RU2577271C1 - Device for production of polyurethane tire with filler of foamed polyurethane - Google Patents

Abstract

FIELD: motor car construction.

SUBSTANCE: claimed device comprises the first split mould provided with filling bores to feed polyurethane and air release drain bore and composed of two split covers to be tightly jointed at filling in the mixes. Inner shape of said split as-closed covers complies with the tire outer shape. Second smaller-size split die consists of two split covers. The rim inner surface is shaped to the wheel hub seat while the outer surface can adhere to polyurethane and is provided with thrust for transfer of tangential forces. The rim outer surface diameter and shape at the points of conjugation with the first and second die inner surfaces comply with the first and second die surface ID and shape while its width is sufficient for closure of the first die inner cavity closure. The smaller die inner surface shape complies with that of the tire protective ply inner surface.

EFFECT: production of the tire with the filler of foamed polyurethane.

5 cl, 2 dwg

Description

The invention relates to the field of devices (equipment) for the manufacture of tires from polyurethane, and more particularly to the field of devices (molds) for the manufacture of polyurethane tires with a filler of foamed polyurethane.

Currently, the widest application for various types of wheeled vehicles is pneumatic rubber tires, which are an elastic shell designed to be mounted on the wheel rim, and having an annular cavity filled with air or gas under pressure [1]. The main component of the pneumatic tire is the tire - an annular hollow shell that directly perceives the forces arising during operation. The basis of the tire is the carcass, representing the power part of the pneumatic tire and consisting of one or more layers of cord, fixed on the side rings, forming the rigid part of the tire of the pneumatic tire and ensuring its fastening on the wheel rim. To strengthen the strength of the tire, a breaker is used, consisting of layers of cord located between the tread and the carcass. Pneumatic tires are chamber and tubeless.

Pneumatic tires have good shock-absorbing properties, but they are sensitive to cuts and punctures, which cannot be prevented in workshop and factory conditions. As a result, massive tires have been developed for vehicles used in workshop and factory conditions [2, 3], which are a continuous ring-shaped structure in which there is no shock-absorbing cavity.

Massive tires are resistant to cuts and punctures and do not require maintenance during their operation, however they are much worse than pneumatic ones, they soften shock when driving on bumps, which leads to excessive loads on the vehicle frame and premature failure of the vehicle. The cushioning properties of solid tires can be enhanced by various design tricks. In particular, a multilayer massive tire is known [4], in which there are tread, damping and landing parts made of spirally wound and vulcanized to each other layers of rubber of various thicknesses with different elastic moduli. Such a tire has higher shock-absorbing properties compared to a homogeneous massive rubber tire, however, for use in difficult driving conditions, its shock-absorbing properties are insufficient, and the manufacturing process requires a wide range of sheet rubber grades of various thicknesses with specified elastic moduli.

A compromise tire option for workshop operating conditions are tires of the “gusmatic” type [5] (“superelastic”). They are a combination of tires - an annular shell located inside the annular shock-absorbing cavity and an annular shock-absorbing element located in the shock-absorbing cavity of the tire made of sponge rubber. In this case, the outer dimensions of the shock-absorbing element and the inner dimensions of the shock-absorbing cavity coincide. The advantages of such tires is that their service life is about 1.5-2 times higher compared to pneumatic ones, they are resistant to cuts and punctures and practically do not require maintenance during operation. However, in their damping properties, Gusmatic tires are inferior to pneumatic ones and their damping properties make up less than 80% of such properties of a pneumatic tire [6].

BSK company offers tires in which 100% of the internal cavity of the rubber pneumatic tire is replaced by a polyurethane compound [7]. The result is a tire resistant to punctures and cuts, but not without a number of disadvantages:

- insufficient damping ability;

- abrasive wear of the walls of the cavity due to friction at the border with the polyurethane filler;

- tire heating at increased speed due to friction noted above;

- excessive tire weight compared to pneumatic.

