TIRE BALANCING

EQUILIBRAGE DE PNEUS

English Abstract

A method and composition of matter for balancing tire and rim
assemblies of vehicles is disclosed wherein the composition of matter has
rounded balancing elements of different sizes to line the interior of a tire
casing
and to move over the lining to offset points of imbalance. The composition of
matter may also include a partitioning agent and a suitable desiccant.

Claims

-10-
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A balancing media for balancing a tire comprising a solid particulate
material spherical in shape having a mesh size in the range of 10-50.
2. The balancing media of claim 1 wherein the solid particulate material is
selected from the group consisting of glass, ceramics, alumina, corderite,
porcelain, titanates, and mixtures thereof.
3. The balancing media of claims 1 or 2 wherein the solid particulate
material has a density in the range of 2-5 gr/cm3.
4. The balancing media of claim 1 wherein the solid particulate material
comprises glass beads of lead-free soda lime glass.
5. The balancing media of claim 4 wherein the glass beads have a density
in the range of 2-3 gr/cm3.
6. The balancing media of claims 1, 2, 3, 4 or 5, further comprising metallic
micro-spheres having a density greater than the solid particulate material and
a
size smaller than the solid particulate material.
7. A balancing media for balancing a tire that can be poured into a valve
stem of the tire comprising balancing beads selected from the group consisting
of glass, ceramics, alumina, corderite, porcelain, titanates, and mixtures
thereof.


-11-
8. The balancing media of claim 7 wherein the balancing beads are of a
substantially rounded shape.
9. The balancing media of claim 7 wherein the balancing beads are
substantially spherical in shape.
10. The balancing media of claims 7, 8 or 9 wherein the balancing beads
have a mesh size in the range of 10-50.
11. The balancing media of claims 7, 8, 9 or 10, wherein the balancing beads
have a density in the range of 2-5 gr/cm3.
12. The balancing media of claims 7, 8, 9, 10 or 11, further comprising
metallic micro-spheres having a density greater than the balancing beads and a
size smaller than the balancing beads.
13. The balancing media of claims 6 or 12 wherein the metallic micro-
spheres are formed of atomized metallic particles.
14. The balancing media of claims 6, 12 or 13 wherein the metallic micro-
spheres are selected from the group consisting of bronze, brass, zinc, tin,
copper, stainless steel, nickel, silver, and alloys thereof.
15. The balancing media of claims 6, 12, 13 or 14, wherein the metallic
micro-spheres have a density in the range of 5-9 gr/cm3.



-12-
16. The balancing media of claims 6, 12, 13, 14 or 15, wherein the metallic
micro-spheres have a mesh size in the range of 80-325.
17. The balancing media of any one of the above claims further comprising
a partitioning agent.
18. The balancing media of claim 17 wherein the partitioning agent is a
monoclinic non-reactive crystalline mineral.
19. The balancing media of claim 17 wherein the partitioning agent is mica.
20. The balancing media of claim 17 wherein the partitioning agent is
silicone.
21. The balancing media of claim 17 wherein the partitioning agent is
Teflon R.
22. The balancing media of claim 17 wherein the partitioning agent is
vermiculite.
23. The balancing media of claim 22 wherein the partitioning agent has a
density in the range of 2-3 gr/cm3.
24. The balancing media of claims 22 or 23 wherein the partitioning agent
has a mesh size in the range of 20-325.


-13-
25. The balancing media of any one of the above claims further comprising
a desiccant.
26. The balancing media of claim 25 wherein the desiccant is silica gel.
27. The balancing media of claim 26 wherein the desiccant has a mesh size in
the range of 20-40.
28. A mixture for balancing a tire comprising: a first portion in a range of
15% to 30% by weight of the mixture of first beads of atomized metallic
particles having a specific gravity in the range 5-9 gr/cm3 and a mesh size in
the range of 80-325; and a second portion in a range of 70% to 85% by weight
of the mixture of second beads selected from the group consisting of glass,
ceramics, alumina, corderite, porcelain, and titanates having a specific
gravity
in the range of 2-5 gr/cm3 and a mesh size in the range of 10-50.
29. A mixture for balancing a tire comprising: a first portion in a range of
10% to 30% by weight of the mixture of first beads of atomized metallic
particles having a specific gravity in the range 5-9 gr/cm3 and a mesh size in
the range of 80-325; and a second portion in a range of 60% to 80% by weight
of the mixture of second beads selected from the group consisting of glass,
ceramics, alumina, corderite, porcelain and titanates having a specific
gravity in
the range of 2-5 gr/cm3 and a mesh size in the range of 10-50; and having a
third portion in the range of 5% to 15% by weight of the mixture of a


-14-
partitioning and lubricating particulate material having a specific gravity in
the
range of 2-3 gr/cm3 and a mesh size in the range of 20-325.
30. A mixture for balancing a tire comprising: a first portion in a range of
10% to 30% by weight of the mixture of first beads of atomized metallic
particles having a specific gravity in the range 5-9 gr/cm3 and a mesh size in
the range of 80-325; and a second portion in a range of 60% to 80% by weight
of the mixture of second beads selected from the group consisting of glass,
alumina, corderite, porcelain, and titanates having a specific gravity of 2-5
gr/cm3 and a mesh size in the range of 10-50; and having a third portion in
the
range of 5% to 15% by weight of the mixture of a partitioning and lubricating
particulate material having a specific gravity in the range of 2-3 gr/cm3 and
a
mesh size in the range of 20-325; and having a fourth portion in the range of
1% to 5% by weight of the mixture of a desiccating particulate matter of a
mesh
size in the range of 20-40.
31. A mixture for balancing a tire comprising: a first portion in a range of
15% to 30% by weight of the mixture of first beads of atomized metallic micro-
spheres having a specific gravity in the range 5-9 gr/cm3 and a mesh size in
the range of 80-325; and a second portion in a range of 70% to 85% of the
mixture of second beads of glass having a specific gravity of 2-5 gr/cm3 and a
mesh size in the range of 10-50.
32. A mixture for balancing a tire comprising: a first portion in a range of
10% to 30% by weight of the mixture of first beads of atomized metallic micro-




-15-



spheres having a specific gravity in the range 5-9 gr/cm3 and a mesh size in
the range of 80-325; and a second portion in a range of 60% to 80% by weight
of the mixture of second beads of glass having a specific gravity of 2-5
gr/cm3
and a mesh size in the range of 10-50; and having a third portion in the range
of 5% to 15% by weight of the mixture of vermiculite having a specific gravity
in the range of 2-3 gr/cm3 and a mesh size in the range of 20-325.

33. A mixture for balancing a tire comprising: a first portion in a range of
10% to 30% by weight of the mixture of first beads of atomized metallic micro-
spheres having a specific gravity in the range 5-9 gr/cm3 and a mesh size in
the range of 80-325; and a second portion in a range of 60% to 80% by weight
of the mixture of second beads of glass having a specific gravity of 2-5
gr/cm3
and a mesh size in the range of 10-50; and having a third portion in the range
of 5% to 15% by weight of the mixture of vermiculite having a specific gravity
in the range of 2-3 gr/cm3 and a mesh size in the range of 20-325; and having
a fourth portion in the range of 1% to 5% by weight of the mixture of silica
gel
of a mesh size in the range of 20-40.

34. A mixture for balancing a truck tire comprising, by weight: atomized
metallic micro-spheres in the range from 15% to 20% of the mixture having a
specific gravity in the range of 5-9 gr/cm3 and having a mesh size in the
range
of 80-325; glass spheres in the range of 65% to 75% of the mixture having a
specific gravity of 2-5 gr/cm3 and a mesh size in the range of 10-50;
vermiculite in the range of 7% to 12% of the mixture and having a mesh size of
20-325 and a specific gravity of 2-3 gr/cm3; and silica gel in the range of 2%
to



-16-



4% of the mixture having a mesh size in the range of 20-40.

35. A mixture for balancing a truck tire comprising, by weight: 17%
atomized metal selected from the group consisting of brass, bronze and zinc
having a specific gravity in the range of 5-9 gr/cm3 and having a mesh size in
the range of 80-325, 70%; glass beads of lead-free soda lime glass having a
specific gravity in the range of 2-5 gr/cm3 and having a mesh size in the
range
of 10-50; 10% vermiculite having a specific gravity in the range of 2-3 gr/cm3
and having a mesh size in the range of 20-325; and 3% silica gel having a mesh
size in the range of 20-40.

