U.S. patent application number 10/191818 was filed with the patent office on 2003-02-06 for telescoping joint assembly and a method for making the same.
Invention is credited to Johnston, Alan, Mastrofrancesco, Luigi.
Application Number | 20030026644 10/191818 |
Document ID | / |
Family ID | 23759902 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030026644 |
Kind Code |
A1 |
Mastrofrancesco, Luigi ; et
al. |
February 6, 2003 |
Telescoping joint assembly and a method for making the same
Abstract
A telescoping joint assembly and a method for making a telescope
joint assembly 10. The joint assembly 10 has a pair of members 12,
14 which are telescopically engaged. Assembly 10 further includes a
resinous, plastic and/or polymer material 16 which shrinkably coats
or lines the inner shaft 12 after the inner shaft 12 is heated and
exposed to a substantially inert gas, thereby providing a
relatively durable and substantially "low friction" bearing or
surface 18 which is effective to promote and/or assist the
telescopic sliding motion between the members 12, 14.
Inventors: |
Mastrofrancesco, Luigi;
(Northville, MI) ; Johnston, Alan; (Rochester
Hills, MI) |
Correspondence
Address: |
Chupa & Alberti, P.C.
Suite 205
31313 Northwestern Highway
Farmington Hills
MI
48334
US
|
Family ID: |
23759902 |
Appl. No.: |
10/191818 |
Filed: |
July 9, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10191818 |
Jul 9, 2002 |
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09443222 |
Nov 18, 1999 |
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6473968 |
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Current U.S.
Class: |
403/109.1 |
Current CPC
Class: |
F16C 29/02 20130101;
B62D 1/185 20130101; Y10T 29/53096 20150115; Y10T 29/49622
20150115; Y10T 29/49885 20150115; Y10T 403/32467 20150115; F16C
2326/24 20130101; Y10T 29/49641 20150115 |
Class at
Publication: |
403/109.1 |
International
Class: |
B21K 001/10 |
Claims
What is claimed is:
1) A telescoping joint assembly comprising: a first member having
an inner cavity; a second member which is selectively and movably
disposed within the cavity and which cooperates with the first
member to form a gap; and a certain amount of thermoplastic
material which is disposed within the gap and which selectively
shrinks and solidifies, thereby bonding to the second member and
allowing the second member to be slidably disposed within the
cavity.
2) The telescoping joint assembly of claim 1 wherein said cavity
has an oblong shape.
3) The telescoping joint assembly of claim 1 wherein said formation
comprises a knurled portion.
4) The telescoping joint assembly of claim 1 wherein said formation
comprises an indentation.
5) The telescoping joint assembly of claim 1 wherein said material
comprises a polymeric material.
6) The telescoping joint assembly of claim 5 wherein said polymeric
material comprises 6:6 nylon, acetal, thermoplastic.
7) A telescoping joint comprising: a first member having an inner
cavity with a concave surface; a second member having a convex
surface which is disposed within said cavity and which is separated
from said concave surface by a substantially uniform gap; and an
amount of a thermoplastic material disposed within said gap, said
material solidifying in response to a decrease in temperature, said
solidification of said material effective to bond said material to
said convex surface and to shrink said material by a predetermined
amount, thereby allowing said second member to be slidably movable
within said cavity.
8) The telescoping joint assembly of claim 7 wherein said convex
surface includes a protuberance effective to further bond said
material to said convex surface.
9) The telescoping joint assembly of claim 7 wherein said convex
surface includes an indentation effective to further bond said
material to said convex surface.
10) The telescoping joint assembly of claim 7 wherein said
thermoplastic material comprises 6:6 nylon, acetal
thermoplastic.
11) The telescoping joint assembly of claim 7 wherein said first
member and said second member concave surface are each oblong in
shape.
12) A method for manufacturing a telescoping joint assembly, said
method comprising the steps of: providing a first member having a
cavity of a first shape; providing a second member; heating said
first member; placing an amount of liquefied thermosetting material
within said cavity; heating said second member; inserting said
heated second member within said cavity effective to cause said
liquefied thermosetting material to be distributed within said
cavity and around said second member; and cooling said first member
effective to solidify said material and to shrink said material,
thereby bonding said material onto said second member.
13) The method of claim 12 further comprising the step of disposing
a knurl upon said second member, said knurl being effective to
secure said solidified material upon said second member.
14) The method of claim 12 further comprising the step of creating
an indentation within said second member, said indentation being
effective to secure said solidified material upon said second
member.
