JPH04164630A - Solid tire - Google Patents

Abstract

PURPOSE:To obtain a solid tire which can improve load-resistant ability and make vibration low, by a method wherein the subject tire is constituted of a base rubber layer and tread rubber layer and the base rubber is comprised by making use of a compression-molded annular body beforehand by a mold for base rubber molding. CONSTITUTION:This solid tire 1 is provided with a base rubber layer 2 positioning at the innermost side of a radial direction of the tire and a tread rubber layer 3 positioning at the outside of the radial direction of the tire. Annular body 5 which is of rigid rubber reinforced with a short-fiber cord and molded beforehand with a base rubber mold is used for a base rubber mold 2. Rubber mixed with a short-fiber for the base rubber is molded into a sheet with a calender roll, then packed with a packing made of polyvinyl and wound round is wound round a tire former and a coil body is formed. The coil body is removed from the former, after heating of the same, the same is put into the mold for base rubber molding and the annular body 5 whose inside and outside for formation of the stepless base rubber layer 2 is free form a step is formed by pressure of a press.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid tire, and more particularly to a solid tire with improved tire uniformity.

[Prior art]

In general, solid tires are required to have excellent performance such as load-bearing capacity, low heat generation, and uniform durability.An important factor is that the prints can be placed low, and cost reduction is required. be done. On the other hand, as shown in Fig. 3, pneumatic solid tires use hard rubber reinforced with short fibers for the base part a, and J-type solid tires for the tread part.
A two-layer structure is known in which the base part a is made of a softer rubber with an ISA hardness of 60 to 70. In addition, in recent years, as shown in Fig. 4, fiber-filled rubber has been applied to a crusher roll and then rolled into a sheet shape, for example, a sheet s with a thickness of 5 mm in a calendering process, which is then wound on a forming former to form the base part a. A coiled type is used.

[Problem to be solved by the invention]

However, when such a coiled sheet is wound around a homer, a step (1) occurs between the beginning and the end of the sheet. In addition, a green tire is formed by wrapping a rubber sheet for the tread part on a base rubber made of a coil body with a step T, and then vulcanizing it to form a tire. In this case, the step t of the hard base rubber still remains, and the longitudinal stiffness of the tire is partially different. Such tires with non-uniform rigidity have a problem in that the vehicle vibrates violently when the vehicle is driven.

An object of the present invention is to provide a solid tire that can increase load-bearing capacity and reduce vibration.

[Means to solve the problem]

The present invention consists of a base rubber layer made of rubber located on the innermost radial side of the tire and reinforced with short fiber cords, and a tread rubber layer located on the outside in the radial direction, and the base rubber layer is used for base rubber molding. This is a solid tire that uses a ring-shaped body that has been compression-molded in advance using a mold.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, a solid tire 1 of the present invention includes a base rubber layer 2 located on the innermost side in the tire radial direction, and a tread rubber layer 3 located on the outer side in the radial direction.

The base rubber layer 2 is made of hard rubber reinforced with short fiber cords, and uses a ring-shaped body 5 that has been molded in advance using a base rubber mold.

As the short fiber cord, in addition to organic fiber cords such as polyester, nylon, and rayon, inorganic fiber cords such as glass and steel are preferably cut into lengths of 10 mm or less.

Note that in order to reduce product costs, case materials used in pneumatic tires or case materials recovered from waste tires may be cut into predetermined lengths using a crusher mill or the like.

Note that the thickness TB of the base rubber layer 2 is in the range of 20 to 70%, preferably 25 to 45% of the tire cross-sectional height TH. If the value is less than 20%, the fitting pressure with the rim cannot be maintained, while if it exceeds 70%, the cushioning properties will be significantly reduced. In addition, the short fiber cord is 4 parts per 100 parts by weight of rubber.
It is mixed in an amount of 0 parts by weight or less, preferably 5 to 35 parts by weight. This short fiber-containing rubber for the base rubber is formed into a sheet with a thickness of 5 mm and a width of 200 mm, for example, using a calendar roll.The sheet is then backed with polyvinyl and wound, and then placed on the tire homer with a predetermined thickness. Wrap it until it becomes
A coil body 6 shown in FIG. 4 is formed.