36. A mixture for balancing an automobile tire comprising: atomized
metallic micro-spheres in the range of 20% to 30% of the mixture by weight
having a specific gravity in the range of 5-9 gr/cm3 and having a mesh size in
the range of 80-325; glass beads in the range of 60% to 70% having a specific
gravity in the range of 2-5 gr/cm3 and having a mesh size in the range of
10-50; vermiculite in the range of 5% to 12% having a specific gravity in the
range of 2-3 gr/cm3 and having a mesh size in the range of 20-325; and silica
gel in the range of 1% to 3% having a mesh size in the range of 20-40.

37. A mixture for balancing an automobile tire comprising by weight: 24%
of atomized metallic micro-spheres selected from the group consisting of
brass,
bronze and zinc having a specific gravity in the range of 5-9 gr/cm3 and
having a mesh size in the range of 80-325; 65% of glass beads of lead-free
soda
lime glass having a specific gravity of 2-5 gr/cm3 and a mesh size in the
range



-17-



of 10-50; 9% of vermiculite having a specific gravity in the range of 2-3
gr/cm3
and having a mesh size in the range of 20-325; and 2% of silica gel having a
mesh size in the range of 20-40.

38. A method for balancing a tire rim assembly during rotation comprising
the steps of:
providing a tire rim assembly having a hollow tire casing surrounding
the space about the rim defining an interior space and having a point of
imbalance when the interior of the tire is pressurized with air;
adding a balancing media comprising solid spherically shaped
particulate material into the interior of the tire casing before or during
pressurization with air, the balancing media having a size of about 10-50
mesh;
and
rotating the tire rim assembly to distribute the balancing media within
the tire casing to offset the point of imbalance.

39. A method for continuous self balancing of a tire rim assembly during
rotation comprising the steps of:
providing a tire rim assembly having a hollow tire casing surrounding
the space about the rim defining an interior space and having a point of
imbalance when the interior of the tire is pressurized with air;
adding a balancing media comprising solid spherically shaped
particulate material into the interior of the tire casing before or during
pressurization with air, the balancing media having a size of about 10-50
mesh;
rotating the tire rim assembly to distribute the balancing media within
the tire casing; and



-18-



continuously self-balancing the tire rim assembly by rotating the
pressurized tire rim assembly and distributing the balancing media within the
tire casing so that a thicker portion of the balancing media lies opposite the
point of imbalance.

40. The method according to claims 38 or 39 wherein the solid particulate
material has a density of about 2-5 gr/cm3.

41. The method according to claims 38, 39 or 40, wherein the solid
particulate material is selected from the group consisting of glass, ceramics,
alumina, corderite, porcelain, titanates, and mixtures thereof.

42. The method according to claims 38, 39 or 40 wherein the solid
particulate material comprises glass beads.

43. The method according to any one of claims 38 to 42 wherein the
balancing media further comprises metallic micro-spheres having a density
greater than the solid particulate material and a size smaller than the solid
particulate material.

44. A method for balancing a tire rim assembly during rotation comprising,
the steps of:

providing a tire rim assembly having a hollow tire casing surrounding
the space about the rim defining an interior space and having a point of
imbalance when the interior of the tire is pressurized with air;
adding a balancing media comprising balancing beads selected from the



-19-



group consisting of glass, ceramics, alumina, corderite, porcelain, titanates,
and
mixtures thereof, into the interior of the tire casing before or during
pressurization with air; and
rotating the tire rim assembly to distribute the balancing media within
the tire casing to offset the point of imbalance.

45. A method for continuous self balancing of a tire rim assembly during
rotation comprising, the steps of:
providing a tire rim assembly having a hollow tire casing surrounding
the space about the rim defining an interior space and having a point of
imbalance when the interior of the tire is pressurized with air;
adding a balancing media comprising balancing beads selected from the
group consisting of glass, ceramics, alumina, corderite, porcelain, titanates,
and
mixtures thereof, into the interior of the tire casing before or during
pressurization with air;
rotating the tire rim assembly to distribute the balancing media within
the tire casing; and
continuously self-balancing the tire rim assembly by rotating the
pressurized tire rim assembly and distributing the balancing media within the
tire casing so that a thicker portion of the balancing media lies opposite the
point of imbalance.

