JPH0521763B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a safety tire that is fitted along the outer peripheral surface of the rim inside the tire and supports the outer skin of the tire when the internal pressure of the tire decreases. Concerning children.

[Prior Art] Many safety tires have been proposed in which a tire core that supports the tire outer skin is fitted inside the tire in order to ensure safety when the internal pressure of the tire decreases due to a puncture or the like during driving.

Regarding such tire cores, for example,
Publication No. 58-185305 consists of a plurality of constituent members formed by dividing an annular body in the circumferential direction, and adjacent constituent members are separated by a lower part that protrudes in the circumferential direction from one constituent member inwardly in the radial direction. and an upper protrusion that protrudes radially outward from the other component in the circumferential direction and is in close contact vertically with the lower protrusion, which are integrated by bolts inserted radially outward. Nakako is disclosing that.

[Problem to be solved by the invention]

However, in this proposal, the bolts are exposed through holes in the outer circumferential surface of the core. , the hole tends to damage the tire skin.

Furthermore, as a tire core, it goes without saying that it has the strength to hold the tire outer skin on the outer circumferential surface, continue safe driving, and sufficiently hold the load transmitted from the tire outer skin, but it also generates noise during normal driving. It also has the following properties: it does not increase rolling resistance, it does not impede ride comfort, and when driving when internal pressure is low, there is less friction and wear with the tire outer skin, and there is no loosening of the core. requested.

An object of the present invention is to provide a core for a safety tire that satisfies these various required characteristics.

[Means to solve the problem]

The present invention is an annular core that is fitted into a rim and supports the tire outer skin when the tire internal pressure decreases, and the core has a tensile strength of 600 Kg/cm 2 or more and a compressive strength of 800 Kg/cm ² or more.
Kg/ ^cm2 or more, specific gravity 1.4 or less, stress 18.5Kg/ ^cm2 , heating deformation temperature at 150℃ or more, elastic modulus 250-1000Kg/
It consists of a plurality of structural members made of synthetic resin with a diameter of 2 mm ² , and the structural members are formed by dividing a ring body forming the core in the circumferential direction, and adjacent structural members are separated from each other by one structural member. A lower protrusion that protrudes radially inward in the circumferential direction, and an upper protrusion that protrudes radially outward from the other component in the circumferential direction and is in close contact with the lower protrusion vertically; This core for a safety tire is characterized in that it is coupled using a bolt that is inserted radially outward from the protrusion and screwed into a bottomed screw hole provided in the upper protrusion.

[Effect]

The tensile strength of the synthetic resin used for the core was increased to 600
By setting the tire to Kg/cm ² or more and having a compressive strength of 800 Kg/cm ² or more, it can have sufficient strength to support the load in the event of a tire puncture. Furthermore, if the specific gravity of the material used for the core is high, the weight of the tire will be large, so from the standpoint of fuel efficiency, the specific gravity is set at 1.4 or less. Furthermore, in the event of a puncture, the tire outer skin continues to run while being supported by the outer peripheral surface of the core, and at this time, friction occurs between the inner surface of the tire outer skin and the outer peripheral surface of the core, and heat is accumulated, e.g. The temperature on the outer surface of the core reaches 150℃. Therefore, the value of stress converted from the above load of 4000 kg on the core material is 18.5
The heating deformation temperature under the condition of Kg/ ^cm2 is at least
The temperature shall be 150℃ or higher.

In addition, the components are connected with bolts,
After the tire outer skin is installed, it is generally difficult to check the mutual bonding state of the constituent members over time unless the tire outer skin is removed from the rim.
It is important to maintain a positive bond throughout the life of the tire. Therefore, in the present invention, the elastic modulus of the core material is in the range of 250 to 1000 Kg/mm ² . If the elastic modulus exceeds 1000 Kg/mm ² , the core material will not be deformed by tightening the bolt, and the bolt will often loosen due to vibration impact, etc., and the tightening effect will be reduced. On the other hand, if the elastic modulus is less than 250 Kg/mm ² , the above-mentioned values of tensile strength and compressive strength will not be satisfied.

Furthermore, compared to using metal, the coefficient of friction against the tire outer skin is smaller, reducing the temperature rise of the core.
Furthermore, since synthetic resin is used, the frictional resistance between the tire outer skin and the core can be effectively reduced without using lubricants that are used in conventional metal cores.

