Measuring and testing – Tire – tread or roadway
Reexamination Certificate
1998-10-13
2001-05-29
McCall, Eric S. (Department: 2855)
Measuring and testing
Tire, tread or roadway
Reexamination Certificate
active
06237402
ABSTRACT:
TECHNICAL FIELD
This invention relates to a method for correcting the radial runout of a tire and rim wheel assembly. More particularly, the method corrects ride vibration problems associated with large tires and rims specifically designed for off-road or agricultural use. The method corrects or minimizes the radial runout of farm tires and their two piece rim wheel assembly.
BACKGROUND ART
Large tires for tractors and the like vehicles are conventionally mounted on large two piece rims. The radially outer portion is an annular ring commonly referred to as the rim. The rim is adapted to hold the tire. The rim has a 5° bead seat, a pair of axially out flanges, and a drop center portion to facilitate mounting the tire over the flange portions. This annular ring further has a radially inner flange with a plurality of clearance holes to which the second portion of the rim is attached.
The second portion of the rim is a disk which has a central opening which preferably is tapered, this central opening engages the drive axle of the vehicle to which it is attached. The drive axle preferably is a tapered male end and when attached to the disk portion of the rim both parts have their respective axis of rotations substantially coincident.
Radially outward of the central opening is a plurality of holes which can be aligned with the openings of the rim and bolted to the rim by means of threaded fasteners.
These attachment holes in both the rim and the disk portion each have a clearance or relatively larger opening to accept the threaded fasteners. These dimensional tolerances permit the mounted tire and rim assembly to have their respective axis of rotation to be shifted relative to the common axis of the vehicle axle and wheel disk assembly. This ability to shift the relative position of the mounted tire and rim assembly relative to the disk portion can be positively beneficial in reducing tire and rim assembly vibration on tractors and the like vehicles. These vibration amplitudes are most disturbing on hard paved surfaces when the tractors are driven at relatively high speeds in excess of 30 km/h.
The prior art methods to correct this tire wheel assembly vibration characteristic involves numerous required steps of locating a maximum radial runout location, deflating the tire, breaking down the beads and rotating the tire to a distinct, precise location on the rim, reinflating the tire and remounting the tire rim assembly. This method of vibration reduction is commonly referred to as match mounting. When precisely accomplished the desired resultant vibration reduction can be achieved. The match mounting method is inherently time consuming, requires the tire beads to be detached from the rim, often times the fluid medium is a liquid which must be captured and reinjected into the tire, and after completing this procedure if not properly conducted the desired reduction in vibration will not result.
DISCLOSURE OF INVENTION
This invention relates to a method for minimizing the radial runout of a tire and rim assembly
10
, the rim
12
having an outer annular rim
20
and a disk
22
attached to the outer rim
20
by threaded fasteners
24
. The inventive method can be summarized by the following steps:
locating the position of maximum radial runout and measuring the amount of maximum radial runout;
loosening the threaded fasteners
24
;
moving the disk
22
radially toward the location of the maximum radial runout a distance one-half the measured maximum runout amount, and then tightening the thread fasteners
24
thereby securely attaching the disk
22
to the tire
14
and outer rim
20
of the assembly.
The step of locating and measuring the maximum runout preferably can be accomplished by rotating the tire and rim assembly
10
about an axis of rotation. For example, the tractor like vehicle can be jacked up or placed on a lift whereby the normally inflated and unloaded tire
14
can be freely rotated. A runout measuring device
30
is used to locate the maximum runout location
2
preferably the runout device can be zeroed at that location
2
and rotated to read the runout at a location
4
approximately 180° from the maximum runout location
2
. This measured runout is considered for the purposes of this invention to be the amount of radial runout. The preferred device
30
preferably automatically indicates one-half the total amount of runout. This “one-half amount” is useful because it is the exact amount of adjustment that is required to zero the runout of the tire rim assembly
10
. These two locations
2
,
4
are marked and in the most preferred method the operator then rotates the tire rim assembly
10
such that the location where rim disk
22
central opening
26
is contacting the axle
11
is oriented at the vertical or on top of the axle
11
, in other words at a 12:00 o'clock orientation. The axle
11
and the disk
22
are both marked at that location
6
, prior to removing the tire and rim assembly. After removing the tire and rim assembly
10
the assembly
10
is positioned in a horizontal position, preferably over a support device
40
. Then, an apparatus
50
for precisely moving the disk
22
is inserted into the support device
40
and a pusher bar
52
on the apparatus
50
is placed in proximity to the opening
26
of the central disk
22
at a location aligned with the maximum radial runout mark
2
and the 180° location
4
. Each of the threaded fasteners
24
are loosened such that the disk
22
and the rim
20
are free to accept relative movement. Prior to moving the disk
22
, a device
60
for measuring the relative movement of the disk in relation to the tire
14
and rim
12
is placed in position aligned between the radial runout mark
2
and the 180° mark
4
. The displacement of the dial indicator arm is parallel to a line extending from
2
,
4
. The dial indicator can be placed anywhere so long as the arm is parallel to the line
2
,
4
. Preferably, measuring the device
60
includes a dial indicator
62
that can be set to the amount of displacement required which is precisely one-half the amount of the measured runout. The operator can then actuate the apparatus
50
which advances the pusher bar
52
which moves the disk
22
toward the location
2
of the maximum runout. At the point where the dial indicator
62
reads zero the disk
22
movement is stopped and the threaded fasteners
24
are retightened. The assembly
10
is then reattached to the axle
11
making sure that the axle
11
and disk
22
marks
6
are in the top vertical or 12:00 o'clock position. At this point the tire rim assembly
10
will have been assembled minimizing the first harmonic radial runout.
Definitions
For ease of understanding this disclosure the following terms are disclosed:
“Aspect Ratio” means the ratio of the tire's section height to its section width.
“Axial” and “axially” means the lines or directions that are parallel to the axis of rotation of the tire.
“Bounce” or “Hop” means the vertical acceleration related to first Harmonic Radial Runout or Force Variation of each tire and rim assembly interacting with the other tire and rim assemblies of the vehicle.
“Circumferential” means lines or directions extending along the perimeter of the surface of the annular tire parallel to the equatorial plane EP and perpendicular to the axial direction.
“Design Rim” means a rim having a specified configuration and width. For the purposes of this specification, the design rim and design rim width are as specified by the industry standards in effect in the location in which the tire is made. For example, in the United States, the design rims are as specified by the Tire and Rim Association. In Europe, the rims are as specified in the European Tyre and Rim Technical Organization—Standards Manual and the term design rim means the same as the standard measurement rims. In Japan, the standard organization is The Japan Automobile Tire Manufacturer's Association.
“Equatorial Plane (EP)” means the plane perpendicular to the tire's axis of rotation an
King David L
McCall Eric S.
The Goodyear Tire & Rubber Company
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