46. The method according to claims 44 or 45 wherein the balancing beads
are of a substantially rounded shape.

47. The method according to claims 44 or 45 wherein the balancing beads




-20-



are substantially spherical in shape.

48. The method according to claims 44, 45, 46 or 47 wherein the balancing
beads have a mesh size in the range of 10-50.

49. The method according to claims 44, 45, 46, 47 or 48, wherein the
balancing beads have a density in the range of 2-5 gr/cm3.

50. The method according to any one of claims 44 to 49 wherein the
balancing media further comprises metallic micro-spheres having a density
greater than the balancing beads and a size smaller than the balancing beads.

51. The method according to claims 43 or 50 wherein the metallic micro-
spheres are formed of atomized metallic particles.

52. The method according to claims 43 or 50 wherein the metallic micro-
spheres are selected from the group consisting of bronze, brass, zinc, tin,
copper, stainless steel, nickel, silver, and alloys thereof.

53. The method according to claims 43, 50, 51 or 52, wherein the metallic
micro-spheres have a density in the range of 5-9 gr/cm3.

54. The method according to claims 43, 50, 51, 52 or 53, wherein the metallic
micro-spheres have a mesh size in the range of 80-325.

55. The method according to any one of claims 38 to 54 wherein the



-21-



balancing media further comprises a partitioning agent.

56. The method according to claim 55 wherein the partitioning agent is a
monoclinic non-reactive crystalline mineral.

57. The method according to claim 55 wherein the partitioning agent is
mica.

58. The method according to claim 55 wherein the partitioning agent is
silicone.

59. The method according to claim 55 wherein the partitioning agent is
Teflon®.

60. The method according to claim 55 wherein the partitioning agent is
vermiculite.

61. The method according to claim 60 wherein the partitioning agent has a
density in the range of 2-3 gr/cm3.

62. The method according to claims 60 or 61 wherein the partitioning agent
has a mesh size in the range of 20-325.

63. The method according to any one of claims 38 to 62 wherein the
balancing media further comprises a desiccant.




-22-



64. The method according to claim 63 wherein the desiccant is silica gel.

65. The method according to claim 64 wherein the desiccant has a mesh size
in the range of 20-40.

66. The method according to any one of claims 38 to 65 wherein the
balancing media is added during pressurization of the tire rim assembly.

67. The method according to any one of claims 38 to 65 wherein the
balancing media is added during the assembly of the tire and the rim.

68. A method for balancing a tire rim assembly comprising the steps of:
providing a tire rim assembly having a hollow tire casing surrounding a
space about the rim, said space to be filled and pressurized with air;
pouring a mixture into the interior of the tire casing, said mixture
comprising a first weight portion of first beads atomized metallic micro-
spheres having a first density and a first size and a second weight portion of
second beads of glass having a second density and a second size wherein said
first weight portion is less than said second weight portion, said first
density is
greater than said second density and said first size is smaller than said
second
size; and
rotating the tire rim assembly to distribute the material within the tire
casing to offset forces of imbalance.

69. The method of claim 68 in which the first portion is in a range of 10% to
30% by weight, the second portion is in a range of 60% to 80% by weight and




-23-
where the mixture includes a third portion in the range of 5% to 15% by weight
of a mixture of vermiculite having a specific gravity in the range of 2-3
gr/cm3
and a mesh size in the range of 20-325
70. The method of claim 68 in which the first is in a range of 10% to 30% by
weight, the second portion in a range of 60% to 80% by weight and where the
mixture includes a third portion in the range of 5% and 15% by weight of the
mixture of vermiculite having a specific gravity in the range of 2-3 gr/cm3
and
a mesh size in the range of 20-325 and a fourth portion in the range of 1% to
5% by weight of the mixture of silica gel of a mesh size in the range of 20-
40.
71. The method of claim 68 in which the tire casing is a truck tire where the
atomized metallic micro-spheres are in the range from 15% to 20% by weight
of the mixture, the glass beads are in the range of 65% to 75% of the mixture,
and where the mixture also includes vermiculite in the range of 7% to 12% by
weight of the mixture and silica get in the range of 2% to 4% by weight of the
mixture.
72. The method of claim 68 in which the tire casing is a truck tire where the
atomized metallic micro-spheres comprise 17% by weight and are composed of
metal selected from the group consisting of brass, bonze and zinc, the glass
beads comprise 70% by weight of lead-free soda lime glass, and further
characterized in that the mixture contains 10% by weight of vermiculite and 3%
by weight of silica gel.
73. The method of claim 68 in which the tire casing is an automobile tire and




