JPS5855070B2 - Manufacturing method for tire bead protection material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is mainly used as a protective material to prevent damage to the bead portion that frequently occurs during loading and unloading in the transportation of large pneumatic tires such as tires for construction vehicles.
In particular, the present invention relates to a method for manufacturing an easy-to-manufacture tire bead protection material that is stable and prevents the fixed portion from loosening due to external force.

To begin with, tires for construction vehicles used for construction work or mining underground resources are large, with the largest ones measuring up to 3.5 meters in diameter and weighing up to 3,500 kg.
Due to their large size and unique shape, handling during the transportation process is extremely difficult.

Therefore, loading and unloading is carried out by passing lobes through the bead of the tire and hoisting it up, or by hanging it on the fork of a forklift.As a result, the bead of the tire is often damaged during the work, especially when the tube is lifted. In the case of flat tires, Cma will cause fatal damage and become unusable.

Therefore, various methods have been used to protect the tire bead, and the simplest method is to attach a circular wooden board with a cutout through which the rope is passed, to both sides of the tire bead, and then use a steel band to protect the tire bead. There is something that tightens and fixes both wooden boards.

However, this has the disadvantage that the wooden board is easily damaged, making it dangerous as a protective material.

In addition, as disclosed in Japanese Utility Model Application Publication No. 5149501, there is also a method of integrally molding the brim seal annular body, but this manufacturing requires a large and heavy mold, and furthermore, the tire size is large. Since molds must be manufactured for each case, a large investment in equipment is required, and the cost of the protective material is also high.

Furthermore, there is a method disclosed in Japanese Patent Publication No. 53-17205, in which arc-shaped molded bodies having an angular cross-section are connected by belt lacing, embedding of fasteners, etc. to form an annular body.

In this method, in the case of a belt lacing connection, it is necessary to cover the connection part with another rubber-like substance, and care must be taken to fix it so that it does not fall off.

In addition, in the case of fasteners, not only does the cost of the metal fittings and production increase due to the need to embed the fasteners during molding, but such belt lacing joints tend to bend easily and damage the bead of the protective material. The fixation is weak, and
In the case of embedding a fastener, the joint's adhesion to the bead is poor, and its fixation to the bead is also weakened, both of which are likely to cause movement friction. Therefore, tightening with a band to the tire is not recommended. This includes problems such as the need to increase the number of locations.

Therefore, the inventors particularly investigated a method of strongly connecting long linear rectangular rubber plates to obtain strong fixation and creepability to the bead portion, and found a method that could be easily manufactured. We have devised a method that is both highly safe and able to solve the above problems.

That is, a mold with an L-shaped cross section in the molding cavity is used, and a flanged rectangular rubber plate with an L-shaped cross section reinforced by embedding reinforcing material such as cords or piano wire is integrally molded. , relates to a method of forming a flange-shaped annular body by overlapping and splicing both ends thereof to form an abutment portion having approximately the same length as the inner circumference of the bead portion of a construction vehicle tire.

The flanged rectangular plate-like body produced by this method is produced by forming a linear molded body into a long length using so-called feed molding, in which green material is supplied from one end of the mold and the molded body is continuously taken out from the other end. The tire may be cut to a length required for each tire used, or may be molded with a mold having the required length.

To fix this flanged rectangular rubber plate cut to a predetermined length to the flanged annular body by overlapping joints, use special bolts and fixing bolt holes that pass through both ends of the overlap joint, or the upper part of the bolt hole. A method is used to forcibly bury the bolt head into the rubber layer by strongly tightening the bolt head by forming a shallow bolt head position groove in the rubber layer.

This bolt head forms a circular or polygonal plate-shaped head having a considerably larger area than bolt heads commonly used in the past.

By forming the plate-shaped head with a large area, the frictional resistance with the rubber layer of the head is increased, and when tightening the nut, it is possible to tighten it strongly without idling, and the head surface of the plate-shaped head is The lap joint is fixed by strongly forcibly burying the rubber layer below the surface of the rubber layer on the upper layer of the lap joint, which is in contact with the bead base.

Because the plate-shaped head is forcibly buried in the rubber layer, the rubber layer around the plate-shaped head is strongly compressed, and the plastic deformation that appears as creep in the rubber layer, which is a viscoelastic body, is eliminated.
The rubber surrounding the plate-shaped head of the bolt becomes a comb with strong supporting properties that supports a constant large external force, and has the function of completely preventing the plate-shaped head from coming into contact with the tire bead base. Since deformation is sufficiently eliminated, and a large reaction force is applied to the nut, there is no risk of the nut loosening during use, contacting the bead base, or coming off, ensuring stable fixation. It becomes something that can be sustained.

That is, the simple tightening of bolts and nuts is only a means, and an effective effect can be obtained.

If you use commonly used bolts and nuts to fix rubber plates together, they will spin idly, or even if you use an auxiliary tool to prevent them from idling, the holes for the bolts drilled in the rubber may curl back. It tends to be pushed out and spread out, and if it is tightened too strongly, it will pierce through or break through, making it impossible to secure it stably.

