JPH0352361B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to a runflat tire wheel for a track running vehicle, and the track running vehicle herein refers to a run-flat tire wheel for a track running vehicle.
For example, dedicated running paths (tracks) such as monorails and guideways run relatively short distances (e.g., several kilometers).
It is used for the so-called new transportation system, which is a means of mass transportation, often by train, that is laid over a distance of about 10 to 10 km) and connects multiple points separated from each other and runs round and round on the above-mentioned track. Runflat refers to a vehicle with a pneumatic tire that may undesirably occur during driving, which is convenient for ensuring the excellent ride comfort required for this type of vehicle. Even if the wheel load loses its ability to bear the internal pressure due to a certain air leak (e.g. due to a puncture), it is possible to continue the operation over a short distance (e.g. about 20 km) until reaching the repair facility without virtually any hindrance. The purpose of this invention is to propose a run-flat tire wheel for a track running vehicle that is improved so as to be able to smoothly ensure continuous operation under such run-flat conditions. (Prior art) Regarding this type of run-flat tire wheel,
For example, a precedent example can be found in Japanese Patent Application Laid-Open No. 54-6205. However, in this case, the solid annular member of elastic material, which is placed between the rigid crown and the rim as a retaining ring for the tire, has an outer diameter approximately equal to the inner diameter of the rigid crown, and after installation of the tire, this annular member is having an inner diameter and width such that compression of the elastic material of the member ensures fixation of the assembly of the annular member and the rigid crown on the rim;
Although the size characteristics are mainly mentioned, the physical properties of the elastic material, which are more important for ensuring smooth continuous operation of the vehicle over the necessary mileage under runflat conditions, are not mentioned. (Problem to be Solved by the Invention) The present invention advantageously fulfills its mission as a run-flat tire wheel for a track running vehicle, that is, when a run-flat condition occurs, there is no problem with the continued operation of the vehicle and subsequent forwarding. Not only is it possible to reach a repair facility for an air leak failure without any hindrance, but also without causing damage to the wheel tire under this continued operation, and thus maintaining the runflat function of the tire under both uses. It is an object of the invention to propose a runflat tire wheel for track vehicles which can be easily recovered. (Means for Solving the Problems) The present invention includes a tubeless type pneumatic tire, a flat base type rim, and a tubeless type pneumatic tire fitted to the flat base of the rim between the inner surfaces of a pair of bead portions of the tire. A run-flat tire wheel comprising an assembly of an annular rubber pad and a rigid core formed by connecting metal segments having an I-shaped cross section in an annular manner around the annular rubber pad and integrating the rim with the annular rubber pad. The annular rubber pad has a circumferential groove on its outer peripheral surface that tightly fits the inner peripheral flange of the rigid core, and holds the rigid core stably.
The JIS hardness is 60~90°, the dynamic elastic modulus is 50~200Kg f/cm2 under the measurement conditions of 20℃-2%, and the loss tangent is also 50~200Kg ^f / ^cm2 .
A runflat tire wheel for a track running vehicle characterized by having physical property values within a range of 0.125 to 0.350. FIG. 1 shows a run-flat tire wheel for a track running vehicle according to the present invention in a cross section including its rotating shaft. , 3 is an annular rubber pad, and R is a rim, particularly of a flat base type, on which the pneumatic tire 1 is mounted. The means for reinforcing the pneumatic tire 1 may remain conventional, and therefore all reinforcing elements appearing in its cross section are omitted from illustration. The rigid core 2 is formed by connecting metal segments having an I-shaped cross section in an annular shape, and has an outer diameter smaller than the inner diameter of the tread portion of the pneumatic tire 1 and occupies an inner cavity thereof. 3 is an annular rubber pad which will be described in detail later, and R is a rim having a fixed flange _F1 and a combination flange _F2 at both ends of the flat base _R1 . Now, the inner diameter d of the annular rubber pad 3 is 97.4 to 99.8 with respect to the outer diameter D of the flat base _R1 of the rim R.
%, more preferably in the range of 98% to 99.6%, and fit onto the flat base of the rim R. This is because if it is less than 97.4%, it will be difficult to assemble, but if it exceeds 99.8%, wrinkles will easily occur on the outer or inner periphery of the annular rubber pad, reducing its durability, and the precision of the rigid core 2. This is because it cannot be fixed well. Next, the width w of the annular rubber pad 3 is relative to the distance W between the inner surfaces of the bead portions of the pneumatic tire 1 after the rim is assembled.