15) The method of claim 12 further comprising the step of placing
said first member, said second member, and said material within an
environment containing inert gas.
16) The method of claim 12 further comprising the step of applying
a lubricant to said solidified material.
17) The method of claim 12 further comprising the step of filling
said cavity with an inert gas.
18) The method of claim 12 wherein said inert gas comprises argon.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a joint assembly and a method for
making a joint assembly, and more particularly to a telescoping
joint assembly and a method for making a telescoping joint assembly
having a pair of members which telescopingly cooperate to form a
relatively tight and reliable joint.
BACKGROUND OF THE INVENTION
[0002] Automotive vehicles and other types of assemblies often
utilize telescoping type joints and/or joint assemblies to
operatively couple selectively rotatable shafts or members in a
manner which allows torque or rotational energy to be communicated
and/or transmitted by and between the coupled members, while
concomitantly allowing the coupled members to independently move
axially with respect to each other (e.g., to selectively move
"toward and away" from each other).
[0003] For example and without limitation, a vehicle steering
system or assembly generally includes a steering shaft or column
and a telescoping intermediate shaft which is coupled to and
transfers torque between a steering column and a steering gear
assembly. Particularly, the rotational energy of the steering
column is transferred through the telescoping intermediate shaft to
the gear assembly and the wheel suspension assembly, thereby
allowing the vehicle to be selectively steered.
[0004] Typically, the intermediate shaft comprises and/or includes
an inner shaft or member and an outer shaft or member which movably
and selectively receives and/or "mates" with the inner shaft or
member and which cooperates with the inner member to allow the
steering column and gear shaft to be "axially compliant" (i.e., to
selectively and independently move "toward and away" from each
other).
[0005] In order to substantially reduce friction and improve the
performance, compliance, and efficiency of this intermediate shaft
and/or steering shaft assembly (as well as other types of joint
assemblies), the inner member is typically coated or lined with a
resin, rubber or polymer material, or contains a bearing assembly.
The telescoping intermediate shaft compensates for the relative
movement between the vehicle body and vehicle frame which occurs as
the car is driven and allows at least one of the coupled members,
such as the steering column, to substantially and desirably
"collapse" in the event of a collision or accident, thereby
substantially reducing the probability of injury to the driver. The
telescoping shaft may further allow the steering column to be
adjusted by the driver in an axial or telescopic manner.
[0006] Although this intermediate shaft, as well as other
substantially similar types of prior joint assemblies, effectively
transmit torque between a pair of coupled members or shafts while
concomitantly allowing the coupled members to be axially compliant,
they suffer from some drawbacks.
[0007] For example and without limitation, these prior joint
assemblies are typically relatively loose fitting and do not have a
relatively precise fit or "correspondence" between the telescoping
members and/or between one or more of the telescoping members and
the liner or bearing assembly. Particularly, because the members
and the liner/bearing assembly are each formed by separate and
independent processes, the manufacturing "tolerance" associated
with each of the members and the liner/bearing assembly are
additively accumulated or "stacked", thereby resulting in a
relatively "loose" overall tolerance and a relatively imprecise or
relatively loose fit. As a result, these prior telescoping joint
assemblies suffer from undesirable "slop", "lash", vibration,
frictional loss, and/or "frictional lock-up", which require
relatively costly and complicated modifications.
[0008] Particularly, these undesirable attributes hinder and/or
undesirably diminish the sliding engagement between the telescoping
members, resulting in an inefficient transmission of torque or
rotational energy while concomitantly creating excessive wear and
fatigue to and of the telescoping members, thereby causing failure
and/or diminished performance (e.g., undesirably allowing
vibrational forces and/or other movements/forces to be readily
transferred between the coupled components and/or members, such as
between the wheel suspension assembly and the steering column).
[0009] Efforts to improve these relatively loose joints typically
include but are not limited to relatively costly sizing, adjusting,
or machining of the respective shafts. Furthermore, in order to
obtain a more precise tolerance or fit between the inner and outer
members, the members must typically undergo relatively complex and
undesirable machining processes after they have been formed and/or
after a lining has been applied to the inner and/or outer member.
This "post-fabrication" machining undesirably increases the
expense, time, and difficulty of the manufacturing process.
