JPH06127207A - Tire and rim assembly - Google Patents

Abstract

PURPOSE:To provide a non-puncture tire with the same cushion and durability as a pneumatic tire without regulating pneumatic pressure. CONSTITUTION:In a tire T, a foamed elastic body 4 with independent bubbles is provided in an inner cavity 6 formed with an assembly of a toroidal wire 2 and a use rim 1. In the foamed elastic body 4, the length of it at its center line is roughly equal to the peripheral length at the center line of the inner cavity 6 of the tire and rim assembly. Also it is formed with a bar or doughnut body of which ratio of VM/VT, VM being the volume of the foamed elastic body 4 and VT being the volume of the inner cavity 6 of the tire and rim assembly T, is 1.45 to 2.00. In addition, the foamed elastic body 4 is sealed in the inner cavity 6 of the tire and rim assembly T in compressed condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called non-puncture tire in which a foam elastic body for retaining a tire shape is enclosed instead of gas in a tire / rim assembly having a pressure chamber for enclosing air or a gas instead thereof.

[0002]

2. Description of the Prior Art Among pneumatic tires, pneumatic tires for agriculture, especially pneumatic tires for rice transplanters, are used for about 3 weeks a year, and the rest of them are storage periods. , At the time of use in the next year, air may escape and you may not be able to drive. This is because the tire size is small and the tire cavity volume is small. Further, among motor sports, in a rally or an off-road race that runs in a desert or a mud, there are many cases in which pneumatic tires cause a flat tire to interfere with running. As a measure against such a decrease in air pressure or puncture, there are methods such as installing a core in the tire cavity or installing a puncture sealing material. Further, a sponge material is arranged outside the tube (Japanese Patent Laid-Open No. 3-2.
No. 31008) or a so-called hollow tire in which the inside of the tire wheel is hollow, and there is one that achieves both free maintenance of internal pressure and riding comfort.

[0003]

Although the above-mentioned first one is effective as an emergency measure, it is impossible to continue the operation and to perform the work without repairing the tire tube or supplementing the internal pressure. Is required. The second
In the second one, the volume of the air chamber becomes smaller, and the air escapes during the storage period, which also requires maintenance. Further, the last one has a problem in durability since the load is supported by the hollow pipe-shaped wheel portion and the rubber adhesive portion. As described above, each of the conventional flat tires has a problem.
An object of the present invention is to provide a flat tire having the same cushioning property and durability as a pneumatic tire without adjusting so-called air pressure.

[0004]

In order to achieve the above object, in the tire / rim assembly of the present invention, a foamed elastic body having closed cells is formed by an assembly of a toroidal tire and a rim to be used. Make a tire for the lumen,
The foamed elastic body has a length at the center position substantially equal to the circumferential length at the center position of the inner cavity of the tire / rim assembly, and the ratio of the volume V _{M to} the volume V _T of the inner cavity of the assembly V _M / V
There is provided a rod-shaped or donut-shaped body having _T in the range of 1.45 to 2.00, wherein the foamed elastic body thus formed is compressed and sealed in the inner cavity of the assembly.

In the tire-rim assembly having the above-mentioned characteristics, the foaming rate of the foamed elastic body of closed cells enclosed in the inner cavity formed by the assembly of the toroidal tire and the rim used is determined by the following equation. Foaming rate = V ′ / V × 100 = (G−G ′) / G × 100 = 1
00 to 900, where V is the volume of the solid portion of the foamed elastic body that does not include the bubble portion, V ′ is the volume of the gas portion of the foamed elastic body, G is the specific gravity of the solid itself (not include the bubble portion), G ′ is the foamed elasticity. Specific gravity of the whole body (including air bubbles)

[0006]