It should be set in the range of 100 to 112%, more preferably 102 to 110%, because if it is less than 100%, the bead will tend to move during runflat running, resulting in a decrease in runflat running performance. On the other hand, if it exceeds 112%, assembly becomes difficult. Furthermore, the thickness of the sheet portion of the annular rubber pad 3, that is, the residual thickness t ₁ at the bottom of the circumferential groove, which will be described later, is the same as that of the rigid core 2.
The height H is set in the range of 6 to 18%, more preferably 8 to 15%, because if it is less than 6%, the cushioning effect will be insufficient and the runflat running performance will be adversely affected, and assembly will be difficult. On the other hand, the displacement under the external force acting on the rigid core 2 during runflat running exceeding 18% is large, and this generates heat, which reduces the life of the annular rubber pad 3 and the inner surface of the bead of the pneumatic tire 1. This is because it will have a negative impact. The annular rubber pad 3 has a circumferential groove 3' on its outer peripheral surface at the center in the width direction, into which the inner circumferential flange 2' of the rigid core 2 is tightly fitted. It has a width b and a depth g corresponding to the circumferential flange 2'. This circumferential groove 3' facilitates accurate positioning of the rigid core 2 between the inner surfaces of the bead portions of the pneumatic tire 1, that is, in the central area of the flat base _R1 of the rim R, prior to rim assembly. It is useful for assembly and stable holding and fixing, and is essential for preventing left and right movement of the rigid core 2 during runflat running, maintaining the durability of the annular rubber pad 3, and improving runflat running performance. The optimum width b of the circumferential groove 3' is 59.5 to 65.2% of the width of the annular rubber pad 3, preferably 60.5 to 65.2%,
64.5% and should be in the range of 98-100.5%, more preferably 99-100% of the width B of the inner flange 2' of the rigid core 2, which means that if it is less than 98%, the width B of the inner flange 2'' is not well settled and the fixation tends to become unstable, which has a negative effect on runflat running performance.On the other hand, if it exceeds 100.5%, the displacement of the rigid core 2 becomes large when a lateral force is applied during runflat running. Therefore, not only does the durability of the annular rubber pad 3 decrease, but also it becomes difficult to fix the rigid core 2 during assembly. The rigid core 2 is preferably made of a light alloy such as aluminum alloy, and the rigid core 2 has, for example, I-shaped cross-sectional segments divided into five parts on the circumference, and is bolted to a pair of arc-shaped side plates 4 somewhat similar to rail joint plates. 5 allows it to be fixed with screws. Needless to say, the outer peripheral flange 2'' of the rigid core 2 has an outer diameter of such a degree that it does not come into contact with the inner surface of the pneumatic tire 1 when the tire wheel rolls under load for general running. The important rubber physical properties of the annular rubber pad 3 are JIS hardness of 60° to 90° (Shorer hardness of 63° to 93°), preferably 65° to 90°.
It is necessary to set the angle within the range of 80°, because if it is less than 60°, the deformation during runflat running will be large, while if it exceeds 90°, it will be difficult to assemble the workability and the appropriate cushioning required during runflat running. This is because it is unfavorable from the standpoint of effectiveness. Next, regarding the dynamic elastic modulus at 20℃ and 2%
50Kgf/ ^cm2 to 200Kgf/ ^cm2 , preferably 100Kgf/cm2
It is necessary to set it in the range of cm ² to 180 Kgf/cm ² .If it exceeds 200 Kgf/cm ² , it is unfavorable from the cutting surface, and if it is less than 50 Kgf/cm ² , the deformation becomes excessive.