[0010] There is therefore a need to provide a telescoping joint
assembly for coupling two members or shafts which overcomes at
least some of the various and previously delineated drawbacks of
prior coupling assemblies; which allows torque and rotational
energy to be relatively efficiently transmitted between the two
coupled members or shafts, while concomitantly allowing each of the
members or shafts to be axially compliant; which provides for a
substantially "tight" fit between the telescoping members; which
substantially eliminates and/or reduces "slop", lash, frictional
loss, and/or "frictional lock-up"; and which substantially
eliminates the need for post-fabrication "machining" of the
telescoping members.
SUMMARY OF THE INVENTION
[0011] It is a first object of the invention to provide a
telescoping joint assembly and a method for making a telescoping
joint assembly which overcomes some or all of the previously
delineated drawbacks of prior telescoping joint assemblies.
[0012] It is a second object of the invention to provide a
telescoping joint assembly which selectively allows torque and/or
rotational energy to be transmitted and/or communicated between two
telescoping members, while concomitantly allowing the telescoping
members to selectively, independently, and reciprocally move toward
and away from each other.
[0013] It is a third object of the present invention to provide a
telescoping joint assembly which provides for substantially "tight"
or precise dimensional fit or correspondence between two
operatively assembled telescoping members.
[0014] It is a fourth object of the present invention to provide a
telescoping joint assembly which substantially eliminates and/or
reduces "slop", "lash", frictional losses and/or "frictional
lock-up", and which substantially eliminates and/or reduces the
amount of vibrational forces transferred between the coupled
members.
[0015] According to a first aspect of the present invention, a
telescoping joint assembly is provided. The telescoping joint
assembly includes a first member having an inner cavity; a second
member which is selectively and movably disposed within the cavity
and which cooperates with the first member to form a gap; a certain
amount of a thermoplastic material which is disposed within the gap
and which selectively shrinks and solidifies, thereby bonding to
the second member and allowing the second member to be slidably
disposed within the cavity.
[0016] According to a second aspect of the present invention a
method for making a telescoping joint assembly is provided. The
method includes the steps of providing a first member having a
cavity of a first shape; providing a second member adapted to be
inserted within the cavity; placing an amount of thermoplastic
material within the cavity; heating the cavity effective to liquefy
the thermoplastic material; heating the second member; inserting
the heated second member within the cavity, effective to cause the
thermoplastic material to be distributed within the cavity and
around the second member; cooling the first member effective to
solidify the material, thereby bonding the material onto the second
member and creating a telescoping joint assembly.
[0017] These and other objects, aspects, features, and advantages
of the present invention will become apparent from a consideration
of the following specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective unassembled view of a joint assembly
which is made in accordance with the teachings of the preferred
embodiment of the invention;
[0019] FIG. 2 is a cross sectional view of the joint assembly which
is shown in FIG. 1 and which is taken along view line 2-2;
[0020] FIG. 3 is an enlarged cross sectional view of the joint
assembly which is shown in FIG. 1, which is taken along the view
line 2-2, and which is shown in a partially fabricated state;
[0021] FIG. 4 is an enlarged cross sectional view of the joint
assembly which is shown in FIG. 1, which is taken along the view
line 2-2, and which is shown in a fabricated state;
[0022] FIG. 5 is a partial cross sectional view of the joint
assembly which is shown in FIG. 1, which is taken along the view
line 2-2, and which is shown in a fabricated and unassembled state;
and
[0023] FIG. 6 is an enlarged cross sectional view of the joint
assembly which is shown in FIG. 4, which is taken along view line
6-6, and which is shown in an assembled state.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
INVENTION
[0024] Referring now to FIGS. 1-6, there is shown a telescoping
joint assembly 10, which is made in accordance with the teachings
of the preferred embodiment of the invention. The joint assembly 10
includes an inner shaft or member 12 which is adapted to be
selectively, operatively and slidably inserted into and to
selectively engage a generally hollow or tubular outer shaft or
member 14. Assembly 10 further includes a resinous, plastic or
polymer material 16 which is inserted into member 14 and which, as
explained more fully below, coats or lines the inner shaft 12,
thereby providing a relatively durable and low friction bearing or
surface 18 which is effective to promote and/or assist the
telescopic sliding motion between the members 12, 14 in manner
which is more fully delineated below.
[0025] In the preferred embodiment of the invention, member 12
includes an outer surface 20, which is coated, lined or covered by
material 16, as best shown in FIGS. 4-6. Particularly, as best
shown in FIG. 6, surface 20 has a generally oblong cross sectional
shape which is cooperatively formed by two opposing substantially
flat surface portions 22, 24 which are integrally formed with and
which terminate upon opposed generally convex and semi-circular
surface portions 26, 28. Surface 20 includes a knurled or raised
projection, protuberance, or formation 30 which protrudes and/or
outwardly projects from surface 20 and which, as described more
fully and completely below, is adapted to selectively engage the
solidified material 16, thereby securing the material to member 12.
