JPH0930461A - Pad for crawler belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the manufacturing process, reutilize a rubber pad, and reduce the cost of a product by using a mixture of polyethylene and styrene thermoplastic elastomer as an elastic member, and providing a reinforcing core body buried in the elastic member at the time of molding. SOLUTION: A mixture mixed with polyethylene having a strong withstand load property and styrene thermoplastic elastomer having strong oil resistance and rubbery elasticity at a prescribed ratio is used as an elastic member 2. Molding materials are crushed into pellet pieces and put into the hopper of an extruder, the temperature is increased to about 250 deg.C via a heating cylinder, a plasticized fused body is fed into a die, and pressure is applied to complete a molding. A reinforcing core body 3 provided on a reinforcing plate 1 is embraced by the firm shrinking property at the time of extrusion molding and cooling, and the firm adhesiveness of the whole reinforcing plate 1 is maintained. Die molding is conducted with no complex pretreatment process applying a rubber adhesive, no skill is required for the work, no severe product management is required, and the manufacturing process can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crawler track pad attached to the tread of each track plate constituting a crawler track used for a tracked vehicle such as a bulldozer and a shovel dozer for road surface protection.

[0002]

2. Description of the Related Art Recently, as a tracked vehicle, a vehicle equipped with a rubber pad is becoming mainstream because of the need to protect the paved road surface from the tracks. Since this rubber pad is used under severe conditions, it is prone to wear, damage due to cutting and chipping, and a rubber pad having wear resistance, cutting resistance, chipping, and resistance has been proposed. (For example, see Japanese Utility Model Publication No. 63-12067).

[0003]

All of the conventional branching techniques are pursuing the rubber material itself such as abrasion resistance and cutting resistance of the rubber pad, and there are few pursuits of products involving the manufacturing process. Generally, in a shoe pad with a rubber pad, a special strong adhesive of a rubber product is applied to the bottom surface and the side surface of the reinforcing plate to prevent the rubber pad from peeling off from the reinforcing plate under any severe conditions. In order to bond the rubber pad to the bottom surface and the side surface portion of the reinforcing plate, as shown in FIG. 14, a special adhesive is sufficiently adhered to firmly fix the rubber, which requires a complicated pretreatment process. In the following, the pretreatment steps will be described step by step. First, in order to make it easier for the adhesive to come into contact with the metal fittings of the reinforcing plate that have been degreased and pressed, first the oil is removed from the entire bonding surface of the reinforcing plate. Uses high temperature steam. (30 minutes) Shot blasting ... Next, roughening is performed in order to increase the surface area of the adhesive surface as much as possible and to eliminate dust and protrusions. Adhesive (one liquid) application: Apply the first special adhesive. Sufficient adhesive strength cannot be obtained by only one time, so it is performed twice. After coating, apply hot air to dry (about 40 minutes). Visually check and if OK, move to the next step. Adhesive (two-component) application: Special adhesive with different components from one component is further applied. After application, it is naturally dried (about 30 minutes). If the interval between and is not within 3 days, the adhesive function may be lost. The sum of ~ is 3 to 4 hours. Vulcanization: A rubber material is molded into a metal fitting by a rubber press with a heat source. (Pressure: 160 tons × 40 minutes; heat pressurization at 150 ° C.) Through many steps as described above, the rubber pad for the crawler belt and the reinforcing plate are integrally joined by vulcanization to complete the crawler pad. However, in order to bond and integrate the rubber pad and the reinforcing plate, the above-mentioned complicated pre-process must be performed, and not only the process but also the auxiliary equipment for each process Space, the work man-hours for that purpose, the difference in skill of workers, the influence of temperature and humidity depending on the season, the product management of measures to prevent dust adhesion, and the burr that appears during product finishing and rubber vulcanization. There were various problems such as the disposal processing of. These factors were entangled with each other and bounced back to the product, which prevented cost reduction.

On the other hand, if a vehicle operator cannot use the rubber pad of the product on a tracked vehicle due to crack separation or the like, it is treated as waste. The treatment of this waste material has become a major social problem. Although various treatment methods have been studied in various fields, most of them are landfilled or
Currently, it is incinerated. In particular, the incineration process is a serious problem as an environmental destruction because harmful gas is generated during incineration and pollutes the air.

The present invention has tackled such problems in the past and has been researched and developed for many years. As a result, a product having a manufacturing process that solves the above problems has been succeeded. There are the following four purposes. The elastic member is made of a mixed material of polyethylene and a styrene-based thermoplastic elastomer having elasticity similar to that of rubber to improve quality. Commercialization by a simple manufacturing process. Eliminate the complicated process and control to reach the product. Reuse of rubber pad. No waste gas is generated because it is reused many times without incineration. Cost reduction.

[0006]

In order to achieve the above object, the present invention specifies, as an elastic member, polyethylene having high load resistance and styrene thermoplastic elastomer having high oil resistance and elasticity similar to rubber. In the extrusion molding machine, the reinforcing core is provided by being mixed at a ratio of, and protruding from the reinforcing plate, and embedded in the elastic member at the time of molding, and / or by providing the reinforcing plate with a through hole through which the elastic member is filled. , A molded product was formed.