If the nut were to come loose, the bolt head would come into contact with the bead base of the tire and cause damage, resulting in major damage, so the structure of the bolt is an important factor.

Therefore, the special bolt has a circular or polygonal plate head, and its diameter or diagonal diameter is in the range of 2.5 to 5 times the diameter of the threaded part, that is, the bolt diameter. ,
The thickness is 0.3 to 0.0 mm of the diameter of the threaded portion, that is, the diameter of the bolt.
6 times the range.

Selection from within the above range is determined appropriately depending on the rubber quality and hardness.

Note that if the diameter or diagonal diameter of the above-mentioned plate-shaped head is smaller than 2.5 times the bolt diameter, when tightening the nut, the bolt head will push the bolt hole wider, making it impossible to pierce through to the opposite side. do not have.

On the other hand, if the bolt is thicker than 5 times, more force than necessary is required to force the bolt head into the rubber layer, and it is difficult to bury the head lower than the surface of the rubber layer.

The hardness of the rubber layer used is relatively high, and is at least 65 degrees or more, often in the range of 75 to 95 degrees, as measured by a JIS spring type rubber hardness meter.

Next, specific fixing means will be mentioned.

The molded rectangular rectangular rubber plate with a predetermined length described above is stacked on top of each other at both ends. At least two bolt holes are drilled at each end, and around the bolt holes in the comb layer on the surface of the upper layer of the lap joint, an O
A circular or polygonal plate head position groove with a depth of ~0.5 times is provided, the other end is overlapped as a lower layer, and a circular or polygonal plate head with a diameter or diagonal diameter of 25 to 5 times the bolt diameter is provided. A special bolt with a square plate-shaped head and a thickness of 0.3 to 0.6 times the bolt diameter is inserted through the bolt hole in the upper layer of the lap joint, and the head surface of the plate-shaped head is , tightened with a nut through a washer of the same diameter as the plate-shaped head of the bolt on the back side of the lower layer of the lap joint until the height is below the surface of the comb layer, forming a ring-shaped body with a flange. It is.

Next, aspects of the present invention will be specifically described in detail based on drawings showing an example of implementation.

FIG. 1 is a perspective view showing the state of the bolt holes at both ends of the flanged rectangular rubber plate, FIG. 2 is a cross-sectional view of the lap joint of the tire bead protection material, and FIG. 3 is a tire according to the present invention. FIG. 2 is a partially cross-sectional perspective view showing an example of a state in which a bead protection material is attached to a construction vehicle tire.

In the figure, reference numeral 1 denotes a rectangular rubber plate with a flange, which has an L-shaped cross section and is composed of a band portion 1a and a flange portion 1b.

A is one end of the lap joint, B is the other end of the lap joint, and 2 is a bolt hole, which is provided through the lap joint, and the hole diameter is the diameter of the screw 5b of the special bolt 5, or Form to approximately the same diameter as the bolt diameter.

Reference numeral 3 denotes a position groove for the plate-shaped head of the special bolt 5, which is formed in the same shape as the plate-shaped head and concentrically with the bolt hole.

This 0-position groove plays an internal role in order to forcibly install the plate-shaped head, and since its depth d needs to be shallow, it It is formed to be 0.5 times or less the thickness.

If there is no positioning groove, the plate-shaped head can be forcefully inserted and removed as it is.

That is, the depth d of the position groove is the thickness θ) of the plate-shaped head) 0 to 0
．． It is said to be 5 times more.

4 is a reinforcing material, which is appropriately buried and reinforced with cords such as tire cords or reinforcing materials such as piano wire, and the material of the reinforcing material, the number of plies, and the buried position thereof correspond to the type of structure of the tire bead protection material. To be determined accordingly.

In order to form a flanged annular body by overlapping the rectangular bodies of the flanged rectangular rubber plates 1 described above, as shown in FIG.
The end part B is the lower layer, the surface part UP is overlapped, the bolt holes 2 of both are aligned, and the plate-shaped head 5a of this special port t-5 is fixed with a special bolt. As shown, the diameter of the threaded portion 5b, that is, the bolt diameter is in the range of 2.5 to 5 times, and the thickness t is formed in the range of 0.3 to 0.6 times the diameter of the threaded portion 5b, that is, the bolt diameter. Insert this special bolt 5 from the front surface UP side of the strip 1a at the end A, and then insert the special bolt 5 from the back surface B of the strip 1a at the end B.
A nut 7 is attached to F through a washer 6 of the same size as the plate-shaped head 5a.
, the head surface 5c of the plate-shaped head 5a is the surface portion U of the band-shaped portion 1a.
It is firmly tightened and fixed until it is buried below the surface of the rubber layer of F.