In other alternate embodiments, projection 30 comprises one or more
indentations, grooves or openings disposed upon and/or within
surface 20 and which are each effective to "hold" or secure at
least a portion of the solidified material 16 onto surface 20,
thereby securing at least a portion of the solidified material 16
to member 12.
[0026] Member 14 further includes and/or forms a cavity 34 which is
bounded by and/or is defined by an inner surface 32. Cavity 34 has
a generally oblong cross sectional shape which is substantially and
integrally formed by two opposing substantially flat surface
portions 36, 38 which are integrally formed with and which
terminate upon two opposed, concave, and semi-circular surface
portions 40, 42. As shown, surface 20 and surface 32 have
substantially similar and corresponding shapes with the exception
that surface 32 is relatively larger in size and/or surface area
than surface 20. Hence, when inner member 12 is inserted into
cavity 34, a substantially uniform distance or gap 44 is formed
between surface 20 and surface 32. In one non-limiting embodiment,
the distance or gap 44 between surfaces 20 and 32 (i.e., between
each of surfaces 22-28 and the respective and opposing surfaces
36-42) is substantially uniform. In alternate embodiments, surfaces
20 and 32 each include a plurality of conventional and
corresponding "splines" which are circumferentially formed upon the
respective surfaces 20, 32 and which are adapted to selectively and
cooperatively intermesh.
[0027] As best shown in FIGS. 4 through 6, material 16
substantially and uniformly coats or lines the portion of member 12
which telescopically penetrates cavity 34 and/or engages member 14.
Material 16 is resinous and/or polymeric in nature and, in one
non-limiting embodiment of the invention, comprises thermoplastic
material such as acetal, 6:6 nylon material. As discussed more
fully and completely below, once assembly 10 is fully assembled
and/or formed, material 16 substantially and uniformly occupies or
resides within gap 44. The outer surface 18 of the solidified
material 16 is substantially similar in shape to surfaces 20 and 32
with the exception that surface 18 is relatively larger in size
and/or has a relatively larger surface area than does surface 20
and is relatively smaller in size and/or has a relatively smaller
surface area than does surface 32. Hence, a substantially uniform
distance or gap 48 is formed between surfaces 18 and 32. The gap 48
between surfaces 18 and 32 is relatively small, thereby providing a
considerably precise fit between the engaging portions of members
12 and 14. In one non-limiting embodiment, the distance or gap 48
between surfaces 18 and 32 is substantially uniform and equal to
about 0.03 inches. This relatively minute gap 48 substantially
prevents members 12 and 14 from independently rotating with respect
to each other, thereby allowing joint assembly 10 to effectively
transmit torque between the selectively coupled members 12 and 14.
This relatively small distance 48 and precise "dimensional fit"
between material 16 and outer member 14 further substantially
eliminates "lash" and vibration and improves the overall
operational "smoothness" of assembly 10.
[0028] This relatively minute gap or distance 48 is created through
the novel method of assembling and/or fabricating joint assembly
10. As best shown in FIGS. 1-5, assembly 10 is assembled and/or
fabricated as follows.
[0029] Member 14 is initially inserted into a fixture 56, which
secures member 14 in a substantially "upright" position. Cavity 34
is then filled or "flooded" with an inert gas (e.g., the air and/or
other gasses resident within cavity 34 are forcibly and
intentionally replaced with an inert gas). In another non-limiting
embodiment, member 12 and 14 may also be immersed within the inert
gas or the gas filled cavity 34. In the preferred embodiment of the
invention the inert gas comprises argon gas, although other inert
gasses may be utilized. The presence of the inert gas within cavity
34 substantially prevents the metal of members 12, 14 from
oxidizing, and further substantially prevents degradation of
material 16. In other alternate embodiments, the entire assembly
and/or fabrication process is performed within an inert gas
environment, thereby causing substantially the entire surface 32 of
member 12 and surface 20 of member 14 to be selectively exposed to
the inert gas. Members 12 and 14 are then each respectively heated
by the use of conventional heat induction coils 50, 52.
Particularly, members 12, 14 are heated until they reach a
predetermined temperature which is substantially greater than the
melting point of material 16.
