U.S. patent application number 10/132951 was filed with the patent office on 2002-11-21 for apparatus for retrofitting height and load adjustable air spring to coil spring based mac pherson strut.
Invention is credited to Morrow, Joe.
Application Number | 20020171185 10/132951 |
Document ID | / |
Family ID | 25070873 |
Filed Date | 2002-11-21 |
United States Patent
Application |
20020171185 |
Kind Code |
A1 |
Morrow, Joe |
November 21, 2002 |
Apparatus for retrofitting height and load adjustable air spring to
coil spring based Mac Pherson strut
Abstract
An automotive wheel suspension comprised of a shock absorbing
strut located within a retrofit air spring which is located where
previously a standard coil was located. The air spring includes a
single, double, or triple convoluted bellow comprised of a rubber
bellow and two bead sealing rings mounted eccentrically onto the
strut by a fixed lower adapter plate. The strut is also comprised
with a rotatable upper adapter plate that allows the air spring to
take the place of the previously mounted coil spring in order to
allow load and ride height adjustment where beforehand the coil
spring allowed none.
Inventors: |
Morrow, Joe; (Mesa,
AZ) |
Correspondence
Address: |
Albert L. Schmeiser
Schmeiser, Olsen & Watts LLP
#101
18 East University Drive
Mesa
AZ
85201
US
|
Family ID: |
25070873 |
Appl. No.: |
10/132951 |
Filed: |
April 26, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10132951 |
Apr 26, 2002 |
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09764488 |
Jan 16, 2001 |
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6382602 |
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Current U.S.
Class: |
267/64.12 |
Current CPC
Class: |
B60G 15/14 20130101;
B60G 2202/152 20130101; Y10T 29/4973 20150115; B60G 15/12 20130101;
B60G 11/26 20130101; B60G 2202/314 20130101; F16F 9/04 20130101;
Y10T 29/49815 20150115 |
Class at
Publication: |
267/64.12 |
International
Class: |
F16F 005/00 |
Claims
1. An air suspension retrofit to a coil spring based strut
comprising: A shock absorbing strut having a piston rod extending
telescopically from a strut body that originally includes a coil
spring mount attached to said body; An air spring having one main
chamber comprised of a flexible rubber membrane arranged in a
single, double, or triple bellows orientation; A duo of mounts for
the air spring to seal to, which form an airtight seal about the
outside diameter of both the said strut body and the said piston
rod, the design of said mounts being such they replace the upper
and lower coil spring mounts originally equipped on vehicle; A
system of tubular spacers and or bearings to facilitate clearance
and ease mounting of said air space retrofit strut onto
vehicle.
2. A vehicle suspension system where: A set or two sets of air ride
retrofit struts are mounted in original factory locations; A
control system for said struts where the mechanism to control ride
height and or spring rate is located within the passenger
compartment so as to facilitate the driver controlling the said
suspension variables.
3. Air spring retrofit mounts that have: A design where the air
spring is mounted eccentrically to eliminate contact of the said
air spring with any portion of vehicle body; A design of said air
spring mount that is varied by strut body diameter, relation of
original coil seat mounting location to top of said strut body,
diameter of strut piston rod, and dimension of said original coil
seat; A design of said air spring mount that facilitates
construction by either casting said mount and then machining
certain features or by fabricating said mount by welding a machined
piece of tubing to a plasma cut plate in order to make a single
piece mount.
4. An air spring mounting system where: A bead-sealing ring and
said air spring mount capture a bead, located at the top and bottom
periphery of said air spring, between them. This ensures a long
life, airtight seal as opposed to a single thin band of metal
wrapped tightly around thin rubber membrane and strut body as
previously mentioned in other air spring equipped struts that are
prone to leakage and seal failure.
