U.S. patent application number 09/737061 was filed with the patent office on 2002-06-20 for robust, low mass stabilizer bar link assembly.
Invention is credited to Bhandiwad, Manoj V., Hauser, Kurt K., Kincaid, Jeffrey Lee.
Application Number | 20020074761 09/737061 |
Document ID | / |
Family ID | 24962420 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020074761 |
Kind Code |
A1 |
Kincaid, Jeffrey Lee ; et
al. |
June 20, 2002 |
Robust, low mass stabilizer bar link assembly
Abstract
An end link adapted to interconnect a stabilizer bar and a
suspension member within a vehicular suspension system includes a
housing having a first socket, a second socket and a body
interconnecting the first and second sockets. The end link also
includes a first joint assembly pivotally interconnecting the first
socket and the stabilizer bar and a second joint assembly pivotally
interconnecting the second socket and the suspension member The
first socket includes a net-shaped cavity to receive the first
joint assembly.
Inventors: |
Kincaid, Jeffrey Lee;
(Clarkston, MI) ; Bhandiwad, Manoj V.; (West
Bloomfield, MI) ; Hauser, Kurt K.; (Northville,
MI) |
Correspondence
Address: |
Harness, Dickey & Pierce, P.L.C.
P. O. Box 828
Bloomfield Hills
MI
48303
US
|
Family ID: |
24962420 |
Appl. No.: |
09/737061 |
Filed: |
December 14, 2000 |
Current U.S.
Class: |
280/124.152 ;
280/93.51 |
Current CPC
Class: |
Y10T 29/49259 20150115;
B60G 2204/1224 20130101; B60G 2204/416 20130101; B60G 2204/422
20130101; Y10T 29/49918 20150115; B60G 7/005 20130101; B60G 2206/11
20130101; B60G 21/0551 20130101; B60G 2206/8101 20130101; F16C
11/0638 20130101; F16C 2326/05 20130101; Y10T 29/49853
20150115 |
Class at
Publication: |
280/124.152 ;
280/93.51 |
International
Class: |
B60G 003/02; B60G
009/04; B62D 007/20 |
Claims
What is claimed is:
1. An end link adapted to interconnect a stabilizer bar and a
suspension member within a vehicular suspension system, the end
link comprising: a housing having a first socket, a second socket
and a body interconnecting said first and second sockets; a first
joint assembly pivotally interconnecting said first socket and the
stabilizer bar; a second joint assembly pivotally interconnecting
said second socket and the suspension member, said first socket
including a net-shaped cavity to receive said first joint
assembly.
2. The end link of claim 1 wherein said first joint assembly
includes a ball stud having a ball segment and a shank segment,
said first joint assembly further including a support mechanism for
pivotally supporting said ball segment within said first
socket.
3. The end link of claim 2 wherein said shank segment is coupled to
said stabilizer bar.
4. The end link of claim 3 wherein said net-shaped cavity includes
a first bore having a first size and a second bore having a larger
size, said support mechanism including a lower bearing positioned
within said first bore and an upper bearing positioned within said
second bore.
5. The end link of claim 4 wherein said lower bearing is press fit
within said first bore.
6. The end link of claim 5 wherein said upper bearing has an outer
surface spaced apart from an inner wall of said second bore.
7. The end link of claim 6 wherein said upper bearing includes a
plurality of fingers biasedly engaged with said ball segment.
8. The end link of claim 7 wherein said first joint assembly
includes an end cap positioned within a third bore of said
net-shaped cavity, said first socket having a portion thereof
deformed to retain said end cap within said third bore.
9. The end link of claim 1 wherein said housing is cast from an
aluminum alloy containing magnesium in the range of .0.19 to .0.29
percent.
10. The end link of claim 9 wherein said housing exhibits
elongation greater than eight percent under load.
11. A suspension system for a motor vehicle comprising: a
stabilizer bar; a suspension member; an end link interconnecting
said stabilizer bar and said suspension member, said end link
including a housing having first and second net-shaped cavities,
said end link further including a first joint assembly positioned
in said first cavity to interconnect said stabilizer bar and said
end link and a second joint assembly positioned in said second
cavity to interconnect said suspension member and said end
link.
12. The suspension system of claim 11 wherein said housing includes
a generally cylindrical body having a first socket integrally
formed at one end and a second socket integrally formed at the
other end, said first socket defining said first net-shaped cavity
and said second socket defining said second net-shaped cavity.