However, tires of the Gusmatic type are not without a number of disadvantages. Firstly, they are inferior in terms of shock-absorbing properties to pneumatic tires, which causes additional mechanical effects on the bearing structural elements of vehicles. Secondly, such tires cannot provide movement at high speeds due to their heating and overheating, leading to tire failure. Overheating is associated, in particular, with the fact that the surface of the shock-absorbing element is not connected with the inner surface of the shock-absorbing cavity of the tire, which leads to mutual displacement and friction of these surfaces and, as a result, to concomitant heating and abrasive wear. In addition, the sponge rubber filler loses its elasticity over time due to aging of the rubber and the destruction of pores, the shock-absorbing properties of the tire deteriorate, and the rolling resistance increases.

The increasing environmental requirements for indoor outdoor vehicles are driving new tire requirements. Rubber tires made from a mixture of rubber and carbon black (soot) wear out intensively at high loads, and abrasion products, together with dust, rise into the air and enter the human body. For this reason, rubber tires containing carbon black must not be used indoors. In addition, many substances in rubber tire formulations are carcinogenic. These include, in particular, vulcanization activators and accelerators, aromatic softeners, rubber monomers, benzopyrenes and N-nitrosamines, which, during processing and vulcanization of rubber, form toxic and hazardous chemical compounds with carbon black. When tires are used, these substances are released into the atmosphere.

Currently, in world practice, for working indoors in tire formulations, carbon black is replaced with non-toxic silicon oxide, but this solution leads to a reduction in tire life by 10 ... 15% due to a decrease in abrasion resistance while increasing production costs. Massive polyurethane tires, which are a layer of polyurethane applied to a metal bandage, optimally meet environmental safety requirements. Such tires have 3 ... 5 times higher abrasion resistance compared to rubber tires filled with silicon oxide. However, such tires have low cushioning ability.

Currently, neither pneumatic rubber nor massive rubber or polyurethane tires for warehouse and handling equipment meet the set of sanitary and hygienic and operational requirements.

To a large extent, the disadvantages of both known pneumatic and solid tires could be eliminated by a polyurethane tire with a filler made of foamed polyurethane containing an annular rotation sheath with a tread part and sidewalls forming a shock-absorbing cavity with an annular filler made of foamed polyurethane located in it, whose outer dimensions correspond to the size of the shock-absorbing cavity. The surface of the cushioning cavity is connected to the surface of the annular filler, the supporting surfaces of the sidewalls are interconnected by a reinforced polyurethane or metal ring connected to them, while the outer surface of the ring adjacent to the filler, located between the sidewalls, is connected to the filler. The inner cylindrical or conical surface of the ring serves for its landing on the axis. Such a tire with a filler (chamber) made of foamed polyurethane with microcapsules included in its structure filled with gas under pressure, is a single two-component array, continuous on the outside and porous inside. The solidity of the array is ensured by the presence between the filler surface and the inner surfaces of the tread portion, the sidewalls and the outer surface of the reinforced polyurethane ring of a continuous bond formed during the polymerization of polyurethane. In this case, the load-bearing capacity of the tire is determined not by the gas pressure in the tire and its power frame, but by a polyurethane foam filler, which consists of microcapsules filled with gas under pressure. After polymerization, the filler is an elastic cellular structure, in its bearing capacity significantly superior to the multilayer frame. In this case, the use of a breaker can be eliminated in the tread part of the tire, since the cellular structure of the filler increases the survivability of the tire during punctures and cuts to the characteristics of a massive tire.

The manufacture of the described polyurethane tire with increased cushioning ability, approaching the cushioning capacity of pneumatic tires, requires specialized equipment.

As you know, products from flexible polyurethanes are obtained by casting into collapsible matrices [8-10]. In this case, as a rule, the metal rim of the wheel is part of the casting matrix, and therefore the finished product is a non-separable construction of the metal wheel with a tire made of elastic polyurethane.

A known mold for the manufacture of tires from flexible polyurethane with elastic deformable knitting needles [11]. The specified mold is detachable and in its design contains end caps, an outer ring for forming a tread and internal forming elements, as well as a metal wheel rim. The disadvantage of the described mold, selected for the prototype, is that it does not allow the production of tires with a shock absorbing volume from a foamed polyurethane with microcapsules included in its structure filled with gas, which is a single two-component array, continuous on the outside and porous inside.

