the ball bearing.
The Method and Resulting Joint
The high torque retention joint 32 embodying the principles of the
present invention is between the end member 38 and the hollow metal
shaft 24.
The end member 38 is preferably formed from a sheet of carbon steel
metal having a predetermined thickness as for example 3.17
millimeters. The end member 38 is formed in a conventional fashion,
preferably in a stamping process from the sheet metal stock. The
stamping process forms the end member to include a circular
exterior periphery and a central opening 76 having an interior
periphery formed with annularly spaced inwardly extending pointed
projections 78. It will be understood that while the preferred
embodiment of the projections 78 is as shown in FIG. 3, the number,
size, and geometry of the projections are variable through the
design of the punch. The stamping process forms the leading edge of
the central opening 76 with a rounded edge 80, as shown in FIG. 4,
whereas the opposite edge does not include such a round.
The hollow metal shaft 24 is made by conventional means, preferably
a turning process. One end portion, generally shown at 81, of the
hollow shaft 24 is shown in detail in FIG. 5. The hollow shaft 24
is formed with a throughbore 26 and an exterior axially outwardly
facing shoulder 82 disposed at a distance from a shaft edge 83
greater than the predetermined thickness of the end member 38. A
shaft end section 85 extends between the shaft edge 83 and the
shoulder 82. A radially inwardly extending circumferential groove
84 is formed in the shaft end section 85 and is positioned between
the shaft end section 85 and the shoulder 82. The circumferential
groove 84 has a first diameter and the shaft end section 85 has a
second diameter. The second diameter is greater than the first
diameter.
In forming the joint 32, an axial movement is effected between the
end member 38 and the hollow shaft 24 wherein the fillet edge 80 is
used as a lead-in for placement of the end member 38 upon the end
portion 81 of the hollow shaft 24 and with the adjacent surface of
the end member 38 facing axially inwardly until the latter is moved
into abutting engagement to shoulder 82, shown in detail in FIG. 6.
The configuration of the projections 78 and the configuration of
the periphery of the end portion 81 of the shaft 24 outwardly of
the shoulder 82 allows for the end member 38 to be mounted on the
end portion 81 of the shaft 24 without interference.
Once the initial mounting has been effected, the assembly is
mounted in a punch press wherein a punch 86, preferably tapered in
a frusto-conical configuration, is forcibly pressed axially
inwardly of the hollow shaft 24 through bore 26 effecting a
radially outwardly axially tapered deformation of the metal of the
end portion .Iadd.81 .Iaddend.of the hollow shaft 24. FIG. 7 shows
the arrangement of the end member 38 and the .[.one.]. end portion
.Iadd.81 .Iaddend.of the hollow shaft 24 following deformation.
.Iadd.Following deformation, the through bore 26 includes a
cylindrical portion 92 and a frusto-conical portion 94 that
diverges outwardly from the cylindrical portion 92. The
frusto-conical portion 94 has a length 96 that is greater than a
length 98 of the shaft end section 85. .Iaddend.The circumferential
groove 84 aids the deformation as the punch 86 travels axially
inwardly of the hollow shaft 24 through bore 26 and provides a
deformation path as the end portion .Iadd.81 .Iaddend.of the hollow
shaft 24 deforms radially outwardly. The metal of the sharp
projections 78 causes the metal of the .[.one.]. end portion
.Iadd.81 .Iaddend.of the hollow shaft 24 to be deformed within the
spaces between the projections 78, thus embedding the metal of the
projections 78 within the metal of the hollow shaft 24. The
arrangement of the fillet edge 80 adjacent shoulder 82 and the
taper of the punch 86 allows the radially longer opposite edge
portion of the projections 78 to receive the deformed metal of the
hollow shaft 24.
The punch 86, also shown in FIG. 7, includes an exterior axially
outwardly facing annular shoulder 88 positioned to engage and
deform a corresponding annular portion of the metal of the hollow
shaft during the final extent of movement of the punch 86. The
shoulder 88 deforms a corresponding annular portion of the one end
portion of the hollow shaft 24 radially outwardly beyond the
outwardly facing surface of the end member 38 into abutting
engagement therewith forming an overlap 90. Overlay 90 cooperates
with shoulder 82 to clamp the end member 38. In addition, the
shoulder 88 deforms some of the metal of the hollow shaft 24
axially inwardly increasing the amount of metal of said hollow
shaft 24 within the spaces between the projections 78. This
increases the torque retention capability of the joint 32.
Furthermore, the overlap 90 provides the necessary axial force
retention required by many tensioner applications.
The resulting joint between the end member 38 and the hollow shaft
24 possesses a much greater torque retention capability than the
prior art, since the metal of the hollow shaft between the
projections must shear off in order for the joint to fail.
Furthermore, the present invention is more cost effective due to
the elimination of an additional manufacturing process and the use
of conventional production processes.
In the preferred embodiment, if the sharp projections 78 can be
manufactured with a relatively high degree of sharpness, the end
member 38 and hollow shaft 24 can have the same degree of hardness.
However, due to manufacturing difficulties encountered in ensuring
sharp edges on the tips of the sharp projections 78, a greater
difference in relative hardness is preferred. By way of example,
the shaft 24 is made from a relatively softer material such as SAE
J403, 12L14 steel (machined bar stock), having a hardness: Rockwell
B 65-85. The end member 38 is made from a relatively harder
material such as SAE J404 4130 steel (stamped sheet), having a
hardness: Rockwell C 36-46. The hardness can be achieved by furnace
heat treat after stamping.
While the present invention has been described in relation to the
above exemplary embodiments it will be understood that various
modifications may be made within the spirit and scope of the
invention. While the objects of the present invention have been
fully and effectively accomplished, it will be realized, however,
that the foregoing exemplary embodiments have been functional and
structural principles of this invention and are subject to change
without departure from such principles. Therefore, this invention
includes all modifications encompassed within the scope of the
following claims.
* * * * *