13. The end link of claim 12 wherein said first joint assembly
includes a ball stud having a ball segment and a shank segment,
said first joint assembly further including a support mechanism for
pivotally supporting said ball segment within said first
socket.
14. The end link of claim 13 wherein said shank segment is coupled
to said stabilizer bar.
15. The end link of claim 14 wherein said net-shaped cavity
includes a first bore having a first size and a second bore having
a larger size, said support mechanism including a lower bearing
positioned within said first bore and an upper bearing positioned
within said second bore.
16. The end link of claim 15 wherein said upper bearing includes a
plurality of fingers biasedly engaged with said ball segment.
17. The end link of claim 11 wherein said housing is cast from an
aluminum alloy containing magnesium in the range of .0.19 to .0.29
percent.
18. The end link of claim 10 wherein said housing exhibits
elongation greater than eight percent under load.
19. A method of constructing an end link for a vehicle suspension,
the method comprising: die casting a housing having a first socket,
a second socket and a body interconnecting said first and second
sockets; positioning a first joint assembly within said first
socket wherein said first socket is in an as-cast condition;
positioning a second joint assembly within said second socket
wherein said second socket is in an as-cast condition; and
retaining said first and second joints within said first and second
sockets.
20. The method of constructing an end link of claim 19 wherein the
step of retaining said first joint includes deforming a portion of
said first socket to resist withdrawal of said first joint from
said first socket.
21. The method of constructing an end link of claim 20 wherein the
step of die casting includes positioning a parting line proximate
said portion to be deformed.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to a suspension system for
motor vehicles and, more particularly, to an end link for
connecting a stabilizer bar to a control arm of the suspension
system.
[0003] 2. Discussion
[0004] It is common practice for motor vehicles to be equipped with
independent suspension systems for absorbing road shock and other
vibrations while providing a smooth and comfortable ride for the
vehicle occupants. In suspension systems of this type, a stabilizer
bar is often used to increase the roll rigidity and improve the
steering stability of the vehicle. Typically, the stabilizer bar is
a rod-shaped member having an elongated central segment oriented to
extend laterally across the vehicle and an arm segment extending
longitudinally at each end of the central segment to form a
generally U-shaped configuration. The central segment of the
stabilizer bar is supported for rotation about its own longitudinal
access by one or more mounting brackets which are fixed to the
vehicle body or frame. Most commonly, the mounting brackets are
positioned in close proximity to the arm segments to minimize any
bending moments which may be induced into the stabilizer bar. The
distal end of each arm segment is coupled to a control arm of the
suspension system by an end link. When the vehicle is subjected to
a lateral rolling force such as, for example, while the vehicle
negotiates a turn, the arm segments pivot in opposite directions
with respect to the longitudinal access of the central segment. As
a result, torsional reaction forces are generated which act through
the arm segments to urge the control arms to move toward their
normal position. Thus, the vehicle body will be prevented from
excessive rolling or leaning to either side by the torsional
resistance produced by the stabilizer bar. As noted, end links are
used to interconnect the distal end of each arm segment of the
stabilizer bar to corresponding control arms. The end links
function to accommodate the relative angular movement between the
stabilizer bar and the control arm caused by the suspension
traveling through its range of motion. Stabilizer bars are
typically manufactured with an end form (i.e., eye-form or
apertured panel) at each end which is adapted to receive a fastener
extending from the end link. Some end links are of the "silent
block" type and include a threaded fastener, such as a bolt, which
extends through a sleeved rubber grommet and the end form. A lock
nut is used to secure the bolt to the end form. Another type of
link, commonly referred to as a "direct-acting" end link, is
equipped with a ball joint for providing a quicker and stiffer
response to suspension motion. In direct-acting links, a threaded
shank of a ball stud extends through the end form and is likewise
secured thereto using a lock nut.
[0005] Unfortunately, some existing end links have been downsized
and cost analyzed such that they no longer provide adequate fatigue
strength and toughness. As such, particular emphasis has been
directed toward developing a robust, low mass stabilizer bar link
assembly. In order for such a robust link assembly to be
economically feasible, the cost of manufacture must be curtailed.
Accordingly, the need exists for a device which provides for the
requisite relative angular movement between components while
exhibiting low weight in combination with superior fatigue strength
and toughness.