5. A revolving upper sealing design comprising: An upper air spring
mounting plate with a proper-machined fit to allow said strut
piston rod to easily turn within it's bored inside diameter; A duo
of o-rings located at designed dimensions of the correct size to
ensure an airtight seal yet to also allow axial movement of said
strut piston rod when vehicle is undergoing steering input.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The invention relates to automotive and light truck wheel
suspension, specifically to that of retrofitting an existing coil
spring based Mac Pherson strut and/or a standard coil over strut
wheel suspension. This enables the strut to house an air spring
where as vehicle height and spring rate is adjustable based on
driver preference and/or road conditions.
[0003] 2. Background of Prior Art
[0004] Vehicles often are originally equipped from the manufacturer
with wheel suspensions comprised of fluid shock absorber struts in
conjunction with coil spring, that are used for suspension of
vehicle weight, absorb variation in road surface, vehicle inertia,
and to maintain a pre designed vehicle ride height. In some
applications, an air spring is used in the original strut
suspension design to compensate for the transverse load the strut
experiences during jounce and rebound, and also acts to determine a
preset ride height and spring rate. In U.S. Pat. No. 4,778,198, it
is disclosed that an air spring is mounted substantially eccentric
to the strut center line in order to compensate for transverse
loading of the strut piston rod caused by jounce and rebound of the
wheel. In U.S. Pat. No. 4,911,416, it is also disclosed that an air
spring can be mounted eccentrically, offset, or at an angle to the
strut axis, the air spring can be cut at a place oblique to the
shock axis, all in order to compensate for the transverse loading
previously described. In U.S. Pat. Nos. 4,668,774/4,998,082 and
5,129,634 it is also disclosed that an air spring is mounted in
such fashion as to compensate for side load. By and large the
disclosures of these patents and the use of air springs installed
on telescoping shock-absorbing struts are intending to solve the
problem of binding by the piston rod with in the shock absorber
body.
[0005] They intend for an air spring to be part of the initial
strut design to eliminate various problems inherent in a coil
spring suspended vehicle. These patents do not, however, make
provisions for retrofitting a strut that is originally designed to
utilize a coil spring, to an air spring design. Vehicles currently
in circulation would require significant modification to utilize
any of the above patents. A better design would be to allow a
simple modification of an existing strut to house an air spring and
require no other modification to the vehicle inner fender structure
or upper strut mounting location. The only modification necessary
would be to simply exchange a coil spring strut with an air ride
retrofit strut of similar design.
[0006] Another aspect of air spring suspension known to those in
the art is the ability to compensate for increased suspension load
by various means and to vary spring rate according to vehicle
sensed road conditions including but not limited to road surface
variations, cross winds, and vehicle payload variations. In U.S.
Pat. No. 5,060,959, a system using an air or coil spring in
conjunction with an electrical motor to change ride height and or
spring rate based on data received from a multitude of sensors
located on moving suspension members. A computer system controls
the input necessary for the actuators to change ride height and or
spring rate. The computer determines the correct ride height and
spring rate based on programmed variables and input from
sensors.
[0007] Other U.S. patents including but not limited to U.S. Pat.
Nos. 4,386,791 and 4,592,540 seek to offer variable dampening or
spring rate due to rad conditions or other dynamic factors acting
upon the vehicle. These do not however, allow the driver to
infinitely control the ride height or spring rate based on the
drivers preferred road feel, handling characteristics, and also do
not allow the driver to control ride height based on aesthetic
preference. Most of these are controlled by other means such as
computers or devices that are pre calibrated. A better design for
drivers who wish to be in command of ride height or spring rage
would be one that is solely controlled by the driver from inside
the passenger compartment.