-24-
the atomized metallic micro-spheres are in the range of 20% to 30% of the
mixture by weight, the glass beads are in the range of 60% to 70% by weight
and the mixture also contains vermiculite in the range of 5% to 12% by weight
and silica gel in the range of 1% to 3% by weight.
74. The method of claim 68 in which the tire casing is an automobile tire and
the atomized metallic micro-spheres comprise 24% by weight and are
composed of metal selected from the group consisting of brass, bronze and
zinc, the glass beads comprise 65% by weight of lead-free soda lime glass and
further characterized in that the mixture contains 9% by weight vermiculite
and 2% by weight silica gel.
75. A method for balancing a tire rim assembly comprising the steps of:
providing a tire rim assembly having a hollow tire casing surrounding a
space about the rim, said space to be filled and pressurized with air;
pouring a mixture into the interior of the tire casing, said mixture
comprising a first portion in the range of 15% to 30% by weight of the mixture
of first beads of atomized metallic micro-spheres having a specific gravity in
the range of 5-9 gr/cm3 and a mesh size in the range of 80-325; and a second
portion in a range of 70% to 85% by weight of the mixture of second beads of
glass having a specific gravity of 2-5 gr/cm3 and a mesh size in the range of
10-50; and
rotating the tire rim assembly to distribute the material with the tire
casing to offset forces of imbalance.
76. A system for maintaining a rotating tire rim assembly in balance




-25-
comprising:
a tire rim assembly having a hollow tire casing surrounding a space
about the rim and having a point of imbalance when said space is pressurized
with air; and
a balancing media located in the interior of the tire casing, wherein the
balancing media is a solid spherically shaped particulate material, the
balancing
media having a size of about 10-50 mesh, so that when the tire rim assembly is
rotated the balancing media is distributed within the tire casing so that a
thicker portion of the balancing media lies opposite the point of imbalance.
77. The system according to claim 76 wherein the solid particulate material
has a density of about 2-5 gr/cm3.
78. The system according to claims 76 or 77, wherein the solid particulate
material is selected from the group consisting of glass, ceramics, alumina,
corderite, porcelain, titanates, and mixtures thereof.
79. The system according to claims 76 or 77 wherein the solid particulate
material comprises glass beads.
80. The system according to any one of claims 76 to 79 wherein the
balancing media further comprising metallic micro-spheres having a density
greater than the solid particulate material and a size smaller than the solid
particulate material.
81. A system for maintaining a rotating tire rim assembly in balance




-26-
comprising:
a tire rim assembly having a hollow tire casing surrounding a space
about the rim and having a point of imbalance when said space is pressurized
with air; and
a balancing media located in the interior of the tire casing, wherein the
balancing media comprises balancing beads selected from the group consisting
of glass, ceramics, alumina, corderite, porcelain, titanates, and mixtures
thereof,
so that when the tire rim assembly is rotated the balancing media is
distributed
within the tire casing so that a thicker portion of the balancing media lies
opposite the point of imbalance.
82. The system according to claim 81 wherein the balancing beads are of a
substantially rounded shape.
83. The system according to claim 81 wherein the balancing beads are
substantially spherical in shape.
84. The system according to claims 81, 82 or 83 wherein the balancing beads
have a mesh size in the range of 10-50.
85. The system according to claims 81, 82, 83 or 84, wherein the balancing
beads have a density in the range of 2-5 gr/cm3.
86. The system according to any one of claims 81 to 85 wherein the
balancing media further comprises metallic micro-spheres having a density
greater than the balancing beads and a size smaller than the balancing beads.