The aim of the described technical solution is to overcome the drawback of the prototype noted above, namely, to ensure the possibility of manufacturing a tire with a filler (chamber) of foamed polyurethane.

This objective of the invention is achieved by the fact that the proposed device for the manufacture of a polyurethane tire with a filler of foamed polyurethane, along with the first large detachable mold, designed to form the outer protective layer of the tire and tread, equipped with filling holes for supplying polyurethane and drainage holes for air outlet consisting of two detachable covers, hermetically connected to each other when pouring the mixture, and the internal form of these detachable covers in a closed container melting corresponds to the external shape of the tire, additionally contains a second detachable mold of smaller sizes, designed to form an internal shock-absorbing layer, consisting of two detachable covers equipped with filling holes for supplying polyurethane foam and drainage holes for air outlet, while the shape of the inner surface of the small press the shape corresponds to the shape of the inner surface of the outer protective layer of the tire, manufactured by pouring the first mold after placing castings from m a scarlet mold and a rim, the inner surface of which is made in the form of a seat for the wheel hub, and the outer surface is made of adhesion to polyurethane and equipped with stops for transmitting tangential forces, while the diameter of the outer surface of the rim corresponds to the inner diameter of the first and second molds, and its width is sufficient to close the inner cavity of the first mold.

The technical essence of the invention is illustrated by the drawings shown in figures 1-2. Moreover, the device for manufacturing a polyurethane pneumatic tire includes a large and small mold.

The figure 1 shows the design of a small mold designed for the manufacture of a shock-absorbing volume, and the figure 2 shows the design of a large mold intended for the manufacture of a protective layer of a tire, which is a single array with a previously made small mold (figure 1) shock absorbing volume.

A device for the manufacture of a polyurethane tire with a filler of foamed polyurethane contains:

- a small detachable mold 1, equipped with filling holes 2 for supplying polyurethane and drainage holes 3 for air outlet, consisting of two split covers 4 and 5, which are connected by bolts 6 before filling;

- a large detachable mold 7, equipped with filling holes 8 for supplying polyurethane and drainage holes 9 for air outlet, consisting of two detachable covers 10 and 11, which are joined by bolts before pouring 12. Moreover, on the surface of the mold forming contact with expensive surface, a relief pattern can be applied to ensure the formation of a tread;

- rim 13, which can be made of metal or polyurethane high hardness.

The inner surface 14 of the rim 13 is made in the form of a seat for the wheel hub 15. The outer surface of the rim is made adhesive to polyurethane and provided with stops 16 for transmitting tangential forces. The diameter and shape of the outer surface of the rim 13 in places of its mating with the inner surfaces of the first (small) 1 and second (large) 7 molds correspond to the inner diameter and shape of these surfaces of the first 1 and second 7 molds. The width of the rim 13 is sufficient to close the inner cavity of the large mold 7. The shape of the inner surface of the small mold 1 corresponds to the shape of the inner surface of the outer protective layer of the tire, made by pouring the large mold 7 after placing the casting 17 from the small mold Form 1.

The manufacturing process of a polyurethane tire filled with foam polyurethane is as follows.

First, a shock absorbing insert is made from porous (foamed) polyurethane. For this, a rim 13 is installed in the small mold 1, the halves of the mold 4 and 5 are pulled together with bolts 6, and foamed polyurethane is fed through the filling hole 2. After the polymerization process is completed, halves 4 and 5 of the mold 1 are disconnected and the casting 17 rigidly connected to the rim 13 is removed. Then the casting 17 together with the rim 13 is placed in a large mold 7, the halves of the mold 10 and 11 are pulled together with bolts 12 and through the filling hole 8 serves polyurethane. In this case, the composition of polyurethane should provide high strength tires - its sidewalls and tread. During polymerization of polyurethane in the mold 7, a casting 17 made of foamed polyurethane is bonded to the inner surfaces of the sidewalls 18 and the tread 19 of the tire, while the supporting surfaces of the sidewalls are rigidly bonded to the edges of the rim protruding beyond the amortization volume. After the polyurethane has cured, the finished tire is removed from molds 7.