[0030] After cavity 34 is filled with the inert gas and the members
12, 14 are heated, a predetermined amount of material 16 is placed
within cavity 34, as best shown in FIG. 2. In the preferred
embodiment of the invention, material 16 is melted or liquefied
prior to its insertion within cavity 34. However, it should be
appreciated that material 16 may be placed within cavity 34 in a
substantial "solid form" or "solid state" and subsequently melted
within the cavity 34 by the use of heat induction from coil 52 and
member 14. Member 12 is then gradually inserted into cavity 34.
[0031] Since the temperature of members 12, 14 is above the melting
point of the material 16, as member 12 is inserted into cavity 34,
material 16 remains in its liquid or molten state and is displaced
around the outer surface of member 12 as the member 12 is inserted
into cavity 34. Particularly, as shown best in FIG. 3, when member
12 is fully inserted into cavity 34, material 16 substantially
fills the gap 44 formed between the outer surface 20 of member 12
and the inner surface 32 of member 14.
[0032] Once member 12 has been fully inserted into cavity 34, the
liquefied material 16 is substantially and evenly distributed
between surfaces 20 and 32. The heat provided by coil 52 is then
selectively removed or "lowered", thereby allowing heat to
dissipate from assembly 10 and reducing the temperature of members
12, 14 and material 16. As the temperature of material 16
decreases, the material 16 begins to solidify and/or harden. The
solidification of material 16 causes the material 16 to shrink or
decrease in size by a predetermined and relatively highly
predictable amount, and further causes the material 16 to bond or
attach to member 12. As the material 16 solidifies, the relatively
small, uniform and precise gap 48 is formed, thereby providing a
highly precise mating between members 12 and 14. It should be
appreciated that by casting material 16 within the engaged members
12, 14, the gap 48 is determined solely by the relatively highly
predictable, uniform and controlled shrinkage of material 16. As
such, the present invention substantially avoids the "tolerance
stacking" associated with prior art telescoping joint
assemblies.
[0033] Once material 16 has solidified, projection 30 secures
material 16 to member 12. After material 16 has solidified and
cooled, member 12 is removed from cavity 34 and a conventional and
commercially available lubricant, such as grease or oil, may be
selectively applied to the outer surface 18 of solidified material
16 and/or to the inner surface 32 of member 14 in order to reduce
sliding type friction between the engaged members 12, 14.
[0034] In one non-limiting embodiment, joint assembly 10 replaces
the traditional and previously delineated telescoping intermediate
and/or steering shaft which is resident within a vehicle steering
assembly. In this configuration, end 54 of member 12 is operatively
attached to the vehicle steering column in a conventional manner
and end 56 of member 14 is operatively attached to the vehicle gear
shaft or gearbox in a conventional manner. In this manner, the
selective torque or rotational energy, which is generated by the
steering column, is transferred and/or communicated through
assembly 10 to the gear shaft in a manner which allows the gear
shaft to concomitantly and axially articulate toward and away from
the steering column.
[0035] Particularly, as forces and/or vibrations are imparted upon
assembly 10, by way of the typical wheel suspension assembly,
member 12 selectively, telescopically, and movably penetrates
member 14 and cavity 34, thereby substantially eliminating the
relative torsional motion between member 12 and member 14, and
substantially preventing such movement, vibration, lash, or slop
from being communicated to the steering column. The axial movement
provided by assembly 10 also allows the steering column to
desirably "collapse" in the event of a collision or accident and/or
to be selectively adjusted in a telescoping manner or motion.
[0036] Importantly, the relatively tightly fitted telescoping
members 12 and 14 allow the steering column and the gear shaft to
smoothly and consistently articulate, with respect to each other,
and substantially reduces and/or eliminates "slop", "lash",
vibration, frictional losses and/or "frictional lock-up" associated
with the relatively "loose" tolerances of prior telescoping
intermediate shafts and/or steering shaft assemblies.
[0037] It should be appreciated that the assembly 10 may be
selectively used within various other applications requiring the
coupling of two axially compliant members and the transmission or
resistance of torque and/or rotational energy by and between these
coupled members. It should further be appreciated that while a pair
of shaft type members 12, 14 are shown, assembly 10, as well as the
various other coupling assemblies described herein, is adapted to
couple other types, shapes, and/or forms or members and to provide
the described coupling benefits and/or attributes to these other
coupling arrangements.
[0038] It is understood that the invention is not limited by the
exact construction or method illustrated and described above but
that various changes and/or modifications may be made without
departing from the spirit and/or the scope of Applicants'
inventions.
* * * * *