SUMMARY OF THE INVENTION
[0006] Accordingly, an objective of the present invention is to
provide an anti-roll system for a motor vehicle's suspension having
a robust, low mass stabilizer bar link assembly.
[0007] Another object of the present invention is to provide a
net-shaped end link housing requiring little to no machining after
casting.
[0008] As further object, a retention mechanism functions to
rigidly secure a threaded shank segment of the ball stud within the
end link housing. The retention mechanism includes an upper bearing
having integrally molded fingers designed to compensate for
dimensional variations within the as cast housing.
[0009] Accordingly, the present invention provides an end link
adapted to interconnect a stabilizer bar and a suspension member
within a vehicular suspension system. The end link includes a
housing having a first socket, a second socket and a body
interconnecting the first and second sockets. The end link also
includes a first joint assembly pivotally interconnecting the first
socket and the stabilizer bar and a second joint assembly pivotally
interconnecting the second socket and the suspension member The
first socket includes a net-shaped cavity to receive the first
joint assembly.
[0010] Further objects, features and advantages of the invention
will become apparent from a consideration of the following
description and the appended claims when taken in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of an exemplary independent
front wheel suspension including a robust low mass stabilizer bar
link assembly of the present invention;
[0012] FIG. 2 is a sectional view of a portion of the stabilizer
bar link assembly;
[0013] FIG. 3 is an exploded perspective view of the link
assembly;
[0014] FIG. 4 is a partial sectional view of a housing casting of
the link assembly of the present invention; and
[0015] FIG. 5 is a partial cross-sectional view of the link
assembly constructed in accordance with the teachings of the
present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0016] In general, the present invention is directed to an end link
for connecting a stabilizer bar to a suspension member, such as a
control arm, in a vehicle suspension. The end link of the present
invention is adapted to replace most conventional end links and to
provide improved performance without requiring modification of the
other components associated with the vehicle suspension. Thus, the
end link of the present invention may be utilized with a wide
variety of suspension systems and is not intended to be limited to
the particular application described herein.
[0017] With reference to FIG. 1, and independent front wheel
suspension system is generally indicated at reference numeral 10.
Suspension 10 is of the type having upper and lower control arms
and a strut assembly at each wheel which are suspended from a
vehicle frame. It should be appreciated that reference will be made
to a vehicle frame, yet those skilled in the art will recognize
that many current vehicles do not have a frame as such but instead
have regions of the body which act as an integrated frame
structure. With this in mind, frame 12 is shown to partially
include a pair of longitudinal side rails 14 and a cross beam
16.
[0018] Suspension system 10 includes a long lower control arm 18
and a short upper control arm 20 which are both pivotally attached
to frame 12. A strut assembly having a helical coil spring 22 and a
strut damper 24 is retained between an intermediate portion of
lower control arm 18 and frame 12 to support the weight of the
vehicle and any loads which are transmitted through lower control
arm 18. Upper control arm 20 is connected to lower control arm 18
by a steering knuckle 26. A hub and rotor assembly 28 is rotatably
attached to a spindle portion (not shown) of steering knuckle 26
such that a wheel and tire "not shown" may be mounted thereon.
Suspension system 10 further includes a stabilizer bar 30 having a
elongated central segment 32 which extends laterally across the
vehicle, and a pair of arm segments 34 which extend longitudinally
along the vehicle at each end of central segment 32. Central
segment 32 is rotatably attached to frame rails 14 by a pair of
mounting brackets 36. A distal end 38 of each arm segment 34 is
connected to a corresponding lower control arm 18 by an end link 40
constructed in accordance with the teachings of the present
invention.
[0019] With reference to FIGS. 2 and 3, end link 40 is fastened to
stabilizer bar 30 at one end and to lower control arm 18 at its
opposite end. In general, the embodiment shown is symmetrical about
a horizontal plane, identified by construction line "A". Each end
of link 40 is assembled from a set of components including two ball
joint assemblies 42 and 42' which are interconnected by a housing
44. Due to the similarity of the components associated with the
ball joint assembly 42 with respect to the components of ball joint
assembly 42', its components are identified with the same reference
numerals except having a primed designation. Ball joint assembly 42
includes a lower bearing 46, a ball stud 48, an upper bearing 50
and a disc-shaped end cap 52. Each of the ball joint components are
disposed within a socket 54 integrally formed at an end of housing
44. Housing 44 also includes a generally cylindrical body 55
interconnecting sockets 54 and 54'. A boot 56 sealingly
interconnects ball stud 48 and socket 54.