-27-
87. The system according to claims 80 or 86 wherein the metallic micro-
spheres are formed of atomized metallic particles.
88. The system according to claims 80 or 86 wherein the metallic micro-
spheres are selected from the group consisting of bronze, brass, zinc, tin,
copper, stainless steel, nickel, silver, and alloys thereof.
89. The system according to claims 80, 86, 87 or 88, wherein the metallic
micro-spheres have a density in the range of 5-9 gr/cm3.
90. The system according to claims 80, 86, 87, 88 or 89, wherein the metallic
micro-spheres have a mesh size in the range of 80-325.
91. The system according to any one of claims 76 to 90 wherein the
balancing media further comprises a partitioning agent.
92. The system according to claim 91 wherein the partitioning agent is a
monoclinic non-reactive crystalline mineral.
93. The system according to claim 91 wherein the partitioning agent is mica.
94. The system according to claim 91 wherein the partitioning agent is
silicone.
95. The system according to claim 91 wherein the partitioning agent is




-28-
Teflon®.
96. The system according to claim 91 wherein the partitioning agent is
vermiculite.
97. The system according to claim 96 wherein the partitioning agent has a
density in the range of 2-3 gr/cm3.
98. The system according to claims 96 or 97 wherein the partitioning agent
has a mesh size in the range of 20-325.
99. The system according to any one of claims 76 to 98 wherein the
balancing media further comprises a desiccant.
100. The system according to claim 99 wherein the desiccant is silica gel.
101. The system according to claim 100 wherein the desiccant has a mesh size
in the range of 20-40.

Description

CA 02098643 2000-10-20
TIRE BALANCING
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates to an improvement in a method of
balancing tires using a free flowing material within a tire casing and in the
composition of said material.
Most tire and rim assemblies require balancing to prevent
vibration within the vehicle while it is in motion. One currently popular
method of balancing tire and rim assemblies involves rotation of the assembly
on a computerized balancing machine to determine the location and size of
weights necessary to obtain balanced rotation. Lead weights of the determined
size are then clamped to the assembly at the indicated points to complete the
balancing procedure. There are other similar "fixed weight" systems known for
tire balancing. Some disadvantages of this type of system are that tire
balancing equipment is expensive, tire balancing requires a skilled operator
and is time consuming, and tires must be rebalanced at regular intervals due
to
effects of varying tread wear.
Continuous self balancing systems overcome many of the
disadvantages of the above fixed weight systems. Continuous self balancing
systems use the principle that free flowing materials contained in a vessel in
rotation will seek a distribution in balance about the centre of rotation and
will
tend to offset, by mass damping, any imbalance inherent in the vessel. The
effectiveness of a dynamic balancing system is dependent in part on the ease
with which balancing material can move within the vessel to positions which
offset points of imbalance.


CA 02098643 2000-10-20
- 2-
In one application of this principle an annular ring is placed
circumferentially about a rim and partially filled with heavy materials that
will
flow under the influence of centrifugal force. One such balancer uses mobile
weights such as ball bearings which are free to roll to any point on the ring.
The effectiveness of this method is limited by the roundness of the ball
bearings, the concentricity of the ring to the geometric axis and the inherent
rolling resistance of the balls in the ring.
Liquids have been attempted in self balancing systems to
improve the mobility of the balancing material. U. S. 2,687,918 to Bell
discloses
an annular tube attached to a tire rim partially filled with mercury for
continuous balancing of the tire and rim assembly. Several disadvantages exist
for this method, the principal ones being high cost and toxicity of mercury,
the
difficulty of ensuring concentricity of the annular tube and the need for
special
rims.
The use of free flowing powdered materials in balancing
compensators was taught in U. S. patent 4,109,549, in which an annular tube
was filled with other dense materials such as powdered tungsten.
A different means for applying the self balancing principle was
disclosed in U. S. 5,073,217 to Fogal. A free flowing balancing powder was
placed directly within a pneumatic tire, instead of within a concentric
annular
tube. Pulverent polymeric/copolymeric synthetic plastic material in the range
of 8-12 screen size and 40-200 screen size were disclosed. The patent taught