The above configuration is an example in which the position groove 3 of the plate-shaped head is formed in the surface part UF of the end part A, but conversely, the position groove 3 is formed in the end B side where the flange part 1b is cut out. It is also possible to set this layer to be an upper layer and to overlap it, and to overlap it with the flange portion 1b as a lower layer.

FIG. 3 shows an example of this O-overlap joint.

In addition, in this lap joint, one end or both ends are cut out as shown in the diagonal cutout 8 in Fig. 1.
It is desirable to reduce the level difference in the overlapped portion.

In addition, for products with dimensions that are manufactured in large quantities, special molds are used.
It is desirable to mold it to the required length.

In this case, step portions may be formed at both ends, and the step portions may be joined together to reduce the step difference.

In this case, it is desirable from an economic point of view to add and bury a reinforcing layer in both end regions for the purpose of reinforcing the bolt holes to reduce the overall thickness.

In addition, in the tire bead protection member P used for relatively small tires, it is desirable to cut out the flange portion 1b of the lap joint at one end with a knife, and in the tire heat protection member P used for relatively large tires, Also overlap the flange part 1b,
As in the case of the band-shaped part 1a, it is desirable to connect by tightening the special bolts 5 (with a trowel).

As described above, the constructed tire bead protection material is fixed to the bead portion of a construction vehicle tire, as shown in an example in FIG. 3, to prevent damage to the bead portion.

The figure is an omitted diagram and shows the bead portion fixed to one side, or the other side is fixed in the same way.

In the figure, ORT is a tire for a construction vehicle, TB is a bead portion of the tire, BB is a bead base portion, and P is a tire bead protection member.

As shown in the figure, the outer surface portion UF of the tire bead protection member P is placed along the bead base portions B'B on both sides of the construction vehicle tire ORT, and the flange portion 1b is placed along the outer side of the bead portion TB of the 51st tire. The bead portion is protected by making contact with it and fixing it at several points with steel bands SB.

As explained above, the tire bead protection material of the present invention is
Tire bead protection materials of various sizes can be easily made by simply cutting long pieces of rectangular rubber plates with flanges and having a rectangular cross-section shaped into the required length and splicing them together using special bolts. It is not only a scale that can be manufactured, but also has a very simple manufacturing process, does not require large capital investment, and can be manufactured at low cost.Special bolts with large plate-shaped heads are used to secure lap joints. Therefore, we used a method of forcefully embedding and fixing the plate-shaped head of the bolt into the rubber layer on the surface of the tire bead protection material until the head surface of the bolt was below the comb layer surface υ. The rubber layer around the head is
Plastic deformation is eliminated, a strong supporting rubber is formed that supports a large unchanging external force, and the plate-shaped head exhibits the function of completely preventing contact with the bead base of the tire. Since a large unchanging reaction force acts on the nut, there is no risk of the nut loosening and coming into contact with the bead base or coming off during use.・A single tightening of the nut is only a means and has the characteristic that an effective effect can be obtained.

In addition, since the linear molded body is transformed into an annular body by overlapping joints, a large contact stress is applied when it is fitted and fixed to the tire, and it has the characteristic of exhibiting good fixing performance and protection. It is something that you have.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the state of the bolt holes at both ends of the flanged rectangular rubber plate of the tire bead protection material of the present invention;
Fig. 2 is a cross-sectional view of the lap joint of the tire bead protection material, and Fig. 3 is a perspective view, partially in section, of an example of the state in which the tire bead protection material is attached to a construction vehicle tire. Top: rectangular rubber plate with flange, 1a...
...Striped part, 1b...Flange part, A, B...
...End, 2...Bolt hole, 3...
Position groove of plate-shaped head, 4... Reinforcement material, 5...
...Special bolt, 5a...Plate head, 5b...
...Screw part, 5c...Head, 6...
・Washer, 7... Nut, UF... Front part, BP... Back part.

Claims (1)

[Claims] 1 At both ends of the required length of a rectangular rubber plate with a rectangular rubber plate shaped into a straight line or with an approximately L-shaped flange, made of relatively hard rubber reinforced by embedding reinforcing materials such as cords or piano wire. , bolt holes with approximately the same diameter as the bolt passing through the overlap joint are provided in at least two places, and special bolts are used to overlap both ends and when fixing, the upper layer surface of the overlap joint is Around the bolt holes in the rubber layer,
Concentrically with the bolt hole, the thickness of the plate head of the bolt is O~0.
A circular or polygonal plate-shaped head position groove with a depth of 5 times is provided, and the circular or polygonal plate-shaped head has a diameter or diagonal diameter of 25 to 5 times the bolt diameter, Insert a special bolt with a thickness of 0.3 to 0.6 times the bolt diameter through the bolt hole on the surface side of the upper layer of the lap joint θ, and insert it into the back side of the lower layer of the lap joint. A washer of the same size as the plate-shaped head is used to firmly tighten and fix the plate-shaped head with a nut until the head surface of the plate-shaped head is buried below the surface of the rubber layer on the surface, forming a flanged annular body. A manufacturing method for a tire bead protection material characterized by: