Tire uniformity machine

Details Tire uniformity machine Tire uniformity machine

1999-12-10

2001-06-12

McCall, Eric S. (Department: 2855)

Measuring and testing

Tire, tread or roadway

C073S008000, C157S016000, C157S017000, C157S018000, C157S021000

Reexamination Certificate

active

06244105

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rim holding apparatus and a rim width changing apparatus between upper and lower rims, which are applied to a tire uniformity machine.
2. Description of the Related Art
A tire uniformity machine is designed so that a tire is mounted on upper and lower spindles via upper and lower rims, and the uniformity etc. of the tire is measured by pressing a load wheel against the tire while rotating the tire around the axes of spindles. The parts of this tire uniformity machine have so far been configured as described below.
(1)
FIG. 10
shows the relationship between a spindle external fitting portion and a rim inside. The spindle external fitting portions (upper and lower locking means
115
and
116
) are arranged in parallel with the insides of rims
113
and
114
(for example, see Japanese Patent Provisional Publication No. 5-66171 (No. 66171/1993)).
(2)
FIG. 11
shows a rim drop preventive mechanism. The configuration is such that the drop of a rim
113
is prevented by using a n external hook-type drop preventive mechanism
144
to
146
attached to an external fixing side
109
of a spindle
101
(for example, see Japanese Patent Provisional Publication No. 5-66171 (No. 66171/1993)).
(3)
FIG. 12
shows a rim width changing apparatus between upper and lower rims. The configuration is such that the rim width is changed by using an external loader unit
247
to
265
and rims
213
and
214
(for example, see Japanese Patent Provisional Publication No. 3-257340 (No. 257340/1991)).
(4)
FIG. 13
shows another rim width changing apparatus between upper and lower rims. The configuration is such that only an upper rim
316
is moved vertically while being rotated with respect to an upper spindle
301
, and an offset between a centerline CL (centerline in the width direction) between upper and lower rims
316
and
333
and a centerline CW (centerline in the width direction) of a load wheel LW is corrected by vertically moving a bearing housing
303
(upper and lower spindles
301
and
308
) in the same direction (for example, see Japanese Patent Provisional Publication No. 3-188348 (No. 188348/1991)).
With the tire uniformity machine shown in
FIGS. 10
to
12
, a rim clamping device for parallel rims, which is of a hydraulic type, locks/unlocks parallel rims
113
and
114
and parallel spindles
101
and
102
by moving expanding/contracting rings
119
and
120
in relation to a piston. For this reason, during unlocking, the gap between the rim and spindle is very small (about 0.1 mm), being about 0.5 mm even in the case of expansion/contraction of a collet, for example, described in Japanese Patent Provisional Publication No. 7-190898 (No. 190898/1995). In this state, the rim is fitted onto and removed from the spindle. Therefore, when the rim is fitted or removed, positioning with accurate concentricity between the rim and spindle is needed, and also a liftable rim conveying device is needed.
On the tire uniformity machine shown in
FIG. 11
, hydraulic expanding/contracting rings
119
and
120
are used for a parallel rim holding mechanism. The expanding/contracting ring has a thickness as less as about 1 mm, so that wear and fatigue occur easily, resulting in low durability of the ring. Also, since the contact surface of the expanding/contracting ring in expansion constitutes a part of the structure, there is a risk of poor concentricity. Moreover, since the hydraulic expanding/contracting ring is held by a liquid pressure, there is a risk of poor concentricity of rim when a load is applied in the radial direction.
Also, on the above-mentioned tire uniformity machine, since the rim clamping device for parallel rims, which is of a hydraulic type, locks/unlocks the parallel rim
113
and parallel spindle
101
by moving the expanding/contracting ring in relation to the piston, there is a possibility for the parallel rim to drop when the hydraulic pressure is relieved. Therefore, the external rim drop preventive mechanism
144
to
146
is indispensable.
Also, on the above-mentioned tire uniformity machine, the fabrication of a rim fitting/removing portion wedge and the flow passage inside the ring and spindle is complicated.
Also, on the above-mentioned tire uniformity machine, the long spindle is divided into two pieces in consideration of the complicated fabrication and maintainability. When the spindle is assembled, therefore, highly accurate alignment of spindle is needed in order to ensure high rim runout accuracy.
On the tire uniformity machine shown in
FIG. 12
, when the upper and lower rim widths are changed, complicated loader movement such that the upper rim
213
is first set by an external loader and then the lower rim
214
is set is indispensable, so that much time i required for the rim width change due to the external loader unit
247
to
265
.
Also, on the tire uniformity machine shown in
FIG. 13
, since only the upper rim is moved by an adapter
317
and spindle screw
307
, the centerlines of the load wheel and tire shift from each other, which has some influence on the measurement results. Therefore, a moving mechanism must be added to the spindle itself to eliminate this shift (offset).
Also, on the above-mentioned tire uniformity machine, since only the upper rim is moved by an adapter
317
and spindle screw
307
, the adapter
317
and the spindle
301
move in the axial direction while being rotated relatively. On the other hand, an O-ring etc. must be interposed between the adapter and spindle to seal the internal pressure of rim. However, when the adapter moves in the axial direction, because of the relative rotation of the adapter and spindle, the seal is rubbed each time the rim width is changed, so that early breakage or air leakage occurs.
SUMMARY OF THE INVENTION
The present invention was made in view of the above problems, and accordingly an object thereof is to provide a highly accurate tire uniformity machine in which (1) the change of rim width and the fitting/removal of rim can be performed easily, and (2) the runout of rim can be decreased to 0.025 mm (standard) or less.
To achieve the above object, the present invention provides a tire uniformity machine in which a tire is mounted between upper and lower spindles via upper and lower rims, the tire uniformity machine being characterized in that a rim holding apparatus
10
is composed of a parallel spindle
1
which is in parallel with the axis of tire uniformity machine, a taper collet
2
formed with an inner hole
2
a
engaging concentrically with the parallel spindle
1
at the center portion thereof and a taper surface
2
b
at the outer peripheral portion thereof, a rim formed with a taper surface
3
a
engaging with the taper surface of the taper collet
2
at the inner peripheral portion thereof, a rim clamping device
4
which holds the rim
3
and is mounted so that the parallel spindle
1
is capable of being moved in the axial direction, and a fixing device
5
for determining the axial position of the rim clamping device
4
(see FIG.
1
).
In the tire uniformity machine shown in
FIG. 1
, the rim clamping device
4
may be composed of a hook
11
for holding/releasing the rim
3
by being opened/closed in the radial direction, a cylinder
12
for opening/closing the hook
11
by moving in the axial direction, a piston
14
which supports the hook
11
in such a manner as to be movable vertically and pushes the rim
3
by means of a pushing portion
18
, a spring
13
for urging the piston
14
in the ascending direction, a spring
15
for urging the cylinder
12
in the ascending direction, a clamp body
16
which holds the rim
3
, supports the piston
14
in such a manner as to be movable vertically, and is mounted so that a parallel spindle
1
is capable of being moved in the axial direction, and a pushing device
17
for pushing the cylinder
12
from the outside in the descending direction (see FIG.
2
).
The present invention provides a tire uniformity machine in which a tire i

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