The operation of the tire / rim assembly having the above structure will be described below. (1) General functions and effects Since a closed-cell foam is adopted as the elastic body enclosed in the tire / rim assembly, the air chamber has a large number of air chambers unlike one general tube. Air permeation can be reduced, it can be used for several years without adjusting the air pressure, and it will not be punctured even if nails are inserted. Also, since the enclosed elastic body is made of closed-cell foam, the air inside the bubbles is volume-compressed by the load, and it is possible to have a vertical spring constant (rigidity) that is almost the same as that of a pneumatic tire. Unlike ordinary rubber solid tires, good cushioning properties can be secured. Furthermore, regarding durability, by obtaining a vertical spring constant (rigidity) similar to that of a pneumatic tire, durability equivalent to that of a pneumatic tire can be secured, and the durability problem of hollow tires described above is solved. It

(2) Problems of the foamed elastic body itself in the tire / rim assembly When the longitudinal spring constant (rigidity) close to that of a pneumatic tire cannot be obtained, for example, when it is used for rice transplanters, A large amount of mud enters the rim and the tire, and the tire is largely deformed when a lateral force is input, which is not preferable. Therefore, in order to obtain a longitudinal spring constant (rigidity) close to that of a pneumatic tire, the foamed elastic body in the tire / rim assembly has a volume of the inner cavity of the tire / rim assembly (hereinafter, referred to as cavity volume) V _T. However, if it is necessary to have a volume of more than 1.45 times, and if it exceeds 2.0 times, the rim assembly becomes difficult with the usual method, and it cannot be used in actual use.

In order to prevent large deformation due to the above-mentioned longitudinal spring constant (rigidity) or mud intrusion into the rim or the tire and lateral force input, the axial direction in the radial cross section of the bore of the tire / rim assembly. The width SW of the foamed elastic body with respect to the width (hereinafter referred to as the cavity width) W _T is SW>
1.2W _T is preferable, and if SW <1.2W _T , there is a concern that the tire / rim assembly may lack rigidity, and if SW <2.0W _T , rim assembly becomes difficult.
Practicality is poor. In consideration of the above points, and further considering the cost, in order to obtain an efficient effect with a volume as small as possible, the width SW of the foam elastic body in its cross section is SW ≧ SH with respect to its height SH, The width of the elastic foam is the axial width W of the tire
_It is recommended to set it in correspondence with _T and to enclose it. Because SH has an effect in the radial direction of the tire in the static state, but has little effect in the lateral direction and has little effect in the dynamic state of the tire, SW <SH ensures sufficient performance. Because it requires a larger volume.

(3) Foaming Ratio of Foamed Elastic Body In order to secure good cushioning property by obtaining a vertical spring close to a pneumatic tire, the foaming ratio of the foamed elastic body should be at least 100% or more as described above. If it exceeds 900%, there is a problem in production such that the surface of the foamed elastic body is excessively tensioned and the surface is severely cracked, which is not preferable. (4) Material of foamed elastic body In consideration of cost, rubber is the most preferable material, and other elastomer material such as urethane may be used.

[0010]

EXAMPLES Examples will be described with reference to the drawings. 1A and 1B are views showing a rod-shaped foam elastic body and a donut-shaped foam elastic body, respectively. FIG. 2 is a sectional view showing a state in which the foamed elastic body is set in the inner cavity formed by the assembly of the tire and the rim. FIG. 3 is a view in which a foamed elastic body having a circular cross section is superposed on a cross section of an assembly in which a tire and a rim are combined. FIG. 4 is a diagram in which the width SW of the foamed elastic body in its cross section is superimposed on the cross section of the assembly in which the tire and the rim are combined with the foamed elastic body having a shape of SW> SH with respect to its height SH.

FIG. 1 (a) is a rod-shaped foamed elastic body having closed cells enclosed in an inner cavity formed by an assembly in which a toroidal tire and a rim are combined, and a foamed rubber is used as its material. Is best, other urethane, etc.
Any elastomer may be used. FIG. 1B shows a doughnut-shaped foamed elastic body made of the same material. The tire shown in FIG. 2 is an agricultural tire, and has an inner cavity 6 of a tire casing 2 in which a lug 3 is formed on a rim 1.
1 (a) or (b) of a cross section larger than that cross section.
After the rod-like or donut-like foamed elastic body 4 is compressed and enclosed, the bead 5 side of the tire casing 2 is seated on the rim 1 to complete the assembly of the tire / rim assembly T. With such a structure, air does not escape even when it is not used for a long period of time, and mud does not enter the inner cavity 6 even during traveling on mud, and durability can be secured. In addition, the code | symbol 5 shows a bead.