[0007]

[Function] Improves the quality by mixing the polyethylene of the elastic part and the styrene thermoplastic elastomer. (Polyethylene, which has strong load-bearing capacity, and styrene-based thermoplastic elastomer, which has elasticity similar to rubber and has strong oil-like properties not found in rubber)

The manufacturing process is shortened by the shape of various special reinforcing cores inside the reinforcing plate.

Cost reduction.

[0010]

Embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment, 1 is a reinforcing plate which is pressed into a W-shaped cross section having a shape (triple grouser) along the tread surface of the shoe plate 6. 3 is a plate-shaped reinforcing core, which is provided so as to project in the reinforcing plate 1, is inserted into the elastic member 2, and is extruded.
The elastic member 2 and the reinforcing plate 1 are coupled to each other to maintain strong adhesiveness with the entire reinforcing plate 1. The reinforcing core 3 of this embodiment has a strip-like shape, the width is smaller than the head width of the bolt 4, the central portion 3c is projected upward with a space so as not to contact the link mounting bolt 8, and the lower portion becomes a space. Are doing At both ends on the two bottom portions 1 a, 1 b of the reinforcing plate 1, there are head-mounted bolts 4 for fixing the reinforcing plate 1 to the shoe plate 6. The height of this head is made higher when the height of the head of the bolt is low and the bottom portions 1a, 1 of the reinforcing plate 1 are
This is because the gap between b and the plate-shaped reinforcing core 3 becomes narrower, and the filler of the elastic member 2 at the time of molding is less likely to enter this gap, so that the gap is made as large as possible. In addition, the bottoms 1a and 1b of the reinforcing plate 1 are inserted by inserting washers.
It is conceivable to increase the gap between the plate-shaped reinforcing core 3 and. The bolt 4 is welded to the reinforcing plate 1. The end of the reinforcing core 3 is further welded to the head of the welded bolt 4. Each reinforcing core 1 is welded and fixed to the reinforcing plate 1 at four locations. The width of the reinforcing core 3 is smaller than the head width of the bolt because a welding allowance for directly welding the bolt is required. In this embodiment, the width is constant, but the width of the welded portion may be reduced and the other widths may be increased. The shape of the reinforcing core 3 is joined by partial welding in Fig. 3 (a) from the relationship between the welding allowance and the lower gap. The welding allowance to the reinforcing plate 1 in FIG. 3B is reduced. The shape shown in FIG. 2 is a rubber pad of an elastic member, and the material is a mixture of molding polyethylene (electric wire grade and film grade) having high load resistance and a styrene thermoplastic polymer having strong oil resistance and elasticity similar to rubber. Is. The mixing ratio is 60 to 70% polyethylene and 30 to 40% styrene thermoplastic elastomer. Each molding material is crushed into pellets, charged into the hopper of the extruder, heated to about 250 ° C through a heating cylinder, and the plasticized melt is fed into the mold under pressure. Complete the molded product. The reinforcement core 3 provided on the reinforcing plate 1 is held by the strong shrinkage during extrusion molding and cooling, and the strong adhesion to the entire reinforcing plate is maintained. A slight gap is formed between the reinforcing plate 1 and the rubber pad 2, but the rubber pad 2 is entwined with the reinforcing core body that is integrally coupled with the reinforcing plate 1 during molding and cooling and is firmly fixed, and the adhesiveness is maintained, so that no peeling occurs. .. Further, the reinforcing core is welded to the reinforcing plate 1 through the head of the bolt and does not peel off from the reinforcing plate.

FIG. 4 shows a second embodiment in which a reinforcing plate 10 is pressed into a U-shaped cross section having a shape (double grouser) along the tread surface of the shoe plate 6. The reinforcing core body 10b is formed by cutting and raising the bottom portion 10a of the reinforcing plate 10 and inclining the bottom portion 10a by about 30 °. Further, cut-and-raised parts 10d may be provided on both side surfaces of the reinforcing plate as in the bottom part 10a. Generally, since the rubber pad is easily peeled off from the end portion, it is very effective to provide the rubber pad on the bottom portion and the side surface at both ends. The rubber pad is also filled in the holes 10c and 10e which are cut and raised,
c, 10e are filled. The description of the elastic member 2 and the bolt 4 is the same as that of the first embodiment, and will be omitted.

5 and 6, in the third embodiment, the reinforcing core 3d extends from the bottoms 1a and 1b of the reinforcing plate 1 to the central protrusion 1c.
Are provided in plural. Others are the same as the first embodiment.

FIG. 7 shows a modification of the third embodiment in which the reinforcing cores 3d are integrated by the connecting portion 3e and straddle the central protruding portion 1c.