Furthermore, the loss tangent tanδ is 0.125 to 0.350, preferably
The range of 0.150 to 0.300 must be limited due to heat generation issues. In order to reduce the friction between the inner surface of the tire 1 and the outer peripheral flange of the rigid core 2 during runflat running, 400 to 500 g of the following lubricant is sealed in the inner cavity of the pneumatic tire 1. This lubricant has the following characteristics:
composition is preferred. Characteristics: A lubricant composition that has semi-solid properties and thixotropic properties near greenhouses, especially at high temperatures (100℃
Preferably, the shear viscosity at temperatures above) is lower than that at room temperature. That is, when the shear rate is 10 to 20 sec ^-1 , the shear viscosity at room temperature is in the range of 20000 to 200000 cP, and
The shear viscosity at 150°C is in the range of 2000 to 20000 cP. Composition: Typical lubricant compositions include mineral oil-based, synthetic oil-based liquid to semi-solid lubricants, or powder-based solid lubricant compositions, but in the case of this invention,
When applied to the inner surface of a tire, it must not affect the inner rubber and must be able to withstand high-load friction. In order to satisfy these properties, it is preferable to use a material that has a polarity different from that of rubber and is in a liquid to semi-solid state. The main ingredients are synthetic oils such as diester oil, silicone oil, Yukon oil, and halocarbon oil, and among them are metal soap, silica, bentone, allyl urea, indanthrene, phthalocyanine, graphite, molybdenum disulfide, and phthalocyanine. An example is a lubricant composition containing additives such as a thickener such as a base resin, an antioxidant, and a rust preventive agent. (Function) The annular rubber pad has a circumferential groove on its outer circumferential surface that closely fits the inner circumferential flange of the rigid core, which helps in easy assembly of the rigid core with accurate positioning, and also contributes to stable holding and fixing. This prevents the rigid core from moving to the left or right during runflat running, increases the durability of the annular rubber pad, and improves runflat running performance. The contribution of the above physical property values of the annular rubber pad 3 under runflat conditions of the pneumatic tire 1 is as follows. JIS hardness: To help buffer the external force transmitted from the tread through the rigid core 2 when the pneumatic tire 1 is rolling under runflat conditions with the tread inner surface of the pneumatic tire 1 in contact with the outer peripheral flange 2'' of the rigid core 2. The JIS hardness of the annular rubber pad 3 has a limit of 90°, and if this is exceeded, damage is likely to occur on the inner surface of the tread, which not only makes it impossible to complete the predetermined runflat mileage, but also makes it impossible to reuse the pneumatic tire 1. In this sense, It is preferable for the JIS hardness to be low, but if the value is lower than 60°, the annular rubber part itself will deform excessively, making it difficult to hold the rigid core 2 stably. The results of the tests using the rubber are summarized in Figure 2. Dynamic modulus of elasticity: Regarding the deformation resistance shown in Figure 2, the dynamic elastic modulus is similar to the rubber hardness as shown in Figure 3. The lower limit is 50Kgf/ ^cm2 ,
If the height exceeds 200Kgf/cm ² , cracks will easily form in the inner corners of the circumferential groove of the annular rubber pad 3, which will hinder the stable holding of the rigid core 2 and make it impossible to complete continuous operation under runflat conditions. . The experimental results regarding this relationship are shown in FIG. Loss tangent Mainly related to the heat generation of the annular rubber pad 3, and if it exceeds 0.35, rubber deterioration is likely to occur due to significant temperature rise.
It should be noted that a loss tangent of less than 0.10 cannot be put to practical use in carbon black formulations. Regarding this relationship, Figure 4 shows the results of an investigation into the influence of heat generation. In the above experiment, the deformation resistance of the annular rubber pad 3 was tested by applying a runflat tire according to the present invention to a test drum at a load of 4000 kg and a speed of 4000 kg.
The tire was run flat at a speed of 35 km/hr, and judgment was made based on the distance at which it became impossible to run due to a reduction in the holding effect of the rigid core 2 due to the deformation of the annular rubber pad 3. Regarding the cushioning effect, the pneumatic tire 1 was tested in the same manner.