CA 02098643 2000-10-20
- 3-
that the powder within the tire would distribute within the tire under
centrifugal forces to dampen vibration. Placing the balancing media within the
tire has two primary advantages. The balancing force is positioned close to
the
point of imbalance and extraneous annular rings are not required. The
disadvantage of Fogal is that powdered products produced from a grinder or
pulverizer tend to have particles with an irregular shape which increases
resistance or friction to fluidity. It is unlikely that heavy liquids, such as
mercury, could be substituted advantageously in Fogal's application, however,
both because of above mentioned safety reasons and because such liquids may
be incompatible with or corrosive to the composition of a tire.
It is an object of the present invention to provide a method of tire
balancing using an improved solid particulate material within a tire casing to
obtain better fluidity for more efficient balancing of a tire and rim
assembly.
The present invention uses the known principle of balancing
through mass damping and the known method of using a solid material within
a pneumatic tire to obtain a dynamic balance while the wheel is in rotation.
The
improvement of this invention lies primarily in the composition of the mixture
of the balancing material or media. A preferred size of this balancing media
is
in the approximate range of 10-50 mesh. The mixture can be comprised of a
single media or a mixture of media. In one preferred embodiment, the mixture
comprises first beads which are small, dense beads, and second beads which
are larger, less dense beads. Beads of a substantially rounded shape reduce
friction and improve the mobility of the material during balancing.


CA 02098643 2000-10-20
- 4-
The small, dense beads may be formed of atomized metallic
particles which form during atomization as tiny balls. Corrosion resistant
metal
such as bronze, brass, zinc, tin, copper, stainless steel, nickel or silver or
alloys
of same may be used. Selection may be made after consideration of factors
such as cost, availability and suitability for forming into small rounded
shapes.
In preferred embodiments the metallic component is selected from bronze,
brass or zinc and atomized to form tiny balls, hereafter called "micro-
spheres".
The micro-spheres have round surfaces which permit them to roll over each
other with less friction than sharp edged particles. The metallic micro-
spheres
have the greatest density (about 5-9 gr/cm3) of the materials in the mixture
so
that they are urged to the outside of the other materials during rotation. The
small size of the micro-spheres enables them to filter through the other
materials during rotation. The interior circumference of a tire is usually
riddled
with small pockets and ridges produced during the tire moulding process.
These surface defects can cause erratic movement of the balancing media and
thereby reduce its effectiveness. During rotation the micro-spheres are forced
against the tire casing to fill in imperfections or voids on the tire wall to
form a
smooth lining which allows the remaining balancing media to move about the
tire casing with less impediment. The excess of the micro-spheres, after voids
and ridges are levelled, act as part of the balancing material and move to
offset
points of imbalance.
The larger, less dense beads are also rounded and may be formed
from glass, ceramics, alumina, corderite, porcelain or titanates and having a
density in the range of 2-5 gr/cm3. These beads function as the primary
balancing material and form the largest portion by weight of the mixture.


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Glass spheres or beads of density 2-3 gr/cm3 are preferred. T'he glass beads
are larger but less dense than the metallic micro-spheres. Thus the glass
beads
tend to ride over the metallic micro-spheres to move easily to points of
imbalance to dampen vibrational energy. The glass beads are more durable
than thermoplastic particles of Fogal and less prone to degradation. A
preferred size range for these larger, less dense beads is 10-50 mesh.
The mixture may also include a partitioning agent, such as
vermiculite having a specific gravity in the range 2-3 gr/cm3, mica or other
monoclinic non-reactive crystalline minerals, to separate and lubricate the
mixture to enable all components of the mixture to maintain free-flowing
characteristics. Vermiculite is preferred. Other partitioning agents may be
used
to reduce the friction of the balancing media, for example, a lubricant can be
applied to the surface of the media. Such a friction reducing agent could
include
silicone that is sprayed or otherwise applied to the balancing media.
Alternatively, the friction reducing agent may be applied to the interior of
the
tire such that it coats the tire rim assembly. Other friction reducing agents,
such
as Teflon, or the like, may be used in lieu of, or in addition to, silicone.
A suitable desiccant, such as silica gel, A1203, CaCl2 or CaS04
may be added to the mixture to prevent agglomeration in the presence of
moisture. Silica Gel is preferred as a desiccant to maintain a dry atmosphere
in
the tire casing. The small particles used in this type of balancing system
tend to
be hydroscopic and may agglomerate in the presence of moisture.
Agglomerated particles will cause a dramatic reduction in balancing
efficiency.
The silica gel tends to ameliorate this condition.