In addition, since the core is connected with bolts that pass radially outward from the inner protrusion and are screwed into the bottomed screw holes in the outer protrusion, the bolts are not exposed on the outer circumferential surface. Therefore, the outer peripheral surface becomes smooth, which prevents damage to the outer skin of the tire, and even if the bolt becomes loose, it prevents the bolt from coming off, increasing safety.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Figures 1 to 3, the safety tire core E is
The rim is an annular body in which four structural members 2a, 2b, 3a, 3b made of circular arc pieces obtained by dividing the annular body into four in the circumferential direction are assembled using bolts 4, and supports the bead portion 1a of the tire outer skin 1. 6 is attached via an elastic ring 5.

In addition, in the cross section including the tire shaft, the safety tire core E smoothly connects a wide receiving part 13 with a smooth outer peripheral surface to a leg part 12 having a wide bottom surface via a narrow joint part 14. are doing.

The structural members 2a, 2b, 3a, 3b are the second
As shown in the figure, an annular body has an upper split surface a extending radially inward from the outer circumferential surface to an intermediate position in the height of the annular body, and an upper split surface a extending radially inward from the outer circumferential surface to a midpoint in the height of the annular body, and It is divided into four parts by a dividing surface consisting of a circumferential dividing surface b that extends along the diameter, and a lower dividing surface c that extends radially inward to the inner peripheral surface at the edge of this circumferential dividing surface. . Note that the dividing surfaces b in the circumferential direction extend in different directions in adjacent dividing surfaces.

As a result, the constituent members 2a, 2b are provided with lower protrusions 15 on both sides that protrude in the circumferential direction with the inner peripheral surface being the same, inwardly in the radial direction of the base made of an arcuate piece, and the constituent members 3a, 3b has a notch formed inside the base in the radial direction into which the lower protrusion 15 is inserted, and an upper part on the outside in the radial direction in which the lower protrusion and the upper and lower surfaces can be brought into close contact. A protrusion 16 is formed.

Furthermore, the lower protrusion 15 has a hole 21 that communicates with the bottomed screw hole 20 of the upper protrusion 16 in the radial direction.
is drilled, passes through the hole 21 outward in the radial direction, and is tightened with bolts 4 that are screwed into the screw hole 20 to form the integral ring body.

Note that the hole 21 is provided with a large diameter portion at its lower end into which the head 11 of the bolt 4 is inserted.

Furthermore, since the screw hole has a bottom, the bolt is not exposed to the outer circumferential surface, and the outer circumferential surface can be kept smooth.

The core is assembled inside the tire outer skin.

Furthermore, the core has a tensile strength of 600Kg/ ^cm2 or more, a compressive strength of 800Kg/cm2 ^or more, a specific gravity of 1.4 or less, and a stress of 18.5Kg/ ^cm2.
The heating deformation temperature is over 150℃, the elastic modulus is 250~1000
A synthetic resin with a weight of Kg/mm ² is used.

Tensile strength is 600Kg/ ^cm2 or more, compressive strength is 800Kg/cm2 or more.
cm ² or more is because the core has sufficient strength to support the load in the event of a tire puncture.This load is the largest load to be borne in the tire radial direction, and the tensile strength and compressive strength are Being within the above range is necessary to ensure safe driving in the event of a flat tire.

If the specific gravity of the material used for the core is high, the weight of the tire will increase, the load on the suspension will increase, and the running resistance will increase, which is undesirable from the viewpoint of fuel efficiency. Therefore, the specific gravity of the synthetic resin constituting the core component is 1.4 or less, preferably 1.2 or less.

Examples of such synthetic resins include polyethylene, polypropylene, nylon, and polyester.

Furthermore, as a general characteristic of synthetic resins, they have the disadvantage of softening due to heat. When a tire becomes flat, the outer skin of the tire continues to run while being supported by the outer peripheral surface of the core. At this time, friction occurs between the inner surface of the tire outer skin and the outer peripheral surface of the core, and heat accumulates. Temperature rises. For example, if the tire size is 13/80R20
Attached to a 8.50V x 20 rim, using nylon as the core material, the load is 4000Kg and the speed is 30Km/h.
When the drum was run for one hour with a diameter of 1707 mm, it was observed that the temperature on the outer surface of the core reached 150°C.

Therefore, this final temperature depends on the running conditions, core material,
Although it varies somewhat depending on the shape, the core material must have a heating deformation temperature of at least 150° C. under the condition of 18.5 kg/cm ² of the above-mentioned load of 4000 kg converted into stress.