The cut resistance was evaluated based on the running distance at which runflat running became unstable due to cracks occurring at the corners of the circumferential groove of the annular rubber pad 3. (Example) In the illustrated example using a tubeless tire of tire size 13/80R20, the inner diameter d of the annular rubber pad 3 is:
Since the outer diameter D of flat base R ₁ is 508 mm, it is 505 mm, which is 99.4% of this, and the width w is 163 mm, which is 107.9% of this, since the distance W between the inner surfaces of the bead parts of tire 1 is 151 mm. Since the height H of the rigid core 2 is 158 mm, t ₁ is 15 mm, which is 9.5% of this. It is preferable that both end surfaces of the annular rubber pad 3 substantially follow the inner surface shape of the bead portion of the pneumatic tire 1 as shown in the figure, so the width w is shown as an average width. As for the rubber physical properties of the annular rubber pad 3, the JIS hardness is 70°, the dynamic elastic modulus is 175Kgf/cm ² , and the loss tangent is
0.252 was used. On the other hand, a circumferential groove 3' is formed on the outer periphery of the annular rubber pad 3 so that the inner circumferential flange 2' of the rigid core ₂ is located in the center of the width of the rim R, that is, in the central area of the flat base R1. Both sides of the inner peripheral flange 2' of No. 2 shall have a groove width and a groove depth to which they substantially fit, and here the width b of the peripheral groove 3'
is 99.5 mm, the width B of the inner flange 2' is 100 mm, the groove depth g is 13 mm, and the side thickness S of the inner flange 2'
is 10mm. Incidentally, the groove depth g is preferably set in a range of 50 to 150%, more preferably 80 to 135%, of the side surface thickness S of the inner peripheral flange 2'. The assembled inner diameter of the inner peripheral flange 2' is matched to the groove bottom diameter of the peripheral groove 3' of the annular rubber pad 3. The rim R comprises a flat space R ₁ and a fixed flange F ₁ at one axial end thereof and a mating flange F ₂ at the other end, so that after assembly of the rigid core 2 in the internal cavity of the pneumatic tire 1, Combine this with the annular rubber pad 3, then pass the flat base _R1 of the rim R through the annular rubber pad 3 from the bead on one side, and combine the through end and restrain it with the flange F2. easily done. Air is injected by arranging circumferentially continuous small grooves P, P' in the inner surface of the annular rubber pad 3 and the groove bottom of the circumferential groove 3', such as semicircular or rectangular shapes suitable for air passages, and making them communicate at multiple locations. By placing the liquid in the pneumatic tire 1, it can be easily injected into the pneumatic tire 1 through the diagonal hole 7 provided in the rigid core 2. Using a pneumatic tubeless tire of size 13/80R20 described above and a commercially available flat base type rim of size 9.00×20, a common rigid core is used for the embodiments of this invention, including the inclusion of the lubricant described above. Comparative tests were conducted on the influence of the shape and physical properties of the annular rubber pad in conjunction with the comparative example shown in Table 1, and the effects of the present invention were confirmed. The specifications and rubber properties of both annular rubber pads are summarized in Table 1 below.

【table】

【table】

[Table] Note that runflat running conditions are internal pressure 0 kg/cm ²
The load was 4000Kg and the speed was 35Km/hr. (Effects of the Invention) The run-flat tire for track running vehicles of the present invention has a rigid core that is located in the internal cavity of the pneumatic tire and supports the wheel load under run-flat conditions by taking over the filling internal pressure of the pneumatic tire. The annular rubber pad that is held and fixed on the flat base of the rim has a circumferential groove on its outer circumferential surface that tightly fits the inner peripheral flange of the rigid core, and is used to stably hold and fix the rigid core. This prevents the rubber pad from moving, maintains the durability of the annular rubber pad, and improves runflat running performance. In addition, by specifically adapting the physical properties of the rubber, it is possible to secure sufficient continuous operation and vehicle transfer distance required under runflat conditions, and the pneumatic tires themselves due to such operation can be Damage can be advantageously avoided,
After repair to restore runflat function, there is no problem in using both pneumatic tires.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the example, Figure 2 is a graph of the relationship between the hardness of the annular rubber pad, resistance to deformation, and cushioning effect, and Figure 3 is a graph of the relationship between dynamic elastic modulus, resistance to deformation, and cut resistance. The graph shown in FIG. 4 is also a graph of the relationship between loss tangent and heat generation. 1...Pneumatic tire, 2...Rigid core, 3...
...Annular rubber pad, R...Rim, _R1 ...Flat base.

Claims (1)

[Scope of Claims] 1. A tubeless type pneumatic tire, a flat base type rim, an annular rubber pad fitted to the flat base of the rim between the inner surfaces of a pair of bead portions of the tire, and
In a run-flat type wheel comprising an assembly of a rigid core which is formed by connecting metal segments having an I-shaped cross section in an annular manner around the annular rubber pad and integrating the rim through the annular rubber pad, the annular rubber pad has the following features: The outer circumferential surface has a circumferential groove that tightly fits the inner circumferential flange of the rigid core to hold the rigid core stably, and it also supports dynamic measurement under the measurement conditions of JIS hardness of 60 to 90° and 20°C - 2%. Elastic modulus is 50-200Kg ^f /cm ² , loss tangent is 0.125
A runflat tire wheel for a track running vehicle, characterized in that it has physical property values within the range of ~0.350.