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A preferred mixture of this invention is as follows.
MATERIAL SIZE CONCENTRATION
Non-ferrous atomized metal 80-325 mesh 10-30%
(e.g., bronze or brass)
Glass beads 10-50 mesh 40-85%
(Lead-free soda lime type)
Vermiculite 20-325 mesh 10-30%
Silica Gel 20-40 mesh 2-5%
It has been found that this invention will work effectively with
any conventional mufti-wheel vehicle tire and rim assembly. It will be
appreciated, however, that the amount of material to balance a particular
assembly will vary in quantity and proportion, according to the type of
assembly and the size of the tire and rim assembly. Correct amounts and
proportions may be determined empirically by persons skilled having the
benefit of this disclosure and the current state of the art. To illustrate in
general
terms, a steering tire of a truck (11 x 24.5) may require about 400 grams
while a
truck driving tire may require 500 grams of the mixture. Automobile tires may
require only 160 grams of the mixture but are much more sensitive to
vibration than truck tires and therefore require more vehicle specific and


CA 02098643 2000-10-20
_ 7_
careful measuring.
BRIEF DESCRIPTION OF THE DRAWINGS
In the figures which illustrate a preferred embodiment of this
invention:
Figure 1 is an illustration of a tire and rim assembly cut away to
show the interior of the tire casing having the balancing material of this
invention;
Figure 2 is an illustration of a cross section of a tire and rim
assembly showing the balancing material of this invention; and
Figure 3 is a side sectional view of a tire showing the distribution
of the mixture of this invention.
DETAILED DESCRIPTION OF THE DRAWINGS
In the figures illustrating this invention like numerals indicate like
elements.
In Figure 1, a tire (1) is shown mounted on a rim (2) which, in
turn, is mounted on an axle (3) of a vehicle (4). The interior of the tire
casing (5)
is ordinarily filled with air. The balancing material (6) of this invention
lies
about the periphery of the tire casing (5) while the wheel is in rotation by


CA 02098643 2000-10-20
- 8-
reason of the centrifugal force exerted on the material (6).
As illustrated in Figure 2, the interior of the tire casing (5) has
many voids and surface irregularities (7) (which are accentuated in the
illustration).
The atomized metal micro-spheres (8) are shown to lie in and
about the surface irregularities (7) of the tire casing (5). The micro-spheres
(8)
fill the voids and surface irregularities (7) and form a smooth, slippery
surface
for movement of the remainder of the balancing material. The excess of the
micro-spheres acts as balancing material. Glass beads (9) roll over the micro-
spheres (8) and act as the primary balancing material. Vermiculite (not shown)
and silica gel (not shown) are interspersed in the material to act as a
lubricant
and a desiccant, respectively.
The preferred proportions of the balancing mixture for use in
truck tires is as follows:
atomized metal 17%
glass beads 70%
vermiculite 10%
silica gel 3%
For automobile tires, the preferred mixture is:
micro-spheres 24%


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glass beads 65%


vermiculite 9%


silica gel 2%


In operation, the balancing mixture may be poured into a new
tire casing as it is assembled onto a rim. In tire rim assemblies previously
constructed, the sealing bead about the rim may be broken and the mixture
poured into the tire casing. Alternatively the mixture may be poured into the
valve stem or mixed with the air which pressurizes the tire. Once a tire on a
vehicle begins to rotate, the balancing material (6) distributes itself within
the
tire casing (5). As the speed of rotation increases, the metallic micro-
spheres (8)
tend to filter to the outside adjacent the tire casing and to fill the voids
and
surface irregularities (7), thereby forming a smooth inner surface. The
lighter
and larger glass spheres (9) then roll over the micro-spheres to adjust to a
position opposite a point of imbalance (10).
As illustrated in Figure 3, the material (6) distributes within the
tire casing (5) so that a thicker portion of the material (6) lies opposite
the point
of imbalance (10), while some of the balancing material (6) is distributed
about
the entire inner surface of the tire casing (5). The distribution of the
balancing
material (6) acts as mass damping to overcome the eccentric force which would
otherwise be introduced by the point of imbalance (10), so that the tire (1)
turns smoothly.

Representative Drawing