[0020] With reference to FIGS. 4 and 5, socket 54 includes a side
wall 58 and an end wall 60 defining a cavity 62. End wall 60
includes an aperture 64 extending therethrough. Side wall 58 is
cast to define three-stepped bores namely, first bore 66, second
bore 68 and third bore 70. It should be appreciated by those
skilled in the art that because housing 44 is created by a casting
process, each of the bores includes a draft angle to assure removal
of housing 54 from the tool.
[0021] As noted earlier, an object of the present invention is to
utilize housing 44 in a net-shape or as-cast condition.
Specifically, bores 66, 68 and 70 are in their net shape upon
removal of housing 44 from the die casting tool. No supplemental
machining or forming is performed to modify the bore geometry. As
such, lower bearing 46 is configured to accommodate the as-cast
surface finishes and tolerances while securely aligning and
retaining ball stud 48. Lower bearing 46 includes a generally
cylindrical outer surface 72, a substantially spherical inner
surface 74 and a stop face 76.
[0022] Ball stud 48 includes a shank segment 78 and a ball segment
80 interconnected by an integral flange segment 82.
[0023] During assembly of ball joint assembly 42, lower bearing 46
is disposed within cavity 62 and axially displaced within first
bore 66 until stop face 76 abuts end wall 60. It should be
appreciated that spherical inner surface 74 of lower bearing 46
extends slightly past center. Therefore, as shank segment 78 is
disposed within aperture 64, ball segment 80 must be snap fit
within lower bearing 46. Once lower bearing 46 and ball stud 48
have been positioned as shown in FIG. 5, upper bearing 50 is
positioned within second bore 68. Upper bearing 50 includes a
generally cylindrical wall 83 having an outer surface 84. A
plurality of fingers 86 radially extend from wall 83. Each of
fingers 86 includes a generally spherical contact surface 88.
During installation, end cap 52 is forced into contact with a top
face 90 of wall 83 thereby forcing surfaces 88 into contact with
ball segment 80. It should be appreciated that outer surface 84 is
offset from third bore 70 and upper bearing 50 may float within
cavity 62 as is required.
[0024] To complete construction of ball joint assembly 42, end cap
52 is forced into contact with a land 92 within cavity 62. While
contact is maintained between end cap 52 and land 92, a portion of
side wall 58 is mechanically deformed to retain end cap 52 along
with each of the aforementioned components within cavity 62. After
mechanical deformation, portion 93 contacts end cap 52 as shown in
FIG. 5. At this time, boot 56 is positioned over shank segment 78
to surround a neck 94 of ball segment 80.
[0025] In the preferred embodiment, housing 44 is constructed from
a modified Aluminum Association 365.0 aluminum alloy. One skilled
in the art should appreciate that the process of die casting
typically does not provide components exhibiting high toughness and
ductility. On the contrary, aluminum die castings typically exhibit
ductility in the 1 to 3% elongation range. End link 40 of
suspension system 10 is loaded during vehicle operation in a manner
that typically requires a minimum of approximately 8-12%
elongation. An increase in ductility is also required to
mechanically deform side wall 58 in the manner previously described
to retain end cap 52 without the use of external fasteners. It has
been discovered that a tradeoff between material properties exists
and magnesium content. As magnesium content is increased, the die
cast component exhibits higher hardness and higher fatigue life. As
magnesium is reduced, toughness and ductility are increased. To
obtain the optimum compromise of toughness, ductility, fatigue
strength and hardness, the Aluminum Association 365.0 aluminum
alloy composition was modified to define a new alloy having a
magnesium content ranging from .0.19-.0.29%.
[0026] Additionally, a mold parting line 96 has been positioned to
assure that optimum material properties are present in the
mechanical deformation area of side wall 58. Specifically, and in
reference to FIG. 5, mold parting line 96 has been offset from the
component centerline to the top of the component in order to
optimize material properties and allow for a proper mechanical
deformation of portion 93 of side wall 58. Also, body 55 maintains
a relatively thicker section than bowls 54 to assure that the
material properties found within the bowls are as near optimum as
possible.
[0027] The foregoing discussion discloses and describes merely
exemplary embodiments of the present invention. One skilled in the
art will readily recognize from such discussion, and from the
accompanying drawings and claims, that various changes,
modifications and variations may be made therein without departing
from the spirit and scope of the invention as defined in the
following claims.
* * * * *