It should be noted that the inner surfaces of the small split mold 1 (namely, the inner surfaces of the split covers 4 and 5) and the large split mold 7 (namely, the inner surfaces of the split covers 10 and 11) to eliminate the adhesion of the foamed polyurethane (when the manufacture of a foamed cushioning insert in the mold 1) and polymerized polyurethane (when forming the outer protective layer of the tire and tread in the mold 7) can be coated with a technological release agent. As a release agent, it is advisable to use one of the Penta-120 series lubricants, in particular the P-126P grade lubricant manufactured by Penta-91 LLC (Moscow).

When the rim 13 is made of metal, its outer surface is roughened and can be coated with an adhesive composition to improve the adhesion of the supporting surfaces of the polyurethane sidewalls of the tire and its foamed filler to the rim 13. The following adhesives are advisable as an adhesive composition - AK-070 primer, primers of the brands “ Tixon ", E802, M100. However, the best adhesion of the rim 13 of the supporting surfaces of the polyurethane sidewalls of the tire and its foam filler is ensured in the manufacture of the rim 13 of high hardness polyurethane.

In accordance with the process described above, an experimental batch of tires was manufactured at the applicant enterprise, tests of which confirmed their high performance in real workshop conditions.

Information sources

1. GOST 22374-77. Tires are pneumatic. Design. Terms and Definitions.

2. GOST 28630-90. The tires are massive. Terms and Definitions.

3. GOST 5883-89. Massive rubber tires. Technical conditions

4. Cashless Yu.T. and others. Multilayer massive tire. RF patent No. 2268155, cl. IPC V60S 7/10.

5. Savosin B.C., Bograchev M.L. Massive tires. M .: Chemistry, 1981.

6. The company "Bulkar". Promotional materials. 2014.

7. Filling polyurethanes for tires instead of air. The company "BSK". Promotional materials. 2014.

8. Mazur V.V., Enaev A.A. Mold for the manufacture of wheels made of polymer composite materials. RF patent No. 79490, cl. IPC V29C 43/36.

9. Mazur V.V. A method of reinforcing wheels with elastic deformable spokes and a mold for making wheels. RF patent No. 2357861, cl. IPC V29C 43/36.

10. Mazur V.V. Matrix for casting a polyurethane tire. RF patent No. 2452625, cl. IPC V29C 33/44.

11. Mazur V.V. Mold for the manufacture of tires from flexible polyurethane with elastic deformable knitting needles. RF patent No. 2413611 class. IPC V29C 33/44.

Claims (5)

1. A device for the manufacture of a polyurethane tire with a filler of foamed polyurethane, containing a first detachable mold equipped with filling holes for supplying polyurethane and drainage holes for air outlet, consisting of two detachable covers that are hermetically connected to each other when pouring the mixture, and the inner form of said split covers in a closed state corresponds to the external shape of the tire, characterized in that there is a second split mold of smaller sizes, consisting of two split x covers, and the rim, the inner surface of which is made in the form of a seat for the wheel hub, and the outer surface is made of adhesion to polyurethane and is equipped with stops for transmitting tangential forces, while the diameter and shape of the outer surface of the rim in places of its mating with the inner surfaces of the first and the second molds correspond to the inner diameter and shape of the indicated surfaces of the first and second molds, and its width is sufficient to close the inner cavity of the first mold, while the shape of the inner surface of the small mold corresponds to the shape of the inner surface of the outer protective layer of the tire, which is produced by pouring the first mold after placing the casting from the small mold in it. 2. The device according to claim 1, characterized in that the inner surfaces of both molds are coated with a technological release agent. 3. The device according to claim 1, characterized in that the rim is made of metal, and its outer surface is made rough. 4. The device according to paragraphs. 1 and 3, characterized in that the outer surface of the rim is coated with a technological adhesive composition. 5. The device according to claim 1, characterized in that the rim is made of high hardness polyurethane.

Images