DISCLOSURE OF INVENTION
[0008] This invention embodies a Mac Pherson strut or a standard
coil strut over strut originally equipped with a coil spring seat
located on the strut body and a system of variable dimension
mounting plates and air springs. The invention seeks to allow
automobiles currently equipped with coil spring over strut style
suspension to be retrofit with an air spring strut suspension. This
invention also seeks to allow the driver to control the ride height
and spring rate based on individual preference. To retrofit an air
spring onto a Mac Pherson strut or a standard coil over strut
already equipped with provisions for a coil spring; the strut must
be properly prepared for the air spring assembly. The air spring
assembly must designed to have an airtight seal on the strut body
and on the piston rod. It must also achieve the desired dimensions
for the air bellows to operate within the designed extension and
compression. The specifics of this design will be easily
understandable when the description of the preferred embodiment is
reviewed.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a drawing of an original strut with no
modifications yet done to incorporate the air spring.
[0010] FIG. 2 is a section view of the completed air spring
assembly retrofit onto the strut.
[0011] FIG. 3 is a drawing of the completed air spring converted
strut showing only external features.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0012] Referring to FIG. 1, a strut (1) is shown in the stock
configuration that is originally equipped on the vehicle. The bump
stop seat (13) is modified by removing material from its outside
diameter until the outside diameter is slightly less than that of
the strut housing (14) in order to allow the lower air spring mount
(3, FIG. 2 & 3) to slid easily down the strut body (14). Next,
the lower spring hat (18) is removed from the strut housing (14).
Now the original strut (1) is ready to accept the air spring
conversion.
[0013] FIG. 2 is a section view of the assembled air spring
retrofit strut. Before assembling the air spring onto the strut,
the upper (5) and lower (3) air spring mounts must be manufactured
to the desired length and inside diameter based on the vehicle
specific strut housing (14) and strut piston rod (9). Once brought
to the correct dimensions, upper (5) and lower (3) air spring
mounts have upper (12) and lower (11) o-rings installed into the
machined groves on the inside diameter of the mounts (3 and 5). The
lower air spring mount (3) is slid down the strut body (14) until
it is seated on the remaining portion of the weld (16) previously
used to attach the original coil spring seat (18). The lower air
spring mount (3) is rotated about the strut body so that the air
fitting bore (15) is located perpendicular to the lower hub
mounting clevis (10) as viewed from either end of the strut. It is
also rotated to the side of the strut that is the most free of
obstruction such as anti-roll bar mounting tabs and brake line
mounting tabs. Once the lower air spring mount (3) is positioned
correctly, the lower edge of the lower air spring mount (3) seated
on the weld (16) is joined to the strut housing (14).
[0014] A fillet of silicone (17) is applied entirely around the
upper location where the strut housing (14) passes through the
lower air spring mount (3). The fillet of silicone (17) is used in
conjunction with the set of o-rings (11) to seal the lower air
spring mount (3) to the strut housing (14) in an airtight fashion.
The air spring bead sealing rings (4) are installed on to the lower
air spring (2). The air spring sub assembly is then secured to the
lower air spring mount (3) using six allen head cap screws (7) and
related nuts (6). These are equally spaced about the periphery and
tightened with such force as to produce an airtight seal between
the lower air spring mount (3) and the air spring sub assembly. The
upper air spring mount (5) is slid down the strut piston shaft (9)
until it comes to rest on the top of the air spring sub
assembly.
[0015] Now six more alien head cap screws (7) are installed through
the air spring bead sealing ring (4) and through the upper air
spring mount (5). The associated nuts (6) are tightened on to the
allen head cap screws (7) with enough force to ensure an air tight
seal between the air spring (2) and the upper air spring mount (5).
For this application, the air spring retrofit strut is now
completely assembled. However, on different applications varied by
make, model, and year of vehicle and location of strut on vehicle,
a known bearing (19) or a section of tubing (20) of a desired
inside and outside diameter having a designed length may be
installed. These components install down the piston shaft (9) to
rest upon the uppermost portion of the upper air spring mount (5).
These two components may vary in specifications from one
application to the other. The known bearing (19) serves the purpose
of allowing the completed air spring equipped strut to rotate about
the steering axis. The tubing section (20) eliminates any
interference between the known upper strut support bushing and any
portion of the air spring assembly when the section of tubing is
utilized.
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