The sectional shape of the foamed elastic body compressed and enclosed in the tire / rim assembly T is shown in FIGS. 3 and 4.
3 has a shape as shown in FIG. 3, and in FIG. 3, the height SH with respect to the maximum width SW in the foam elastic body 4 is SW> SH with respect to the cross section of the tire / rim assembly T in which the tire casing 2 is seated on the rim. FIG. 4 shows a case in which the cross-sectional shape of the foamed elastic body 4 is larger than the cross-sectional shape of the tire casing 2 with respect to the shape of the tire casing 2 seated on the rim 1. It is a stack of cross sections. In short, the cross section of the foamed elastic body 2 is a cross section having a size as shown in the figure with respect to the cross section in the state where the tire casing 2 is seated on the rim 1, and the foamed elastic body 2 has a length at the center position, The circumferential length of the tire / rim assembly T at the center of the inner cavity is substantially equal to that of the foamed elastic body 2
The ratio V _M / V _T of relative volume V _T of the tire-rim assembly T of the volume V _M are prepared to be in the range of 1.45 to 2.00, it is a tire-rim assembly in the lumen 6 of the three-dimensional T It is compressed and enclosed.

Next, a tire / rim assembly having a tire size of AGS2-50-17 and a rim size of 140 × 17 was used as an example to fabricate a foamed elastic body corresponding to the tire / rim assembly, which was compressed into the tire / rim assembly. As a result of enclosing and assembling, and comparing and comparing with Comparative Example and a pneumatic tire, the following results were obtained.

(1) Specifications of foamed elastic body, mud penetration into tire / rim assembly and results of vertical spring test

(2) Durability test results The tires of Examples 1 and 2, the pneumatic tire and the hollow tire were applied with a load of 175 kg on the drum and run at a speed of 15 km / h. The results are as follows. From the results of the above tests, the tire / rim assembly of the present invention is mainly used as an agricultural tire, in which mud does not enter the tire casing, and the vertical spring constant is almost the same as that of the pneumatic tire. It was also found that the durability was at least as good as that of a pneumatic tire. Needless to say, similar effects can be obtained not only for agricultural tires but also for tires of this kind.

[0016]

Since the present invention is configured as described above in detail, it is not necessary to adjust the air pressure unlike a pneumatic tire, and it has at least the same cushioning property and durability as a pneumatic tire. It is possible to provide an effect such as providing a flat tire.

[Brief description of drawings]

FIG. 1A is a perspective view of a rod-shaped foamed elastic body enclosed in a tire / rim assembly. (B) is a perspective view of a donut-shaped foamed elastic body enclosed in the tire / rim assembly.

FIG. 2 is a cross-sectional view showing a state where a foamed elastic body is set in a cavity formed by an assembly of a tire and a rim.

FIG. 3 is a diagram in which a width SW in a cross section of a foamed elastic body is SW> SH with respect to a height SH, and a foamed elastic body having a shape of SW> SH is superimposed on a cross section of a tire / rim assembly in which a tire and a rim are combined. .

FIG. 4 is a view in which a foamed elastic body having a circular cross section is superposed on a cross section of a tire / rim assembly in which a tire and a rim are combined.

[Explanation of symbols]

 1 rim 2 tire casing 3 lug 4 foamed elastic body 5 bead 6 cavity between tire casing 2 and rim 1

Claims (1)

[Claims] 1. A tire provided with a foamed elastic body having closed cells in an inner cavity formed by an assembly of a toroidal tire and a used rim, wherein the foamed elastic body has a length at a center position. A rod-like or donut having a circumference Vm at the center position of the lumen of the rim assembly, and a ratio V _M / V _{T of} its volume V _{M to} the volume V _T of the assembly lumen is in the range of 1.45 to 2.00. A tire / rim assembly comprising a foamed elastic body formed in this manner and having a foamed elastic body thus formed enclosed in the inner cavity of the above-mentioned assembly on the back of compression.