Moreover, after the core is fitted onto the rim and the tire skin is attached, it is generally difficult to check the mutual bonding state of the constituent members over time unless the tire skin is removed from the rim. In order to maintain a reliable bond throughout its life, the elastic modulus of the core material should be in the range of 250 to 1000 Kg/ ^mm2 .
If the elastic modulus exceeds 1000 Kg/mm ² , the core material will not be deformed by tightening the bolt, and the bolt will often loosen due to vibration impact, etc., and the tightening effect will be reduced. On the other hand, if the elastic modulus is less than 250 Kg/mm ² , the above-mentioned values of tensile strength and compressive strength will not be satisfied.

As described above, the elastic ring 5 is attached to the inner peripheral surface of the assembled core. This elastic ring 5 has a function of fixing the bead portion 1a of the tire outer skin 1 and the core, and is made of a relatively hard rubber material. Further, the elastic ring 5 is connected to the leg portion 1 of the core.
2 and the inner surface of the bead portion of the tire outer skin 1, a U-shaped curved portion 5a is formed which bulges outward in the radial direction and keeps the gap airtight.

A rim 6 is inserted into a combination of a tire outer skin 1, a core E, and an elastic ring 5 to assemble the rim. When assembling the rim, one bead portion of the tire outer skin is brought into contact with one flange of the rim, and the inner peripheral surface of the elastic ring 5 is placed on the rim base 6a. After that, the seal ring 9 and the side ring 7 are fitted, and the lock ring 8 is fitted into the lock groove 10 while inserting the side ring 7 axially inside the rim. The lock ring 8 is a metal ring with an adjustable outer diameter and both ends are free ends.

The bead portion of the tire is fixed between the side ring 7 by the elasticity of the elastic ring 5, and safe driving can be continued even when the tire is punctured.

Furthermore, since the core is made of synthetic resin, it has a small coefficient of friction against the tire outer skin, reducing the rise in temperature of the core, and also exhibits the above-mentioned functions such as being lightweight and requiring no lubrication.

(Specific Example) A core having the following properties was manufactured, and when it was assembled into a safety tire as described above and heated, the final temperature of the outer peripheral surface of the core was 130°C. The running conditions were a load of 4000 kg, a speed of 30 km/h, and running on a drum for 1 hour.

Tire core material Nylon Tensile strength 800Kg/ ^cm2 Compressive strength 900Kg/ ^cm2 Specific gravity 117 Heating deformation temperature 160℃ (Stress 18.5Kg/ ^cm2 ) Elastic modulus 300Kg/mm [Effects of the invention] As described above, the present invention Since the core is made of synthetic resin, it is lightweight, and the frictional resistance with the tire outer skin can be significantly reduced, so deterioration of the tire outer skin due to heat generation and temperature rise can be reduced. In addition, since the core is connected with bolts that pass from the inside in the radial direction and are not exposed on the outer circumferential surface, the outer circumferential surface is smooth, preventing damage to the tire outer skin, and even if the bolts become loose. It can prevent it from coming off and improve safety.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a front view showing an assembled state of the core of the present invention, and FIG. 3 is a sectional view taken along the line A--A in FIG. 5. 1...Tire outer skin, 2a, 2b, 3a, 3b...
... Component, 4... Bolt, 5... Elastic ring,
6... Rim, 7... Side ring, 8... Rod ring, 9... Seal ring, 10... Lock groove, 20... Screw hole, 21... Hole.

Claims (1)

[Scope of Claims] 1. An annular core that is fitted into the rim and supports the tire outer skin when the tire internal pressure decreases, the core having a tensile strength of 600 Kg/cm ² or more and a compressive strength of 800.
Kg/ ^cm2 or more, specific gravity 1.4 or less, stress 18.5Kg/ ^cm2 , heating deformation temperature at 150℃ or more, elastic modulus 250-1000Kg/
It consists of a plurality of structural members made of synthetic resin with a diameter of 2 mm ² , and the structural members are formed by dividing a ring body forming the core in the circumferential direction, and adjacent structural members are separated from each other by one structural member. A lower protrusion that protrudes circumferentially inward in the radial direction, and an upper protrusion that protrudes in the circumferential direction radially outward from the other component and comes into close contact vertically with the lower protrusion; A core for a safety tire, characterized in that the core is connected using a bolt inserted radially outward from the protrusion and screwed into a bottomed screw hole provided in the upper protrusion.