FIG. 8 shows another modification of the third embodiment, in which a reinforcing core is provided with a plurality of through holes 3g in one plate 3f and each foot portion 3h is provided on the bottom portion 1a, 1b of the reinforcing plate 1. It is welded and has a structure straddling the central projection 1c.

9, 10 and 11 show reinforcing plates 1 and 10.
The through holes 1e and 10e filled with the elastic member are provided in the. In this case, the through holes 1e, 1
The melt of the elastic member is filled into the back surfaces of the reinforcing plates 1 and 10 through 0e in the molding process.

FIG. 12 shows a modification of the single body shape of the reinforcing core body. (A) is an S shape, (b) is a T shape, (c) is a table shape, and (d) is a spiral shape (e). Is arrow-shaped. In the figure, p is a protrusion for welding the reinforcing core. In addition, (b) is formed by roll forming.

FIG. 13 (a). (B) illustrates one method of welding the reinforcing core 3 to the reinforcing plate 1. In advance,
Mounting positions of the reinforcing core body 3 on the bottom portions 1a and 1b of the reinforcing plate 1 and pin insertion holes 20 and 22 are provided in the reinforcing core body 3, and welding pins 24 are inserted into the holes 20 of the reinforcing plate (a). Place the reinforcing core 3 and fit the pin 24 into the hole 22 of the reinforcing core 3,
The reinforcing core 3 on the reinforcing plate 1 is, for example, arc-welded,
Weld a reinforcing core for one track pad at a time (b).

Although the molding machine has been described as an extrusion molding machine, the molding machine is not limited to this and may be an injection molding machine.
Although the footwear pad has a through hole in the footwear plate and is fixed with bolts and nuts in the example, it may be of a type in which the longitudinal end of the crawler belt is hooked and fixed.

[0019]

Since the present invention is constructed as described above, the following great effects are exhibited.

Since the rubber pad is made of a mixed material of polyethylene and styrene elastomer, it has elasticity similar to rubber, strong load resistance, and strong oil resistance, and its quality is improved as compared with conventional rubber pads.

Since the rubber pad uses a thermoplastic material of a mixed material of polyethylene and a styrene elastomer, the material can be reused. That is, scrap materials (burrs during product manufacturing,
It can be reused as many times as it can be remelted without being treated as a used product, etc., and it does not cause any pollution at all, which greatly contributes to society.

Since the rubber pad is made of a mixed material of polyethylene and styrene-based elastomer, it is different from the conventional vulcanized rubber molding method to the plastic molding method, and there is no complicated pretreatment step of applying the adhesive for rubber, and it is molded as it is So
No skill level is required, product management is not critical, and the manufacturing process can be shortened.

Since the rubber pad is firmly entwined and fixed not to the reinforcing plate but to the reinforcing core body to be inserted into the molding material at the time of molding, a small amount of non-adhesion of oil or dust on the reinforcing plate does not cause much problem. Moreover, the resistance of the rubber pad to peel from the reinforcing plate is better than that of the conventional rubber pad.

Since there is no pre-treatment step of the conventional complicated strong adhesive application for rubber and the molding is performed as it is, the skill level of the work is not required, the product management is not critical, and the manufacturing process can be shortened. .

In connection with the above, it is possible to significantly reduce the price of the rubber pad product.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an overall perspective view showing a reinforcing plate and a reinforcing core body according to the first embodiment of the present invention and a partial perspective view showing another shape of the reinforcing core body.

FIG. 4 is an overall perspective view showing a reinforcing plate and a reinforcing core body according to a second embodiment of the present invention.

FIG. 5 is a partial perspective view showing a reinforcing core body according to a third embodiment of the present invention.

FIG. 6 is a partial sectional view of FIG. 5;

FIG. 7 is a partial perspective view showing a modified example of the reinforcing core body.

FIG. 8 is a partial perspective view showing another modification of the reinforcing core.

FIG. 9 is a partial perspective view showing an example in which a through hole is provided in the reinforcing plate of the present invention.

FIG. 10 is a general cross-sectional view showing the entire track pad of FIG.

FIG. 11 is a partial perspective view showing another example in which a reinforcing plate is provided with a through hole.

FIG. 12 is a perspective view showing a modified example of the reinforcing core of the present invention.

FIG. 13 is a partial perspective view showing a method of welding a reinforcing core to a reinforcing plate.

FIG. 14 is a process diagram showing a pretreatment process for conventional rubber vulcanization.

[Explanation of symbols]

 1, 10 Reinforcement plate 2 Elastic member (rubber pad) 3 Reinforcement core 4 Bolt

Claims (1)

[Claims] 1. A crawler belt pad in which an elastic member constituting a tread is fixed to a reinforcing plate formed in a shape along the tread of the crawler, and the elastic member is polyethylene or styrene-based in a removable pad fixed to the crawler. As a mixed material with a thermoplastic elastomer, protruding from a reinforcing plate, at the time of molding, a reinforcing core and / or a reinforcing plate embedded in the elastic member is provided with a through hole through which the elastic member is filled. A crawler track pad characterized by being formed into a product.