Thereafter, this coil body 6 is removed from the homer, preheated in an oven to about 60 to 50°C, and then placed in a base rubber mold (not shown) and pressed to form a base rubber layer 2 without any steps. Ring-shaped body 5 with no difference between inner and outer surfaces for forming
(Fig. 2). After setting the annular body 5 on the homer again, a tread rubber sheet is wrapped around the outer surface of the annular body 5 and vulcanization molding is performed to form the base rubber layer 2 and the tread rubber layer 3. Molding a tire having

The tread rubber layer 3 uses rubber with a JISA hardness of 50 to 700, and is made of a rubber composition with excellent wear resistance, crack resistance, and grip properties, such as diene rubber such as natural rubber, isoprene rubber, and styrene-butadiene rubber. A so-called tread rubber compound, in which a predetermined amount of carbon is blended with rubber, is used. If the JIS hardness is less than 50H3, the wear resistance will be poor, and if the JIS hardness exceeds 70H3, the grip performance will be reduced. Further, the thickness TC of the tread rubber layer 3 is in the range of 30 to 80% of the tire cross-sectional height TH. The thickness TC of the tread rubber layer 3 correlates with the service life due to wear of the solid tire 1, and increasing the thickness can extend the service life. Note that an intermediate rubber layer (not shown) may be interposed between the base rubber layer 2 and the tread rubber layer 3. As the intermediate rubber layer, a rubber having a JISA hardness of 65 to 80H3 and harder than the tread rubber 3 is used. Conventional tires with a three-layer structure use rubber with low energy loss for the intermediate rubber layer, but heat generation is reduced by using hard rubber and suppressing the amount of deformation. Therefore, even if a rubber material with low resilience is used, the amount of deformation is small, so the amount of heat generated is small, the degree of freedom in selecting the rubber material is high, and product costs can be reduced. On the other hand, since the intermediate rubber layer has a high rubber hardness, there is less deformation under high loads, and the load-bearing capacity is improved, and pitching and rolling properties are also reduced, making it easier for forklifts to handle cargo.

In order to prevent cracks from occurring due to sudden changes in rigidity at the interfaces between the base rubber layer, tread rubber layer, and intermediate rubber layer, it is desirable that the difference in JISA hardness between adjacent rubbers be 8H8 or less.

As shown above, the solid tire of the present invention uses a perfectly circular annular body 5 in which the base rubber layer that fits on the rim is compression molded in a press mold, so that on the circumference of the tire, Rigidity is uniform, making it possible to significantly reduce vibrations caused by tires while driving.

〔Example〕

A solid tire with a tire size of 6.00-9 was prototyped using the coil body of the conventional structure shown in FIG. 4 and the annular body of the present invention shown in FIG. 2. The tread rubber layer shown in the tread portion 3 of the tire shown in FIG. 1 and the tread rubber layer shown in FIG. Although not shown, detailed specifications and performance results are shown in Table 2 for tires with a three-layer structure, in which the rubber layer used was the intermediate rubber shown in Table 1. The performance results are shown as relative values when the value of the comparative example product is set to 100. All of the example products are excellent.

〔effect〕

Table 1 Table 2 The solid tire of the present invention uses, as its base rubber layer, a perfectly circular base rubber layer with no steps that is compressed using a molding mold, so that the rigidity is uniform over the circumference of the tire. This can greatly reduce vibrations caused by tires when the car is running.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a perspective view illustrating a ring-shaped body, Fig. 3 is a sectional view of a conventional solid tire, and Fig. 4 is a base used in a conventional solid tire. It is a front view of a rubber layer. 2-.-base rubber layer, 3-,) red rubber layer,
5.-Circle. Patent Applicant Sumitomo Rubber Industries Co., Ltd. Agent Patent Attorney Tadashi Naemura Figure 1 tx2 Figure

Claims (1)

[Claims] 1 Consisting of a base rubber layer made of rubber located at the radially innermost side of the tire and reinforced with short fiber cords, and a tread rubber layer located at the radially outer side of the base rubber layer, and the base rubber layer is a mold for molding the base rubber. A solid tire made of a ring-shaped body that has been compression-molded in advance.